hydraulic jack safety valve factory

The present invention relates to an improved safety valve structure for a hydraulic jack, particularly to an improved structure of the safety valve inside a pump base of the jack so that high pressure hydraulic fluid can smoothly and accurately flow through the valve and return to a reservoir.

A one-way valve is usually provided between the reservoir and the pump base of a hydraulic jack. The one-way valve is used to control hydraulic fluid flowing from the reservoir into a pump. The valve also cooperates with the up-and-down movement of a lever on the jack so that the hydraulic fluid can be forced into a pressure tank for pushing a piston upward. When the jack is overloaded and the hydraulic pressure inside the jack has reached a predetermined limit, a safety device is needed to discharge the hydraulic fluid back into the reservoir. A conventional safety device uses a steel ball and a safety spring secured by an adjustment screw. The adjustment screw is used to adjust the pressure of the safety spring which presses against the steel ball. When the pressure inside the pressure tank is higher than the pressure of the safety spring set by the adjustment screw, the steel ball will automatically be pushed rearwardly against the force of the safety spring so that the safety spring is compressed, thus enabling the steel ball to disengage from a valve seat. Thus, the path previously closed by the steel ball is opened and the hydraulic fluid can return to the reservoir, thereby lowering the pressure within the pressure tank and preventing the pressure tank from cracking or exploding. However, the operation of the above arrangement is not reliable, since it is easy for the steel ball to deviate from an opening path of movement. Therefore, discharge of the hydraulic fluid is unstable and results in rough operation.

The main object according to the present invention is to provide an improved safety valve structure for hydraulic jacks. The structure is provided with a push pin, a safety spring and an adjustment screw. The end of the push pin is placed inside the axial hole of the adjustment screw. The adjustment screw is used to adjust the compression of the safety spring so as to control the pushing force of the push pin. By such configuration, the push pin can be used to seal the opening as well as to guide the hydraulic flow when the push pin is retracted. Thus, it provides for smooth operation when the hydraulic oil is discharging.

As shown in FIGS. 2 and 3, a safety valve according to the present invention is provided inside a valve body of a one-way valve 1 of a hydraulic jack. The one-way valve 1 is provided inside a pump base 6 of the hydraulic jack and a pump 7 is provided on the pump base 6. The one-way valve 1 includes a cylindrical valve body. The cylindrical valve body has an annular recess or slot 11 formed in an exterior wall thereof.

An L-shaped oil inlet channel 12 defines an oil inlet port 121 at slot 11 and a port opening at the top surface of the one-way valve 1. A filtering screen is provided in the inlet channel 12 at oil inlet port 121. The L-shaped oil inlet channel 12 is a two-step channel having a larger diameter portion at the top and a smaller diameter portion at the bottom. A steel ball 123 and a compressed spring 124 are provided in the larger portion of the channel. The compressed spring 124 engages a projection defining the upper opening so as to be secured without disengaging. Also, the steel ball 123 seals the upper neck opening of the smaller diameter portion of the channel. In addition, the top surface of the one-way valve 1 is provided with an oil discharge port or hole 13, which is a two-step passage or hole having a larger diameter bottom portion and a smaller diameter top portion. The larger diameter portion of the channel is provided with a steel ball 131 and a compressed spring 132. The compressed spring 132 is secured in place by engaging an inwardly extending projection defining a bottom opening. Also, steel ball 131 seals the bottom opening of the smaller diameter portion. In addition, the wall of the annular slot 11 of the one-way valve 1 is provided with a safety oil discharge port or hole 14, which communicates with the smaller channel portion of the oil discharge port or hole 13.

As shown in FIGS. 2 and 3, the safety oil discharge hole 14 is a two-step passage or hole having a smaller diameter portion 141 which communicates with the smaller portion of the oil discharge hole 13. A rearward section of a larger diameter portion 142 is provided with inner screw threads. A push pin 2, as well as a safety spring 3, are placed in the larger portion 142 and an adjustment screw 4 is used to secure the pin 2 and spring 3 in place. A forward portion of push pin 2 is a cone-shaped body 21 and a rearward portion is a two-step rod or post 22, in which a large-diameter portion is inserted into the safety spring 3 in the axial direction, the small-diameter portion is inserted into an axial hole 41 of the adjustment screw 4. In this configuration, the resilient force of the safety spring 3 is applied so that the cone-shaped body 21 of the push pin 2 seals an end of the smaller portion 141 of the safety oil discharge passage 14. An end of safety spring 3 is engaged by adjustment screw 4, which is screwed and secured inside the larger portion 142 of the safety oil discharge hole 14. Also, the force of the safety spring 3 and thus the sealing force of push pin 2, can be adjusted by adjusting the adjustment screw 4 in the larger portion 142 of the safety oil discharge hole 14. In addition, the axial hole 41, provided on top of the adjustment screw 4, is used for discharge of the hydraulic fluid.

By use of the push pin 2, provided in the safety oil discharge hole 14 to cooperate with the safety spring 3 and the adjustment screw 4, the pump 7 can be removed and the one-way valve 1 can be taken out. By turning the adjustment screw 4, the compression ratio of the safety spring 3 can be set and the force of the push pin 2 acting against the smaller portion 141 of the safety oil discharge hole 14 can also be adjusted. Thus, the force from the safety spring 3 pushing against the push pin 2 can be set as the critical value of the hydraulic safety load coefficient. In other words, safety spring 3 and push pin 2 limit the pressure of the hydraulic jack. During operation, when the safety load value of the hydraulic fluid within the jack reaches the limit (i.e., when the load exceeds the setting of the push pin 2), the push pin 2 inside the safety oil discharge hole 14 is displaced backwardly by the hydraulic pressure and compresses the safety spring 3. At this time, the push pin 2 disengages from the smaller portion 141 of the safety oil discharge hole 14 and therefore, the hydraulic circuit is a closed circuit. This means that the hydraulic oil can circulate through the safety oil discharge hole 14, the axial hole 41 of the adjustment screw 4, the annular slot 11 of one-way valve 1 and return into the oil storage tank, allowing the pressure inside the jack to be depressurized. When the pressure inside the hydraulic jack decreases to within the safety load limit, the force from the safety spring becomes higher than the internal hydraulic pressure of the hydraulic jack, and therefore, the safety spring 3 automatically biases the push pin 2 forward so as to seal off the small portion 141 of the safety oil discharge hole 14. By this setup, the safety of the hydraulic jack can be assured and an explosion can be prevented. In addition, the push pin 2 is a linear fluid guide inside the safety oil discharge hole 14. When the latter is discharging, turbulence is prevented and a smooth operation can be assured. It is indeed a compact, practical and modern design.

By use of the above configuration, the flow of the hydraulic oil is described as follows: when the lever 5 is pulled up, the hydraulic oil inside the reservoir is sucked through an inlet 61 inside of the pump base 6. The oil follows the L-shaped oil inlet channel 12 and flows into pump 7. When lever 5 is pressed downwardly, hydraulic oil inside pump 7 is forced out through oil discharge hole 13 of the one-way valve. The oil follows an outlet path 62 of pump base 6 back into the pressure tank of the hydraulic jack so as to drive a piston up for lifting (now shown in Figure). However, if the lifting load of the jack exceeds the maximum design load and a user continues to operate lever 5 to force hydraulic oil into the pressure tank; the pressure could cause the pressure tank to crack or explode. Therefore, when the hydraulic pressure exceeds the safety limit, the improved safety valve structure, according to the present invention, allows the hydraulic pressure to push the push pin 2 inside the safety oil discharge hole 14 backwardly so that the hydraulic oil can follow the path through the annular slot 11 and through the inlet path 61 of the pump base and then return into the oil reservoir. Thus, the pressure inside the pressure tank can be controlled. In addition, the structure of push pin 2 provides a linear fluid guide so that the oil flow is smooth and accurate.

A hydraulic jack serves one fundamental goal: the lifting of heavy loads. Jacks are designed to provide force multiplication to enable a worker to amplify their strength through the jack"s hydraulics or mechanics to accomplish this goal.

There are two main types of jacks commonly in use; one type uses hydraulic pressure for lifting (hydraulic jacks), while the other uses a screw thread to achieve lift (mechanical jacks). Of the two, hydraulic jacks usually provide higher lift capacity and are more reliable.

Hydraulic jacks are available in two varieties: floor jacks and bottle jacks. Floor jacks have a horizontal shaft that pushes on a crank. The crank connects to a lifting pad that rises vertically. These jacks are capable of lifting several tons.

Bottle jacks have been around longer, and their name derives from their resemblance to an old-fashioned milk bottle. Bottle jacks have a vertical shaft that raises a platform called a bearing pad. They can lift up to several hundred tons, depending on the specific capabilities of the model being used. However, these jacks typically cannot lift the load to the same height as with a floor jack.

Both types of jacks operate under the same basic principle: In a closed container, the pressure is the same in all directions. In the case of a hydraulic jack, this container is a cylinder, and it holds incompressible hydraulic fluid. Hydraulic fluid is forced into the cylinder through a check valve that prevents the fluid"s backflow. The check valve keeps the cylinder pressurized so the load does not drop. As pressure builds in the cylinder, the force pushes upward on the plate of the jack and lifts the load resting on it. The weight of the load lowers the plate when the check valve is released, allowing the hydraulic fluid a path to exit.

There are some issues that are common to all types of hydraulic jacks which can impact their operation and safety. At some point, users will likely encounter leaks, rams that won’t lift, safety valves that get tripped, damage to the frames, and jack handles that kick back. While many hydraulic jack repairs are easy to accomplish, others might require the assistance of a professional.

Leaks, in particular, are extremely common, and result from a failed or dislodged seal or O-ring. Repair involves draining the hydraulic fluid, disassembling the jack, and inspecting the seals. Be sure to look carefully for cuts, tears, seals that are out of place, degradation, scratches, and so on. These issues are an indication that the seals or O-rings need to be replaced.

Repairing leaking seals can be a significant undertaking, especially for those not experienced in jack repair. Novices might want to leave this type of issue to a professional with the requisite experience. Also, if the leaked fluid is cloudy or foamy, that indicates the presence of water or air in the hydraulic system and could mean that the hydraulic fluid needs to be replaced and the potential source of the intrusion investigated.

Jacks may also be overloaded, causing the safety valve to trip. The purpose of this safety feature is to prevent the jack from being loaded beyond its rated operating pressure, typically measured in pounds- force per square inch (psi). A jack will not behave the same way after the safety valve has been tripped. The ideal way to address this issue will vary by manufacturer, so always consult the service manual when this occurs. Professional service is recommended in these instances to restore safe operation of the jack.

In other cases, rams may stop lifting, which is usually the result of insufficient hydraulic fluid in the reservoir. Luckily, this is a repair that even beginners can handle. When there isn’t enough hydraulic fluid present, air may become trapped inside of the system. The solution here is to add the appropriate amount of hydraulic fluid, then turn the jack to its release position. Next, pump a few times to purge out the trapped air. Then, refill the reservoir and place the seal cap back on. Be careful to avoid introducing contamination (such as dirt and dust) to the hydraulic system while adding fluid, and never mix two different types of fluid.

Hydraulic jacks are powerful devices for lifting, but like any other mechanical or hydraulic system, they will inevitably require maintenance and occasional repairs. While someone with fundamental mechanical skills may accomplish some repairs, others are best handled by a hydraulic professional. Be sure to consider the options carefully before deciding on a course of action.

... assemble/disassemble Handle supplied with a small hook to get from under the vehicleIdeal to be used in combination with the CP jack standsThis product is not marketed yet in North America and Australia.

... lowered roll can be brought up easily with the pressure relief valve. You can easily adjust the equipment with the handle on the jack. There is a powerful piece of equipment that will help you to lift the loads.

... hydraulic jacks is very simple. Jacks are supplied ready for use, i.e. including hydraulic oil, operating lever and, where applicable, carrying handle and lifting claw.

... multitude of modifications on our jacks to suit any pit! Please complete a Pit Survey form for an accurate quote. We also offer Distributor rates if you wish to become a re-seller please contact us for more information.

ECO-Jack® heavy duty hydraulic jacks are available in five different series with payloads up to 25 tons. The adjustability of the lifting claw on all ECO-Jack® is patented ...

ECO-Jack® heavy duty hydraulic jacks are available in five different series with payloads up to 25 tons. The adjustability of the lifting claw on all ECO-Jack® is patented ...

The ECO- Jack S Series is composed of hydraulic machinery toe jacks from HTS Hydraulische Transportsysteme GmbH. They can lift heavy loads like tools, machines, and dies that follows ...

The hydraulic jack allows you to unwind the cable ( pay-off ) from drums with safety. You can use it in combination of a winding a machine or using it for cable installation.

The hydraulic jack allows you to unwind the cable ( pay-off ) from drums with safety. You can use it in combination of a winding a machine or using it for cable installation.

The hydraulic jack allows you to unwind the cable ( pay-off ) from drums with safety. You can use it in combination of a winding a machine or using it for cable installation.

Complete range of suspended or floor pit jacks. Ergonomic and modern design with work-height control-panel. The 2 individually controlled rams offer safe and balanced lifting.

For lifting of machines and other heavy loads. Easy lifting with lifting claw and end plate by means of installed hydraulic hand pump. Precise lowering via lowering valve, overload valve. Pump lever detachable. Swivelling ...

In order to learn more about the process of designing a part, group 10 took apart a Big Red car Jack. The device is designed to use hydraulic fluid and one-way valves to raise a ram rod so as to lift 4-ton vehicles in order for the user to be able to change tires. The jack is operated using a removable handle, which is pumped up and down, raising the jack, which in turn lifts the car.

After testing and dissection, we concluded that the jack was both easy to use and very compact. The jack did not take very long to achieve the desired result and required minimal energy to use. In order to get a better understanding of the jack we performed Failure Modes and Effects Analysis (FMEA), Design for Manufacture and Assembly (DFMA) and Design for Environment (DFE).

FMEA allowed the group to get a better understanding of the failure modes and the impact the failure modes had on the user. One possible failure mode is the jack could slip from under the car causing the elevated car to fall on the user.

DFE showed the group the environmental impact of the jack. EIO-LCA (Economic Input Output-Life Cycle Analysis) was used to see the greenhouse gas emission over the lifetime of the product in the various sectors of the US economy. It was concluded that the production of the hydraulic fluid had the largest percentage of Carbon.

The main stakeholder for this product is the consumer. The consumer is the main person operating the device and is the one who will suffer the most if it fails. Cost, reliability and safety are a few of the needs the consumer has from the product. However, the consumer isn’t the only group that this product has an impact on. Retailers, manufacturers, and Shippers/transporters also have interactions with the product.

The Big Red Hydraulic Bottle Jack can be operated with everything in the packaging. It does not need any additional fluid, or an electrical source. The eight-pound jack can lift vehicles weighing up to 4 tons simply by moving a handle up and down. Once the vehicle is lifted the jack can maintain the car at the required height to change a tire. To compensate for different size cars, a worm screw is attached at the top tat can extend upwards to assist in the lifting of cars that are taller.

When the group tested the jack, without using the instruction, we found the jack very confusing. However, once we read the instructions and tried operating it, we discovered that the jack was in fact very easy to use. Although it was easy to use, there were some problems with the jack. It had trouble getting under smaller cars, which is understandable since it is designed for 4-ton cars. Also pumping the handle was challenging since the user had to kneel on the ground and lift the handle once it was lowered to pump it repeatedly. The release screw was also difficult to rotate by hand. However, with the handle bar inserted, the task became easier, but still challenging.

One of our group members gave the jack without instructions to another Carnegie Mellon student and had them jack up their car. Without help, the person also struggled initially using the jack, but ultimately decided that the jack was very compact and easy to use.

After doing research and self evaluations on the jack, the group has concluded that the item is very compact and light for a jack. The group also concluded that its size makes it very easy to store in a car and the design makes the jack very easy to use. Since there aren’t very many exposed moving parts and there is not combustion, the jack is fairly safe. Its steel design also makes it very robust and hard to damage. Some of the corrections the group would make is possible widening the base to prevent tipping as well as improving the handle to prevent it from getting lost. Also allowing the jack to work for a larger variety of cars cold be another improvement.

The following is an exploded view of the hydraulic jack. The parts each number corresponds to are listed below the picture and in the Bill of Materials section.

The following is a list of the 31 parts that make up the hydraulic bottle jack. Most pieces are made of steel, that has been shopped in some way, usually on a mill or a lathe. The non steel parts are either rubber or plastic and are purchased or injection molded. The table can be sorted by Part Number, Quantity, Weight, Material, and Manufacturing Process.

The jack is made up of a series of concentric cylinders each of which is pressurized and holds differing amounts of hydraulic fluid. When the handle is inserted into the pump mechanism and moved up and down, fluid is pumped from a reservoir in the outer cylinder into the space in the bottom of the inner chamber, pushing the ramrod shell upward. This fluid is kept inside the inner cylinder by a high-pressure valve located in the base of the jack, consisting of a check valve and a debris filter to keep unwanted solids from breaking the seal created by the ball bearing. The jack can be released by loosening the valve screw at the jack’s base, thus allowing the fluid to return to the outer cylinder until the valve screw is tightened again. This release of fluid will then lower the ramrod shell, lowering the car and allowing the jack to be removed. The ramrod also has a section that can be unscrewed, providing extra length to the mechanism.

Chanshu Tongrun Auto, the company that manufactures this particular product, produced roughly 10 million car jacks in 2010 [1]. As a result, the jack is made with two primary design goals: sufficient strength to lift 4 tons of material off the ground and simple, easily mass-produced parts.

Nearly all of the parts in the hydraulic bottle jack are either machined from steel stock or purchased from other suppliers, with the exception of the cast steel base and end cap. Most of the machined steel tubes appear to have been turned on a lathe in a job shop, but given Changshu Tongrun"s incredibly high output, they were probably made in some sort of automated process.

Standardize ComponentsBearings, connector pins, O-rings and washers appear to all be purchased in bulk, and can probably all be used for the different jacks that Chanshu Tongrun producesEnsure most parts are made of similar diameter pipe to the same parts used in other size jacks, to make part purchasing easier

After considering all of our system components, we identified eight major areas where our product could fail. Most of the major areas are made up of external components of the product, parts which the user interacts with while he/she operates the system: the handle assembly, the pump structure, the base, the extended screw, the alligator clips, and the valve screw. Unless the product is dissected, the remaining areas cannot easily be reached.

Even though the probability of failure of the internal components is low, their severity and detection of failure are very high. If these parts needed to be replaced it would be extremely difficult for the user to take the system apart. We recommend a design that makes these parts more accessible. That way elements such as the hydraulic liquid and parts can be changed when needed. This will allow the user to maintain the jack which will guarantee safety and durability.

BaseTips OverCar falls causing injury to the user and/or damage to the vehicle.10The jack is not properly placed under vehicle. The user does not place car supports after lifting. An uneven surface does not provide stability.4Position jack under a flat surface of the car, place supports, don"t work on uneven ground.9360Change the shape of the base, more surface area. Make a multifunctional package to use as support for base.

Valve ScrewRemoved, LeaksLoss of hydraulic fluid. Balls bearings can fall out of place.9User unscrews the valve all the way out.6The manual instructs user on how to close and open valve.5270Place a stopper in the inside to prevent user from turning the valve further once opened.

Extender ScrewPlaced on an uneven surfaceCar may slip and screw bend8Jack is not properly placed under vehicle.4Position screw surface area under a flat area of the vehicle.8224The shape of the contact area could be altered.

Handle AssemblyInner and/or outer handle bends.Cannot properly pump the car jack.7Misuse or damage by customer.4Do not overload the material. Store it in a safe place8224Design a rigid handle with a high Young"s Modulus to resist deformation.

The inner and outer handles separate.Pumping the car jack becomes difficult and can lead to injury.3The user pulls while pumping which causes separation.7While pumping make sure the outer handle does not slip out of place.5105Design a handle assembly that locks the inner and outer handle.

O-ringsWear leads to breakageLoss of hydraulic liquid10Wear2If the jack has not been used for a while or has been used for years, test that it works before lifting a vehicle.10200Change system so it"s easier for the customer to notice and maintain.

Plastic BumperGets out of positionOne of the ball bearings will fall out of place.10Wear or lack of lubrication, can cause plastic part to break and pop out of place.2The hydraulic liquid is a multifunctional component that provides lubrication.10200Allow the user to add liquid to the system if liquid lost.

One of the components bends.Cannot properly pump the car jack.7Misuse or damage by customer.3Limit the force applied to these components.8168Use a rigid material to resist deformation. As a customer prevent damage by using the product appropriately.

This section discusses the major sources of greenhouse gas (GHG) emissions associated with this product, shown in detail in the table below. The largest source of GHG emissions from this product is the use of hydraulic fluid in the jack. This fluid is a petroleum product and is therefore made up of a large percentage of carbon. If congress were to pass a tax on CO2 emissions, the cost of the hydraulic fluid would be likely to increase, therefore increasing the initial cost and cost to maintain the jack. Cost of manufacturing the jack itself would also increase, but not so significantly as that of the fluid. That being said, overall the cost of both the jack and an initial fill of fluid is unlikely to increase by more than a dollar, so it wouldn"t have a major impact on the sales of the jack. It is important to note that there are also GHG emissions associated with disposing of the jack. Because the fuel is petroleum based, it will release CO and CO2 into the environment as it decomposes. Recycling the jack would be a better option because you could safely dispose of the fuel and reuse the steel. Additionally, GHG emissions from the hydraulic fluid could be cut down by using a more environmentally friendly fluid such as a vegetable oil based product[3] or by choosing a fluid that does not need to be replaced so often.

Another area where GHG emissions can be reduced is in the manufacturing of the jack. Already many parts of the jack are manufactured by processes with relatively low energy intensity. Most notable are the parts made by stamping and bending sheet metal, which are processes requiring relatively low energy input. The manufacturing of many other parts of the jack, such as its inner cylinders, seem to have been produced by an automated lathe machine. These processes can be designed to reduce energy usage by minimizing machinery necessary for their production.

Assumptions*30 year lifetime*Jack is frequently used and maintained *Replaced oil every 2 years [4] *Oil costs $5 for 32oz [5]*Oil is petroleum based and therefore 85% carbon [6] *all of the carbon ends up as CO2*assumed it costs $360/ton of recycled steel [7]

If hydraulic fluid is changed every two years as recommended, then it is clearly the biggest source of CO2 emissions. However, if users rarely or never replace it, then CO2 emissions from the fluid will be on about the same scale as those from the other sources.

Many jacks use the ball bearing against a seat in order to reduce alignment problems inherent in any manufacturing operation. Many jacks have been ruined by gorillas tightening the release valve and deforming the seat etc. My own floor jack was ruined last year by a "helper" that grabbed the jack and gave the handle a twist before I could stop him. I have not looked into repairing it yet. HF and many other stores will re-box returned items and place them back on the shelf. It may be that you got someone else"s gorilla tightened jack return.

A hydraulic shop press is a type of machine press that uses a cylinder in order to create a compressive force. The force of the shop press can be used for a variety of jobs such as clinching, moulding, forging and metalworking; it also has the ability to create a variety of intricate shapes for mo

This is a 1 1/4 ton hydraulic floor jack my father passed on to me.  He bought it new during the 1970s. It began to leak down a little a few months ago. The lift arm no longer rises when the handle is pumped up and down. (I was able to pull the lift arm up by hand and it settled slowly enough that I could make a photo with the arm partially raised.)

I checked to be sure it was adequately filled with fluid, but that was not the problem.  A few months before this problem, there were bubbles coming up through the vents at the filler plug.  At that time I raised the lift arm with the handle, released the jack"s valve, and let the arm fall slowly several times to purge air from the system.  Finally, one day, the lift arm would not rise at all. If filling with fluid and purging air from the system do not restore function, there is probably internal leakage, even though fluid is not leaking from the jack.  From what I have read, forty years of service is a reasonable time for a hydraulic jack to operate before it needs a rebuild.

A word of caution: Rebuilding this jack presented several challenges that seemed almost insurmountable at the occurrence of each.  Rebuilding this jack was much more difficult than simply replacing a few "O" rings, and it required more than the very few hours some say are required for rebuilding a jack. Further, I had to make several special tools to get the job done. If you want to attempt rebuilding a jack and you are not a member of Instructables, I would encourage you to pick a password and a screenname, and join.  Doing that will allow you to download a PDF of this Instructable for printing, or to view at any time later on your computer, assuming you wish to consult what I have done as a guide.

When putting fluid into a jack never use anything other than hydraulic jack fluid.  Do not use motor oil or brake fluid. Brake fluid makes the seals swell.

At this link you will find one man"s description of how he rejuvenated his twenty-five year old jack by flushing its insides with a solvent, letting it dry completely, and filling it with fresh hydraulic jack fluid. It could be worth a try. I did find one manual for a floor jack that said the fluid should be changed every year. The procedure is to place the jack over a large pan, remove the filler plug, turn the jack on its side and let it drain. Then fill it again.

Several firms sell rebuild kits for hydraulic jacks. I found Blackhawk Parts and ordered parts on-line. My jack came with the Fleet brand name. It was sold through NAPA Auto Parts.  It should have been easy to find my jack among the listings for Fleet jacks on the Blackhawk Parts web page and order the appropriate rebuild kit, but it was not.  So, I sent an e-mail to Blackhawk Parts with the name of the manufacturer and the model number.  It is good that I did.  The kit I need is not the one I would have thought, but is actually for a Lincoln/Walker jack. Although my jack has the Fleet name, it was actually made by someone else.  I paid about $45 for the parts kit, plus $11 shipping. That is a fairly typical price for a rebuild kit.

I decided not to open the parts kit until I was certain the parts it contains match what I see on my jack as I dismantle it.  I will have less difficulty exchanging an unopened parts kit than I would have trying to exchange a kit I had opened, in case the wrong one was shipped to me.  In the photo you can also see the paperwork that came with the parts kit.  It will help, too, if an exchange were necessary.  And, I do not want to risk losing any parts by opening the bag early and having something roll out.

The rebuild kit does not include any instructions.  The Blackhawk Parts web page offers a few cautionary and a few safety notes, but no helps on the rebuild procedure for the Saturday mechanic. e-How does offer a step-by-step procedure for rebuilding a hydraulic jack in text, but it is quite general. There is avery helpful link at the e-How page that takes you to a set of photos and some useful notes on critical stages for doing work on a low price imported hydraulic floor jack. Some of these things would be very helpful for the proper assembly, too. Floor jacks are remarkably similar, despite small differences. See the next step for information on helpful videos on-line.

The graphic for this step is an exploded diagram of a hydraulic jack and a list of parts.  This one is from aHarbor Freight jack. Diagrams like this one are easy to find on the Internet.  Just search for "hydraulic jack manual."  Diagrams like this one help with the names of parts and with a visual understanding of how the parts fit together. You can enlarge images in your browser to see more detail, or save them in PDF and do the same. But, if you are able to watch the videos linked in step 3, you will see how the parts fit together, too. (The day may come when those videos are no longer available on the Internet.)

There are many videos related to hydraulic jacks at YouTube, but most of those are not really very helpful for a rebuild, even though their titles are enticing.  A floor jack is a really a bottle jack laid over onto its side and installed inside a frame equipped with casters, a handle, and a lift arm. This video shows how to remove the bottle jack unit from the frame. The floor jack in the video is my Fleet jack with a different name and paint color on it.  Some jacks are the least bit different.  You may also want to view this video.

If you do not want to rebuild the bottle jack unit yourself, you can use either of these videos to remove the bottle jack unit from the frame of the jack and simply take it to a repair shop near you.  The cost of a rebuild at a shop is said to be around $150 to $200 plus parts. The e-How article linked in step 2 contains a word of caution. If your jack is a cheap import, it may not be worth a rebuild.  The machining is not always as good as on the older models made in the USA. Further, the correct parts kit may be impossible to get. You may find it more economical simply to buy a new jack.  Classic jacks made in the USA are generally considered worth the expense and effort of a rebuild.

First photo--The halves of the jack frame will need to be spread to get the bottle jack unit out for repair. Loosen the nuts on the axle for the lift arm considerably, but do not remove them. There is one on each side of the jack frame. The nuts on my jack are 15/16 inch in size.

Second photo--Two bolts on each side hold the body of the bottle jack unit to the frame.  Remove all four. (One is partially backed out already.) Although the man in the video from step 3 removed the casters, that is not really necessary to access the bolts on this jack. I did fine without removing the casters.

Fourth photo--A universal joint twists to open and close the release valve. The upper end of the universal joint is a piece of hex stock. It fits into a hex socket in the bottom of the handle.

Fifth photo--Lift the jack frame and the bottle jack unit remains on the work surface, even though attached to the lift arm by hinged extensions. Use a pair of pliers to remove the end of the return spring from the pin.

Sixth photo--The rams from the jacks shown in the videos attach to the frame with a cotter pin.  On this jack a pin both holds the end of the spring and secures the block in the photo to the top end of the ram.  Flip the bottle jack unit over and drive the pin most of the way out with a hammer and a punch.

Place the bottle jack unit into a pan and drain the oil as best you can. On the bottle jack unit in one of the videos it was easy to work the plunger in order to extract more of the oil. The spring on the plunger is too strong for that on this jack.  Be aware that additional oil will pour out of the jack in coming steps. Have a pan or newspaper available to catch it and minimize the mess.

The first photo shows the ram and ram nut (or tank nut, also top nut) at the end of the bottle jack.  Most ram nuts are hexagonal.  This one has two slots for a special spanner wrench.  In the video from step 3 showing a man taking the ram nut off of a bottle jack, the ram nut came loose quite easily.  On my jack the nut was stuck on very hard.  I placed the bottle jack unit into my vise and tried to loosen the ram nut with a very large pipe wrench.  I only did a little cosmetic damage to the nut. It would not loosen.  I soon realized that my workbench and vise were not equal to the task, either.

The third photo shows the tool in use.  Check the yellow text boxes.  My vise did not have enough leverage to hold the bottle jack unit, so I bolted it upright into the jack frame and used the jack frame as my own long bar for leverage. In order to make that work, I planted my foot against the end of the frame that is not shown in the photo. I had to strike very hard with a 16 ounce ball peen hammer, but after about five or six strikes, the ram nut began to move. My tool worked and I was able to loosen the ram nut with the ram for removal from the bottle jack unit.

First photo--Unscrew the ram nut until it and the ram can be pulled from the bottle jack unit.  The ram nut simply pulls off of the top end of the ram.

The outer shell of the oil tank appears to be securely fastened to the base of the bottle jack unit, but it is not. Press against its side and it tips off to one side immediately. There will be some oil that runs out onto the work surface. Put down some newspaper or a pan to catch it.

Third photo--Unscrew the universal joint assembly for the release valve. Insert a magnetic tool and pull out the cone-shaped plug.  The hole from which it came is visible behind the magnet tool.

Fourth photo--Place the bottle jack unit in a vise and use a wrench to remove the plunger mechanism. I had to tap on the end of the wrench with a hammer to loosen it. On my jack a 1 inch wrench was required.

Move your cursor over the text boxes in the first photo. for part names, etc. The cylinder would normally be removed for a rebuild. But, this one is stuck very tightly. Remember how much difficulty there was in removing the ram nut in step 6. It screws to the cylinder, so the cylinder should be difficult to remove, too. It is not as easy as the video linked in step 3. I tried, but could not get it to loosen. There actually are no "O" rings or seals below the cylinder on this jack.  Removing it does not give access to any removable parts. I did notice some oil at the bottom of the cylinder appears dirty.

There are two metal plugs in the body of the bottle jack unit. Two large screws are below them.  See the text boxes again.  This site warns NEVER EVER to open these. It also has a diagram of what is inside. (Scroll down to the middle of the web page.) The author"s concern is that the small balls in the valves can be lost, and the jack would become useless. Get a shallow cardboard box with no holes in the bottom or a large pan and work inside of either one. If any balls roll away, they will be contained inside the box or the pan. Also, extra balls are included in my kit. Even if the balls were not included in the kit, precision steel balls can be purchased at a bicycle shop in a series of sizes. Check the link in this paragraph for the sizes normally used. The ball sizes in my jack are: 5/16 inch (7.94mm), 7/32 inch (5.55mm), and 5/32 inch (3.96mm). I measured them with a caliper through the plastic parts bag. I want to do as complete a rebuild as possible. Dirt may have found its way into the passageways where the balls are. The balls could also have rough surfaces through years of use.

If I turn the jack body back and forth I can hear metal balls rolling inside passageways.  I drilled a hole in the center of each of the metal plugs.  Then I inserted a slightly larger sheet metal screw into the hole until the threads bound against the hole I drilled. I placed a pair of pliers under the head of the screw and pounded against the pliers with a hammer to pull the metal plug out of the jack"s body.  I repeated the process with the other plug. New plugs are included in the parts kit.

The second photo shows the bottle jack unit"s body, but inverted so it was easier to hold while operating the camera.  The metal plugs have been removed. Both holes have a large screw inside them.  The one on the right is recessed so far that it is not visible.  It is the safety overload valve.  This valve protects the jack"s seals from failing under a load heavier than the jack"s rating.  When the safe range of the jack is exceeded, the safety overload valve opens like a pressure regulator to allow oil to return to the tank rather than entering the chamber for the ram. This screw has to be set so the safe level of pressure is not exceeded. In order to do that at home, I carefully turned this screw and counted by half-turns until it bottomed out.  My screw was set to 1 3/4 turns above or looser than the bottoming out point. When it is time for reassembly, I will turn the screw gently until it bottoms out, then I will back it off 1 3/4 turns. The safety overload valve should then be set very close to the original factory calibration.  One author noted that some jacks fail because the safety overload screw unscrews itself, which sets the jack"s lifting ability to a much lower threshold, and the arm may not lift what you want to jack. I found this screw turned with enough resistance that it is not likely to shift its position by itself. That same author also said most safety overload screws are about two turns looser than the bottoming out point.

The fourth photoshows another special tool I made.  The screw for the check valves is quite tight.  I tried the largest screwdriver I had (3/8 inch wide blade) with a wrench on its square shank.  The blade on the screwdriver broke! The screw slot is 1/2 inch across the diameter of the screw and almost 1/8 inch wide. I bought a short bolt 5/8 inch in diameter.  It is #8 on the hardness scale. Near the end I ground the diameter down until it fit nicely inside the recess for the screw.  I kept a cup of cold water near my grinding wheel to avoid softening the bolt with heat. I ground a rough profile by sight. I moved the bolt to a vise and finished cutting the profile of the screw slot by means of a hand file. I checked the dimensions with a digital caliper.  When my improvised screwdriver fit the screw and its slot, I tapped on the bolt"s head to be certain it had fully seated in the slot.  I used a wrench on the bolt head and the screw came out with no difficulty, at all.  I had tried to buy a large screwdriver, but could find none this large.  This improvised solution cost me $1.65 for the bolt and a few minutes of time.

The first photo shows a paper towel I pressed into the cylinder and rotated with a screwdriver without letting the screwdriver touch the sides of the cylinder. (Be careful not to scratch the inside of the cylinder.  A 1/2 inch dowel pin would have been a safer tool to use.)  Jack fluid is clear.  The towel shows how much dirt was in my jack"s oil.  In addition to sopping up some dirty oil still in the cylinder, I poured a little clean jack oil into the openings and passageways.  Most of it collected in the opening for the plunger.  At first this oil was cloudy. After a few tries, it was clear. I think this should adequately clean the jack so that it can be reassembled.

Inspect the seats in the bottle jack unit"s body for signs of rust and pitting.  The seats need to be clean and smooth.  When I let sunlight shine into the recesses where there are seats, I saw more dirt.  I used a wooden dowel rod to scrape and break loose any dirt I could find.  I poured some jack oil into the holes to flush the dirt away.

Second photo--Clean the groove that receives the tank"s outer shell. It has some brown dried oil residue. Something brass would be ideal.  It would be tough enough to remove the residue, but would not scratch the machined surface. Someone said jack oil is a vegetable oil. The oil residue is certainly like what I have seen in the kitchen from vegetable oils.

I kept the bag of parts inside the same shallow pan in which I assembled the bottle jack unit.  This is so I am less likely to lose parts, especially the steel balls.

First photo--This shows the plunger body and the plunger parts.  At the left three leather seals are shown.  My jack does not use these. Several different parts came in more than one version. I think the same parts kit is sold for several similar, but different jacks. I have some parts I will not use on my jack.  In the center area of the parts are the steel washer and the locking nut. The other two parts at the right are the old seal I removed.  It has an oily sheen. Just below it is the replacement part my jack requires.

Second photo--Coat the new neoprene seal with fresh jack oil. During the installation of all parts, double check for any grit or dirt sticking to the oily parts and remove it before the installation of that part. Install the new neoprene seal, rounded end first.  Install the steel washer and the locking nut.  I will discuss how tight to tighten the locking nut after treating how to install the spring assembly onto the plunger body. I made a special tool for putting the plunger assembly back together. It is made from steel wire about 1/8 inch in diameter. The wire came from stubs of concrete reinforcement wire broken off from a friend"s foundation for his new garage.

Check the plunger for dust and particles of wood. Thread the plunger into the base of the bottle jack unit. Tighten with a wrench and hit the wrench several times with a hammer to make a good seal, since there is no "O" ring or copper washer to make the seal.

First photo--I have a dental pick I can use to remove old seals. This "O" ring shows cracks from age when stretched a little.  Match the new "O" ring from the parts kit to the old "O" ring.  Coat it with jack oil.  Install the new "O" ring.

Second photo--Install the conical metal seal in the hole for the release valve.  The pointed end goes in first.  Tamp on it with a small screwdriver to make sure it seats at the bottom of the hole.  Thread the release valve into the hole.

First photo--The hole for the check valves has a copper sealing washer inside it.  The old washer is barely visible in the hole.  Note its color.  A new copper washer is supplied in the parts kit.  The old washer has compressed to fit very tightly.  There is no good way to remove it.  I did not want to fill the passageways in my jack with copper shavings from digging it out in pieces.  I decided simply to place the new washer on top of what is left of the old washer.  (This photo was made before the plunger and the release valve were installed.)

Second photo--Install the parts in the order shown in this photo from step 8. (The release valve and the plunger are not shown in this photo.) Use the new balls from the parts kit. Do all of this inside a pan or shallow cardboard box so none of the balls are lost if one gets away from you. Tamp the parts down with a small screwdriver so they settle down as far as possible in their hole. Carefully start the screw plug with a screwdriver. It is easy to crossthread. Use the special screwdriver made from a hardened bolt to tighten the screw plug with a wrench.

Third photo--Install the parts shown in this photo from step 8. Drop the new ball into the hole. Insert the spring into the open end of the cap and drop both into the hole.  Insert the screw plug. Carefully turn the screw plug until the valve assembly bottoms out.  Back it off 1 3/4 turns.

I chose not to install the metal plugs that close the valve holes yet in case I would need to open one of the valves during testing of the jack to correct a problem.

Coat the inside of the cylinder with jack oil before inserting the ram. You should be able to pull the ram up and push it down with your hand. A seal too large in size makes the ram very difficult to install and to move.

Second photo--Clean the tank shell, both on the edges that mate to make a seal and inside. I found quite a bit of dirt inside mine. The dirt had not entered the jack from the outside, but appeared to be residue that had formed from changes in the oil.  I applied some jack oil to the inside of the tank and wiped it with a clean paper towel. I did this several times until I could no longer feel anything gritty with my fingertips.

Retrace what you did in step 4, but in reverse, to bolt the bottle jack unit back into the jack"s frame.  (The photo is from that step.) While the bolts are still loose, put the handle"s yoke in place.

I used about 20 ounces of jack fluid. Around 12 ounces was used to fill the jack. The rest was used for cleaning and flushing the bottle jack unit. The fill hole is 1/4 inch in diameter.  Even though the bottles for the jack oil have a pointed end, some spurts out while trying to get the bottle end to the hole, and it makes a mess. Get a funnel with a very narrow end.  This is one I made specifically for this job from some sheet metal.

I filled the reservoir in small steps. The jack"s release valve was open. Occasionally I pumped the yoke for the handle.  When oil was at the level below the plug hole, I pulled the lift arm up and let it fall two or three times. This is to draw oil through the jack. I pumped the yoke between five and ten times to remove any air lock in the check valves.  I checked the oil level again a couple of times. Then I returned the reservoir cap.  The reservoir cap appears to be open, but actually has a small felt filter inside it.

Update: After using my jack a few times, it tends to throw off extra oil through the felt filter in the reservoir cap. I do not have the original instructions for this jack, so I do not know exactly what the recommended fill level is for it. From what I have read, some jacks are to be filled to the bottom of the hole while the floor jack is level on a floor. Others vary between just covering the cylinder with oil to slightly below the fill hole. At first I thought I might have a leak, but it was just the jack throwing off extra oil. This extra oil may also be due to the jack evacuating air trapped inside the jack. There are bubbles in the oil vented. One source suggested raising the jack fully and lowering it slowly twenty or so times to remove all air that might be trapped inside the jack"s passageways. Check the oil level to keep it at the desired level.

My jack worked as it should immediately. The real test is to lift something heavy with the jack. I left the jack in this position for a few minutes. It did not leak down that I could see. Now I can use a hammer to tap the metal caps into the holes for the safety overload valve and for the check valves. I will check the fluid level again after I have used the jack several times. I will also watch for signs of leakage. It is also a good idea to oil or grease all moving parts on the jack now and regularly in the future.

Troubleshooting--What do you do if you have rebuilt your jack, but it still does not work under load? Be certain the oil level is correct. Here are instructionson properly filling a floor jack. The jack could be air locked. This site says to open the release valve and pump the handle rapidly 10 to 15 times in that case. Here is a link to a document on troubleshooting hydraulic systems, like a jack. If necessary, check to be certain all check valve balls were installed properly. Check for leaks.

Conclusions--I did not find any clearly damaged seals in my jack, other than cracks in an "O" ring on part of the release valve, but it was a non-critical part. I did find dirt in the oil. I expect the seals were just old and less efficient. It feels good to have my jack working again, especially since it once belonged to my father. Rebuilding a hydraulic floor jack was much more difficult and a lot more work than I expected from information I had gathered before I began. I found some parts were not as easy to remove as I expected from videos and other helps that I linked earlier in this Instructable, and I had to make several special tools. I first had to develop those in my mind. Then I had to design them and build them with materials I already had. Fortunately, I have a welder and was able to do that without too much difficulty.

I can easily understand why many suggest a person ought simply buy a cheap jack and replace it with another when it fails. I have a hard time doing that, no matter how much financial sense it might make, That seems like the waste of a good tool containing numerous carefully machined parts. An imported floor jack comparable in capacity to mine lists for around twice the cost of the parts kit I bought, sometimes even less than twice the cost of the parts kit. I do not know if my Fleet jack will last longer than an import jack.

Knowing all I know now, I might suggest flushing out old jack oil every decade and replacing it with fresh, clean fluid. Even then, I am not sure draining the old fluid and refilling the jack with new fluid would have removed all of the dirt I found. Some of it was in places that seemed to hold the dirty oil in that particular place. The oil in the reservoir had always appeared clear and clean. Still, neoprene seals used in hydraulic jacks do harden or crack and will fail to seal properly in time.

Owning and using a hydraulic jack is often a necessity. But, it has costs over time. Those costs mean the eventual repair or replacement of a jack.  If you choose to repair your jack, you have the option of doing it yourself or of taking it to a shop.  If you choose to do it yourself, you will learn a lot, but it may require more of your time and be more difficult than you expected. If you take it to a shop, there will be a cash outlay that will likely be a fair amount greater than the cost of a new imported jack.

Several times I feared I had ruined a vital part on my jack, or was about to do so, simply because I was without knowledge and experience related to rebuilding a floor jack. It is my hope that this Instructable will enable others who wish to do so to rebuild a hydraulic jack with confidence and without some of the near mishaps I experienced. I wish someone had published this before I began to rebuild my jack. It would have saved me time and trouble.

Thank you. That is what I expected you have. I suppose you could also try to collect names of jacks using those gesrs and inquire of them to see if the gears are available as replacement parts.0

My CRAFTSMAN floor jack has 3 ports (valves)..... could you tell me what each one is and how to set them ? It was made around 2005...... (MADE IN CHINA) model #214.50145

I rebuilt this with new parts no problem...... I just did NOT check the turns for the check valve and safety overload valve and a 3rd one ??? ( factory settings) Any help would be greatly appreciated !

Thank you for your gracious comment. I hoped someone like you might see this and comment, especially in case I might have given totally false information, and you would correct me. This is my first intrusion into hydraulics, other than replacing a couple of brake lines on a previous family automobile and bleeding air from the system afterward. As I mentioned in the Instructable and in response to a previous comment, I needed to rebuild my jack; but, could not find all of the information I felt I needed. I wanted to document what I did, should I ever need it again, and also make it available to anyone else in the situation in which I found myself.

What would be your recommendation on the type of solvent to use and how long would let it soak inside the jack prior to rebuilding the 45+ year old hydraulic floor jack:

Ajack does not get hot and accumulate burned residue. Most parts will wipe clean with a rag. Sometimes there was residue where oil dried out. A wooden popsicle stick cut off square makes a good tool for removing oil residue without scratching the steel.0

There is one thing I learned that is worth knowing. Rebuild kits for hydraulic devices, even pneumatic devices, sometimes include two nearly identical O-rings, but one is slightly larger. One works, but the other does not. If an O-ring does not seem to fit, or the device does not seem to work, check for a nearly identical O-ring. A couple of years ago, my son-in-law rebuilt a nail gun. It did not work after rebuilding. He asked me to look at it. I replaced an O-ring with a nearly identical O-ring that was just a little different, and suddenly the nail gun worked just fine. I ran into something similar on rebuilding my jack.0

Very very good posting on rebuild of floor jack.Will be helpful with much detail for anyone wanting to complete a jack rebuild Thanks for all your suggestions, KneeWalker0

I understand. My life situation has changed. I am retired with a car that gets about all of its service at the dealership. We moved across the country and I left my floor jack with a brother-in-law. Here there is a son-in-law who will lend me a floor jack when I need one, but that has not happened. But, it is something you can check on your bucket list.More CommentsPost Comment

Hydraulic jacks simplify the movement of large or heavy items. The jack’s hydraulic system multiplies a worker’s efforts, enabling one person to successfully lift and maneuver heavy loads with little physical strain. Jacks are also used to suspend heavy objects in midair to provide maintenance access with minimal exertion on the operator’s part.

Though they’re built to be tough, hydraulic jacks can sustain damage from heavy use, improper maintenance, environmental elements, and other factors that compromise their ability to perform. Regular hydraulic jack repair and/or maintenance mitigates the damage caused by these issues by identifying signs of damage early and allowing for fast correction of any problems. This is especially crucial for older jacks that have been operational for many years.

Regardless of the type of jack or the application, there are some issues that are common within this tool category. Maintenance problems can compromise a jack’s ability to operate efficiently and negatively impact operator safety. If your equipment exhibits these signs, it is important to coordinate jack repairs right away.

Without a structural sound frame, your entire unit could literally fall apart under a heavy load. This type of damage typically cannot be repaired and requires the purchase of a new hydraulic jack.

Stop using your hydraulic jack immediately if the handle kicks back up after a down stroke. This condition is extremely dangerous for operators. Fortunately, a repair professional can restore the unit’s function.

When rams won’t respond properly, this usually points to a lack of hydraulic fluid. Simply add more fluid, turn the jack to its release position, pump a few times to release trapped air, and then refill the reservoir. Once the seal is replaced, the unit should function properly.

If the load is too heavy, the jack’s safety valves will engage, which will cause the jack to stop lifting. Refer to the user manual to identify the safety valve and follow instructions to reset it.

Hydraulic jacks are an essential part of many industrial and commercial operations. From warehouses to production floors, these devices enable the simple and efficient movement of massive products and components. However, hydraulic jacks are not indestructible. Like all machinery, attentive maintenance and prompt repairs are both key to prolonging the life of the unit.

Many common hydraulic jack repairs can be performed by novices or those with little mechanical skill. However, proper correction of many issues will benefit from professional input. Metro Hydraulic Jack Co. provides hydraulic jack repair services that support your commercial or industrial operation. Our repair shop and testing facility are fully equipped to evaluate, service, and repair your hydraulic floor jack.