wabco hydraulic pump motor failure 2 brands

After doing all the recalls/things they recommend, this is the most common reoccuring failure on the system and it occurs on buses built prior to Fall of 2006. If your bus is built before October (I think) of 2006, it has seal rings on the pumps which are made out of a material that can stick in the bore in the HCU if the bus is shut down and the piston is in the depressed position. Further, this happens after the bus sits for a while (like in the summer). If the failure is in the front pump, the bus will not move since the front pump is the one that supplies the pressure to the SAHR. If the rear pump sticks, you can release the brake with a laptop and Wabco Toolbox software and drive it to the dealer. Now, the good news! Wabco has extended the warranty on these pumps (and the HCU) that were built before fall of 2006 to FIVE years! And, if you have a failure of one pump, they will replace BOTH under warranty (sometimes you have to get on the phone to Wabco yourself and wake up the call center dude though!). You didn"t mention the year or the exact conditions of the failure but this is the most common we have seen.

The other failure we see is harder to diagnose which is a bad motor in the HCU (only serviced as an assembly). Wabco has extended the warranty on the HCU as well on the above mentioned dates, but getting them to go for the HCU requires pulling teeth sometimes. They changed the way they constructed the motors after that date and to date, we have experienced no problems with the later models. The last one 2005 model I had replaced under warranty, I wound up paying ALOT to freight one in from Texas as there were none close by.

The best way to tell a pump failure is a "low pressure gradient" code and a "Pump monitor voltage low" code is usually an HCU if the rest of the electrical system is sound. Also watch out that the call center doesn"t try to get the dealer to bleed the system to get a stuck pump working. If the piston is causing the problem and they get it to work again (get the pump unstuck) it WILL break down again...usually on a Monday morning along with three other breakdowns! Just explain to the call center rep that the system hasn"t been opened up and thus....bleeding is not the problem...and the bus is in the problem date range for the pumps. There are no parts problems with getting the pumps (I have some). If the HCU is what they can"t find, good luck! Hope this helps. Let us know.

I (fixed) two other buses with this problem by tapping with a hammer. I have another that I pulled off the motor which is sealed and welded in the case so you can"t access the brushes/com to clean. I cleaned dry grease and rust out of the bearing port inside the modulator. The motor has a bearing on the end of the shaft that acts as an eccentric. It is working for now. I also did the service bulletin S10SG about drilling a hole in the motor. A bit too late I think they all were dry no water came out.

Embarassing personal experience has shown me that WabCo"s diagnostics currently only communicate via J1708/J1587. Make sure that the ToolBox program has J1708/J1587 selected & not J1939.

It selects HD Standard on the brakes under Brakes/Power Unit. Which is where I picked up the generic code for the mod motor. I try to manually load Wabco ABS Hydraulic and it gives me an error code. Tech support hasn"t got back with me yet. I read the D series just fine. The bus is fixed though. Should I drill a hole in it!?! :P

From what I have seen, I"ve been reluctant to tap on anything even in the vicinity of those valve bodies! I"m glad to know you can tap on the motor and get away with it, it can prove to be another diagnostic method, just to be sure I am chasing the right rabbit :)

Flint Hydraulics is dedicated to the worldwide distribution of original and replacement hydraulic pumps, hydraulic motors, and hydraulic replacement parts for heavy mobile and industrial equipment. Off-the-shelf availability coupled with the distribution center advantages Memphis, Tennessee has to offer give use the unique ability to provide hydraulic components across the globe, with same or next-day shipment in most cases.

An anti-lock braking system (ABS) is a safety anti-skid braking system used on aircraft and on land vehicles, such as cars, motorcycles, trucks, and buses.wheels from locking up during braking, thereby maintaining tractive contact with the road surface and allowing the driver to maintain more control over the vehicle.

In 1920 the French automobile and aircraft pioneer Gabriel Voisin experimented with systems that modulated the hydraulic braking pressure on his aircraft brakes to reduce the risk of tire slippage, as threshold braking on aircraft is nearly impossible. These systems used a flywheel and valve attached to a hydraulic line that feeds the brake cylinders. The flywheel is attached to a drum that runs at the same speed as the wheel. In normal braking, the drum and flywheel should spin at the same speed. However, when a wheel slows down, then the drum would do the same, leaving the flywheel spinning at a faster rate. This causes the valve to open, allowing a small amount of brake fluid to bypass the master cylinder into a local reservoir, lowering the pressure on the cylinder and releasing the brakes. The use of the drum and flywheel meant the valve only opened when the wheel was turning. In testing, a 30% improvement in braking performance was noted, because the pilots immediately applied full brakes instead of slowly increasing pressure in order to find the skid point. An additional benefit was the elimination of burned or burst tires.

The first proper recognition of the ABS system came later with the German engineer Karl Wässel, whose system for modulating braking power was officially patented in 1928. Wässel, however, never developed a working product and neither did Robert Bosch who produced a similar patent eight years later.

By the early 1950s, the Dunlop Maxaret anti-skid system was in widespread aviation use in the UK, with aircraft such as the Avro Vulcan and Handley Page Victor, Vickers Viscount, Vickers Valiant, English Electric Lightning, de Havilland Comet 2c, de Havilland Sea Vixen, and later aircraft, such as the Vickers VC10, Hawker Siddeley Trident, Hawker Siddeley 125, Hawker Siddeley HS 748 and derived British Aerospace ATP, and BAC One-Eleven, and the Dutch Fokker F27 Friendship (which unusually had a Dunlop high pressure (200 Bar) pneumatic system in lieu of hydraulics for braking, nose wheel steering and landing gear retraction), being fitted with Maxaret as standard.

Chrysler, together with the Bendix Corporation, introduced a computerized, three-channel, four-sensor all-wheelImperial.Lincoln Continental Mark III and Ford Thunderbird, as an option;General Motors introduced the "Trackmaster" rear-wheel onlyrear-wheel drive Cadillac modelsOldsmobile Toronado.Nissan offered an EAL (Electro Anti-lock System) developed by Japanese company Denso as an option on the Nissan President, which became Japan"s first electronic ABS.

1971: Imperial Archived 2020-02-04 at the Wayback Machine became the first production car with a 4 wheel computer-operated anti-lock braking system. Toyota introduced electronically controlled anti-skid brakes on Toyota Crown.Triumph 2500 Estates were fitted with Mullard electronic systems as standard.

1976: WABCO began the development of the anti-locking braking system on commercial vehicles to prevent locking on slippery roads, followed in 1986 by the electronic braking system (EBS) for heavy-duty vehicles.

1982: Honda introduced electronically controlled multi-channel ALB (Anti Locking Brakes) as an option for the second generation of Prelude, launched worldwide in 1982. Additional info: the general agent for Honda in Norway required all Preludes for the Norwegian market to have the ALB-system as a standard feature, making Honda Prelude be the first car delivered in Europe with ABS as a standard feature. The Norwegian general agent also included a sunroof and other options to be standard equipment in Norway, adding more luxury to the Honda brand. However, the Norwegian tax system made the well-equipped car very expensive, and the sales suffered from high costs. From 1984 the ALB-system, as well as the other optional features from Honda, was no longer a standard feature in Norway.

In 1985 the Ford Scorpio was introduced to the European market with a Teves electronic system throughout the range as standard. For this the model was awarded the coveted European Car of the Year Award in 1986, with very favorable praise from motoring journalists. After this success, Ford began research into Anti-Lock systems for the rest of their range, which encouraged other manufacturers to follow suit.

In 1988, BMW introduced the first motorcycle with an electro-hydraulic ABS: the BMW K100. Yamaha Introduced the FJ1200 model with optional ABS in 1991. Honda followed suit in 1992 with the launch of its first motorcycle ABS on the ST1100 Pan European. In 2007, Suzuki launched its GSF1200SA (Bandit) with an ABS. In 2005, Harley-Davidson began offering an ABS option on police bikes.

Typically ABS includes a central electronic control unit (ECU), four wheel speed sensors, and at least two hydraulic valves within the brake hydraulics. The ECU constantly monitors the rotational speed of each wheel; if it detects the wheel rotating significantly slower than the speed of the vehicle, a condition indicative of impending wheel lock, it actuates the valves to reduce hydraulic pressure to the brake at the affected wheel, thus reducing the braking force on that wheel; the wheel then turns faster. Conversely, if the ECU detects a wheel turning significantly faster than the others, brake hydraulic pressure to the wheel is increased so the braking force is reapplied, slowing down the wheel. This process is repeated continuously and can be detected by the driver via brake pedal pulsation. Some anti-lock systems can apply or release braking pressure 15 times per second.

The pump in the ABS is used to restore the pressure to the hydraulic brakes after the valves have released it. A signal from the controller will release the valve at the detection of wheel slip. After a valve releases the pressure supplied from the user, the pump is used to restore the desired amount of pressure to the braking system. The controller will modulate the pump"s status in order to provide the desired amount of pressure and reduce slipping.

This replaces the need to manually pump the brakes while driving on a slippery or a low traction surface, allowing to steer even in most emergency braking conditions.

A June 1999 National Highway Traffic Safety Administration (NHTSA) study found that ABS increased stopping distances on loose gravel by an average of 27.2 percent.

"ABS works with your regular braking system by automatically pumping them. In vehicles not equipped with ABS, the driver has to manually pump the brakes to prevent wheel lockup. In vehicles equipped with ABS, your foot should remain firmly planted on the brake pedal, while ABS pumps the brakes for you so you can concentrate on steering to safety."

The Insurance Institute for Highway Safety released a study in 2010 that found motorcycles with ABS 37% less likely to be involved in a fatal crash than models without ABS.

A toothed-wheel ABS sensor. These are the front brake discs on a BMW R1150GS. The toothed ABS ring indicates that this bike was manufactured before November 2002.

On a motorcycle, an anti-lock brake system prevents the wheels of a powered two wheeler from locking during braking situations. Based on information from wheel speed sensors the ABS unit adjusts the pressure of the brake fluid in order to keep traction during deceleration to avoid accidents. Motorcycle ABS helps the rider to maintain stability during braking and to decrease the stopping distance. It provides traction even on low friction surfaces. While older ABS models are derived from cars, recent ABS is the result of research, oriented on the specifics of motorcycles in case of size, weight, and functionality. National and international organizations evaluate Motorcycle ABS as an important factor to increase safety and reduce motorcycle accident numbers. The European Commission passed legislation in 2012 that made the fitment with ABS for all new motorcycles above 125cc to be mandatory from 1 January 2016. Consumer Reports said in 2016 that "ABS is commonly offered on large, expensive models, but it has been spreading to several entry-level sportbikes and midsized bikes".

In 1988, BMW introduced an electronic/hydraulic ABS for motorcycles, ten years after Daimler Benz and Bosch released the first four-wheel vehicle ABS for series production. Motorcycles of BMW K100 series were optionally equipped with the ABS, which added 11 kg to the bike. It was developed together with FAG Kugelfischer and regulated the pressure in the braking circuits via a plunger piston.Honda ST1100 and the Yamaha FJ1200.

Wheel speed sensors mounted on the front and rear wheel constantly measures the rotational speed of each wheel and delivers this information to an Electronic Control Unit (ECU). The ECU detects two things: 1) if the deceleration of one wheel exceeds a fixed threshold and 2) whether the brake slip, calculated based on information of both wheels, rises above a certain percentage and enters an unstable zone. These are indicators for a high possibility of a locking wheel. To countermeasure these irregularities the ECU signals the hydraulic unit to hold or to release pressure. After signals show the return to the stable zone, the pressure is increased again. Past models used a piston for the control of the fluid pressure. Most recent models regulate the pressure by rapidly opening and closing solenoid valves.

While the basic principle and architecture has been carried over from passenger car ABS, typical motorcycle characteristics have to be considered during the development and application processes.

Piston Systems: The pressure release in this system is realized through the movement of a spring-tensioned piston. When pressure should be released, a linear motor pulls back the plunger piston and opens up more space for the fluid. The system was used for example in the ABS I (1988) and ABS II (1993) of BMW. The ABS II differed in size and an electronically controlled friction clutch was mounted on the shaft instead of a plunger. Further displacement sensors record the travel distance of the piston to allow the control unit a more precise regulation. Honda also uses this system of pressure modulation for big sports and touring bikes.

Valve and Pump Systems: The main parts which are part of the pressure modulation system are solenoid inlet and outlet valves, a pump, motor, and accumulators/reservoirs. The number of the valves differs from model to model due to additional functionalities and the number of brake channels. Based on the input of the ECU, coils operate the inlet and outlet valves. During pressure release, the brake fluid is stored in accumulators. In this open system approach, the fluid is then brought back in the brake circuit via a pump operated by a motor that is felt through pulsation on the brake lever.

Different from cars or trains, motorcycle rear and front wheels are controlled separately. If the rider only brakes with one wheel, this braked wheel tends to lock up faster than if both brakes had been applied. A Combined Braking System therefore distributes the brake force also to the non-braked wheel to lower the possibility of a lock-up, increase deceleration and reduce suspension pitch.

With a single [rear] CBS the brake pressure applied on the rear brake (pedal) is simultaneously distributed to the front wheel. A delay valve cuts the hydraulic pressure to assure that only when strong braking is applied, the pressure is also created at the front wheel. Honda"s first street motorcycle with a combined braking system (then called Unified Braking) was the 1983 GL1100. This system was derived from the 1970s RCB1000 world endurance race bike.

CBS helps to reduce the danger of wheel locks and fall downs but in certain situations, it is possible that CBS causes a fall down. If brake pressure is distributed from the rear wheel to the front wheel and the friction of the surfaces changes suddenly (puddle, ice on the street) the front wheel might lock even if only the rear brake has been applied. This would lead to a loss of stability and a fall down. CBS is therefore combined with ABS to avoid this on a motorcycle.

In 2009, Honda introduced the electronic controlled combined ABS for its high-performance sports bikes which utilize brake by wire technology. The brake input of the rider is measured by pressure sensors and the information is provided to an ECU. Together with the information of the wheel speed sensors, the ECU calculates the optimal distribution of pressure to prevent lockups and to provide the best possible deceleration. Based on this output a motor for each wheel operates a pump that builds up and regulates the brake pressure on the wheel. This system offers a fast reaction time because of the brake by wire functionality.

The MIB (Motorcycle integral Braking system) from Continental Teves and the eCBS (electronic CBS) in the enhanced Motorcycle ABS from Bosch are results of another approach. These systems are based on the pump and valve approach. Through additional valves, stronger pumps and a more powerful motor the system can actively build up pressure. The input pressure of the rider is measured with pressure sensors at the lever and pedal. The pump then builds up additional pressure adjusted to riding conditions. A partial integral System is designed for working in one direction only: front→rear or rear→front. A fully-integrated system works in both directions.

Because these systems are electronically controlled and are able to build up pressure actively, they offer the opportunity to adjust the motorcycle braking behavior to the rider. CBS and ABS can be switched off by experienced riders and also different regulation modes with higher and lower thresholds can be chosen, such as the rain or slick mode in the BMW S1000RR.

The Insurance Institute for Highway Safety (IIHS) conducted a study on the effectiveness of ABS for motorcycles and came to the conclusion that motorcycles above 250 cm3 without ABS are 37 percent more likely to be involved in fatal crashes and a study of the Swedish Road Administration came to the conclusion that 48 percent of all severe and fatal motorcycle accidents above 125 cm3 could be avoided due to motorcycle ABS.

These studies caused the EU commission to initiate a legislative process in 2010 that was passed in 2012 and led to ABS for motorcycles above 125 cm3 becoming mandatory from 2016 onwards. Organizations like the Fédération Internationale de l"Automobile and the Institute of advanced Motorists (IAM) demanded the implementation of this legislation already for 2015.United Nations (UN) started the Decade of Action for Road Safety. The main goal is to save 5 million lives until 2020 through global cooperation.Electronic Stability Control and Anti-Lock Braking Systems in motorcycles.

ABS is required on all new passenger cars sold in the EU since 2004. In the United States, the NHTSA has mandated ABS in conjunction with Electronic Stability Control under the provisions of FMVSS 126 as of September 1, 2012.

UN Regulation No. 78, related to the braking of vehicles of categories L1, L2, L3, L4 and L5 (motorbikes) is applied by the European Union, Russia, Japan, Turkey, Ukraine, Australia and the United Kingdom.

Global technical regulation number 3 related to Motorcycle brake systems is applied by Canada, the European Union, Japan, Russia, and the United States.

From 1 January 2024, Argentina will require ABS on all new motorcycles from 250 cc, CBS (or front wheel ABS) for on-road between 50 and 250cc. Or their electric equivalents.