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Chris, Auto Service Technician
Category: Car
Satisfied Customers: 12586
Experience:  43 years of automotive repair, Smog license
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I have a 1996 Plymouth , Grand Vouyage. While driving the front

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I have a 1996 Plymouth , Grand Vouyage. While driving the front wheels start to shimmy and the car slows down due to brake drag. I disconnected the ABS and the problems still occurs. I recently installed new brake pads and calipers. What could be the problem ?

Welcome! My name is XXXXX XXXXX you for allowing me to assist you! Was the problem happening before you replaced the pads and calipers?



Customer: replied 3 years ago.


Ok Edward, then the problem is most likely a stuck ABS isolation valve in the Hydraulic Control Unit (HCU). Even though you disconnected the ABS electrically, that valve can be physically stuck in the HCU. Replace the HCU and bleed the system. That should fix this brake problem.


I hope this information helps, and let me know if you need further assistance with this.



Customer: replied 3 years ago.

If I open the system at the ABS can I bleed the system by depressing the brake pedal and opening the bleeder valve or does it require special equipment.

Yes you can bleed the system in a conventional manner like you normally do. However, the use of a scan tool to cycle the ABS valves is sometimes used to get any trapped air bubbles out of the HCU. If you do not have access to a scan tool that can communicate with the ABS controller, then what you can do is this: Do an initial bleed procedure. Then drive the van and slam on the brakes a few times to get the system to go into antilock mode. That will cycle the solenoids in the HCU. Then go back and bleed the system one more time. That should work.



Customer: replied 3 years ago.

the pedal fade that I described earlier, does that mean my Booster may be bad also?

No, but if you sill experience a pedal drop after replacing the HCU, then the master cylinder may be bypassing fluid internally.

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