asherwood

I know that this is not a FC related question, but I need to help my dad get his '92 Grand-Am ABS brakes working!

Intermittently as the car comes to a stop, just before forward motion halts, the car lurches forward as if the brakes have failed (very scarey ), without enough room between you and the next car it's an accident waiting to happen.

The ABS module has been replaced and the rest of the system checked by the GM mechanics, but the problem remains. They just don't know what to change next. You know what it's like, they road test it and pronounce that all is well.

Any information directly relating to this kind of failure as well as links to sites with additional info would be much appreciated

cbrock

iTrader: (1)

sounds like one of the valves inside the abs unit is sticking. Although your brakes should work just like regular non abs brakes when you are not in an abs event. Question? Does the pedel go to the floor, or does it just become rock hard at a certain spot. However, my best guess is on the valve itself. On it is a rubber ring that is suppose to be flexable in one direction. Perhaps one of these rings has failed and is allowing pressure to escape. Try getting the entire unit out of junk car. Also, if they pulled the unit all the way apart there is a good chance that the system is dirty now. Small particles can really F these units up. Lastly, do you happen to know who makes the unit? It should say on the black cover. Bosch, Kelsy, TRW...etc etc. When I go into work tomorrow I'll talk to some of the product guys and see what they think.

asherwood

I'll check about the pedal. Is the ABS unit and control unit in the same box or can they be replaced seperatly?

I'll also have to confirm the name on the outside.

What would make the failure intermittent?, almost sounds like an electrical connection problem.