rock hard brake pedal

[dylan]

i was driving down the road and my brake pedal went hard as a rock and wouldnt move.. i had t stomp the brake pedal with both feet to get it freed up. any suggestions as to what could be my problem.. its a 1994 s10.. 4wd 4.3 motor

Topic

[Joeseph Mama]

since your problem involves the brake pedal and not an individual brake, I would work from the brake booster back towards the pedal to isolate the cause of the problem.

i would first check the brake booster. it has a check-valve that is prone to failure. additionally, you should check for vacuum leaks around the brake booster. Lastly, you should take a vacuum measurement at the booster; it should be around -18mg” at engine idle.

if you found the problem, then stop here. if not, examine the master cylinder for some type of unusual failure.

also, look up around the brake pedal itself for obvious problems or debris limiting pedal travel.

[dylan]

Thanks for the information.. i replaced the master cylinder and my brakes worked fine for about a week.. it turned out to be the hydraulic motor in my abs system was freezing up and not letting me apply my brakes

[EricTheCarGuy]

That’s a new one on me. Thanks for that update. Sounds expensive. Was it?

[Stephen Bowen]

Eric, Had the same part fail on an astro van I used to drive for work. Dealership tried (and failed) to bill the fleet company for about 650 bucks for a rebuilt unit plus diag & labor. It was just at the end of the warranty period. So that’s not a cheap one from a dealership, at least not several years ago. Other rebuilding companies probably got on board to offer cheaper solutions.

[Author]

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