Mechanics

LLOW BRAKE PEDAL

1996 Geo Prizm

Brakes problem
1996 Geo Prizm 4 cyl Front Wheel Drive Automatic 122, 00 miles

Hi
My son owns a 96 Geo Prism. When we first purchased the car, the brakes seemed fine. That was over a year ago. I drove it a few days ago and was surprised to find the brake pedal went very low to the floor before beginning to stop! (At least halfway or more) There doesn't seem to be air in the system, but I bled it to be sure. The brakes aren't spongy at all.
I checked the front brakes and they were fine, I actually expected them to be in worse shape since we haven't ever replaced them since we bought the car. The rears looked ok, as they were replaced just before I bought the car. I did adjust them though, up to the drum then backed off a tad. This didn't help with the low pedal at all.
The master cylinder is always full, I never have to add fluid.
While the car was out of gear, I jacked the front of the car up and spun both of the tires, then my son applied the brakes. Both front tires stopped. I was thinking that maybe the front brakes weren't working properly, but they appear to be. This may not be a very good test though. I hate to just buy parts without some thoughts on what the problem might be.
Any ideas would be greatly appreciated as my next step of diagnosing this problem.
Thanks again, Mark
Avatar
Kywingnut
April 20, 2008.




Replace the power booster (behind petal). I do not think you will find one in a junk yard but if you do it should work.

Tiny
Kevin12881
Apr 20, 2008.
Kevin
Thanks for your quick response to my question.
I for got to mention that I had checked the brake booster by pumping the brake pedal with the engine off until I had bled off all the vacuum from the booster. Then, I held the pedal down and started the engine. I felt the pedal depress slightly as vacuum entered the booster. I thought this test might indicate that my booster is ok. What are your thoughts? Is this a good booster check, or do you think I hould still change out the unit?
Thanks again, Mark
AD

Tiny
Kywingnut
Apr 20, 2008.

AD