1998 Chevy Prizm Brakes failed but now are OK

SGF

MEMBER
1998 CHEVROLET PRIZM
4 CYL
2WD
AUTOMATIC
124,000 MILES

My wife drove my car and after a few miles on the hwy the brake pedal went all the way to the floor. Pulled off, and they were OK for a few blocks 'til the pedal went to the floor and she hit someone at very low speed. I checked and there doesn't seem to be any fluid loss or leaks at master cyl. Pedal seems ok, stays solid, goes down when you start the car. Doesn't appear to be spongy. The fluid is a little dirty so I will bleed for starters. I can drive the car and nothing seems wrong with the brakes. Any ideas on what could have caused this brake failure? I have never heard of this 'temporary' failure.

1 Reply

ZACKMAN

MECHANIC
4,202 POSTS

Replace or overhaul your master cylinder. One of the rubber parts has developed intermittent air leak causing the master cylinder loses its vacuum and the pedal goes down to the floor. If you pump the pedal several times, the master cylinder creates some vacuum and the brake works again until the leak appears and m/c loses the vacuum and the process repeats itself.