I have an extremely soft brake pedal. 1989 C4. At startup I can hear the anti-lock kick in. I have bleed the brakes with a pump with the correct rotation from wheel to wheel. I'm pretty sure I got all of the air out of the system. I pumped until I got new fluid out of each wheel. The brakes are just as spongy as they were. What else could be the problem. The brakes work, I just have to put the pedal near the floor for it to work. Any help would be appreciated.

 

Well I really don't have an answer for you but Welcome to the site. There are a lot of very knowledgeable folks here and I'm sure someone will give you the answer you seek. My first thought was the booster but that's just a guess. Don't forget the wave. Cheers

 

Could be the master cylinder or the ABS valve. Might have to use some vise grips to pinch off the rubber brake lines to determine where the problem lies (rear hoses 1st, then front ones). My money is on the Master cylinder and hope it is not the the ABS valve, because they are hard to find.

 

I have learned from my experience to always double and triple check everything before buying expensive parts. I would have someone to pump up and hold the brakes for me while I bled them out. I am not doubting your work, but I have done this before and told someone I knew I had all the air out, but lo and behold when I rechecked, there was still air. I would do this two or three times to make sure there is no air before moving on to something else. I also learned this about a battery drainproblem. Turned out to be a bad battery, just as the members on this site advised.I didn't think it was bad. I hope it is only air. and it takes care of your problem.

 

I would double and triple check to make absolutely there is now air in the system before checking something else. I doesn't take much to make a soft pedal. Brake fluid is cheap compared to parts. Be sure to keep the resevoir full of fluid while bleeding to prevent more air being put into the system.

 

Hi bigwop... soft pedal is usually air in the system or master cylinder. A power bleeder is the best way to bleed the air but it is a tool that can only be used for brakes. I have had very good luck using a hand vacuum pump to bleed brakes and to flush the brake system. They can be purchased at auto zone or similar stores. I think mine is called Mighty Vac. They can also be used for testing vacuum leaks and such. I think the noise you here at start up is a normal noise for a 88-93 corvette abs system doing a self check of the system at start and usually continues for a few hundred feet. You will probably here this same noise applying the brakes firmly at 55 slowing down for a light and you will get a quick abs active light. It surprises me nobody everposts about these noises because they are very annoying. I would like to here feed back on these noises for abs brakes on the 88-93 Corvettes.How about it guys what kind of noises do you have?? I think you should bleed more and if that doesn't do it start looking at the master cylinder.
Bigwop good luck with the brakes (let us know)
Ric W.

 

how about some history,when did this start ? has anyone worked on brakes,tires etc ? has the master run dry ?its been like this when ya bought it new ? can you pump it up and get a high pedal ? how are the pads ? are the caliphers free ?

 

I bought the car about 6 months ago. The brakes have been this way the whole time. I can get the pedal a little higher with pumping. I did run the master dry while bleeding the rear brakes, but my wife finally showed up to help me and I'm pretty sure I got all of the air out of the system. I bleed from each wheel until I got new fluid. The brakes work, the car stops, but I don't like the low pedal.

 

Always when you bleed, start at the furtherest point and come to the nearest point, that is RR, LR, LF, RF. If you are by yourself, you can gravity bleed the system by cracking all bleeders and then keep the master cylinder filled. Usually gravity bleeding takes about 30 minutes.

 

Wow wondered about the abs noise!