Well, sounds familiar im sure, i have a very spungy brake pedal
87 camaro 4 disc, new 4 disc master cylinder and prop valve, stock L98 cam.
I tried everything.
New master cylinder, bench bled til no bubles.
Replaced front brake lines
Power bled the system through the master cylinder about 5 times, the brake booster whooshes pretty good when i press the pedal, which as i read is not an issue.

Car stops, the pedal does not max out, it does stop the car just not good enough and very squingee.

Any assistance/comments would be appreciated.

Niko

 

Anybody?

 

I have the SAME problem with my 88...HELP US!!!

 

i just installed rear disc on my 91 z28 this weekend from 84 camaro. i took the spring from inside the 84 prop valve and put it the 91 prop but kept the same valve inside from 91 prop. the 84 spring is shorter then the 91 spring, hoping it will get more brake fluid pressure to help the rear brakes, so far it has worked out good, so far.....

 

1st off- make sure you are producing at "least" 16 in/lbs of vacuum to the booster.

2nd, I would highly suggest switching to the 1LE (J65)proportion valve for pre '89 1/2 cars (GM # 14089496). This is a direct boltin valve for your car, no modification needed. You will gain much stronger rear brake proportion. The stock valve you have with the standard disc package (Non-1LE) is teribble- Ps-I have an '87 also and HAD the same problem.

 

Well, the rear is a 9 bolt Borg warner aluminum caliper disc from a 89 iroc and the prop valve matches it. How about getting a Wilwood adjustable valve that should work, right?

Niko

 

Inches of mercury (in/Hg), not pounds.

Sorry.

 

A wildwood proportioning valve is good! You can eliminate the terrible lockup at hard breaking in the rear. I think the 1LE prop. valve will work too - tho and might be the better bet as far as your buck is concerned.

 

You said you replaced the front brake lines but you didn't say with what. I put Earl's braided stainless lines on my car and the pedal feel difference is amazing. Rock solid, almost no movement.

 

Replaced with stockers. I know should have gone with the stainless stuff, but did not want to wait...