I have a 87 GTA with the 4 wheel disc rear iron calipers. The problem is I installed the recall kit and at the same time I installed earls ss brake lines. I also had the rotors turned. They are bled correctly becausethe pedal IS NOT spongy, it is firm. As of right now they are still not working. I have to pump the brake pedal 2 times real fast and I then can feel the rears working. The rotors are even starting to rust. Do I need to do something with the prop valve or is there something else I need to look at? It also has a new master cylinder on it 10000 miles ago.

 

I had to add three machinists' washers to the proportioning valve on my '89 Gta to get them to work. There is a lot of arguements about rear discs. I think the best way to fix them is to pull the plug and spring on out of the pv and put an allen plug in and then add an aftermarket control valve...my washers work good though. There are several other posts about this. Easy to find.

later, justin...

 

Shagwell, where exactly did you put the washers in the p/v, between the spring and plunger? and what size and thickness did you use?

 

Between the spring and the plug(if I remember correctly), and I used yellow(10-12) electrical connector eyelets. I cut the eyelets off the ends, and put them in. I experimented on an old runway, tryin from 1-4 washers. With my car, 3 washers made the rears lock just after the fronts lock. Made a huge difference in my stopping power. Some people say this may turn your light on in the dash, but it didn't w/ mine...

later, justin...

 

For your year car use the 1LE (j65) combo(proportioning) valve- GM part # 14089496- This is the 1LE performance package prop valve for the pre '89 cars with 4 wheel discs. The thread pitches willl all match what you have, bolts right in.

p.s. I have an '87 Camaro that had disc/drum and had the same problem. Its now Disc/disc with the 1le valve on Non-performance package calipers and stops fantastic with that valve change. I'm the guy that posted the mod to the drum proportioning valve as a cheap fix(Afrikin)- it works- but changing to the 1LE valve is better.

 

AGood2.8,

I have an 87GTA with iron calipers in the rear, if I were to install this 1LE proportioning valve GM part number 14089496, (~$50) that you make reference to, would that actually make my rears work ?

Thanks

 

Yes, beautifully. I also have iron calipers front and rear. The stock combo valve was crap- rears did not work at all until I modified the valve- eventually the front started to go to heii so I switched to the 1LE combo valve and wow- perfect balance and stopping power. Here's a pic of my front caliper- 1LE valve works great with non-1LE brakes

 

rear binder-Iron also. Note: I run drilled rotors in the rear for better initial bite (rears bite sooner than the fronts with soft pedal- better for setting chassis attitude- no pad float in the rear/ but when pressed harder, the fronts come on stronger)

 

AGood2.8,

Just the answer I was looking for !!! Thank so much for the info and pics. Those rotors look really sweet. Nice looking set up!!

 

I will try the 1LE valve and let you guys know the results