I've got an 86 IROC with the J65 rpo (crap 4 wheel disc) and the rear brakes really suck. I've just rebuilt the calipers and replaced the lines so it's all new. They still suck. I was wondering if the 1LE prop valve would fix this? If so, what part number do I need, and where do I go about getting it? I searched and couldn't find a straight answer so I figured I'd ask.

I'd like to know too...
Anybody?

No.

What exactly is the problem?

You are aware that there was a recall for sticks equipped with those brakes, right?

Many of the members have replaced the original Delco Moraine's with PBRs.

It's not the brakes. You can put on brand new brakes but the prop valve has too much bias. I've got an original auto anyway. I just fixed the problem by taking out the spring and piston and welding the hole in the cap closed. Now the brakes actually work. And don't try to tell me that it was the brakes or the lines or master cylinded. I replaced all those and still had the problem.

I didn't realize I had a problem until I had the car on stands and started it. As soon as I put into gear the wheels began turning like they should. I hit the brakes and they would only stop when I put as much pressure as possible on the pedal. Even then they would inch forward every once in a while. I found out it was the prop valve from an old post of people having the same problem. As soon as I welded the hole in the cap and removed the piston and spring they would they stopped just like I wanted. The car stops on a dime now and contrary to what some people think, the rear wheels do not lock before the fronts.

I'm not following you. Your first post says the brakes suck and then your most recent post says it's not the brakes.

Keep in mind that you definitely do NOT want the rear brakes to lock up first. That is a recipe for a disaster.

The fact that you have an auto doesn't make a difference when it comes to those Delco Moraine brakes and the recall. Cars with an auto weren't part of the recall, but they had the same problem. The problem you describe sounds like the one with the Delco-Moraine brakes. My problem with them was even worse. The rear brakes did not work at all.

What some people on this board have done is switch to PBRs in the rear. I've got all the parts, I just haven't done the swap.

Do a search for posts by ebmiller88 on this subject.

The the part # of the 1LE valve in the following link, which also provides all the info for a PBR swap:

https://www.thirdgen.org/forums/faq-...iscs-89-a.html

JamesC

I thought it was the brakes and got the recall kit and did the rebuild. It didn't change anything. Then I replaced the lines from the prop valve all the way back, including the 2 rubber lines in the rear. Then I replaced the master cylinder. When none of that worked I decided to do the prop valve mod which I found in another post. It's the only thing that worked.

I didn't say my rear brakes locked up first either. I know exactly what happens when the rears lock. Mine don't. Besides, I know how to not lock up brakes. I'm not some dumb *** with his first car. Maybe it's done it on other vehicles but not mine.