Hello, I have an 1986 Iroc with rear Discs on it. I noticed the car wasn't stoping that well so I checked to see if the back brakes were working and sure enough they aren't. The parking brake isn't working either. I first adjusted the parking brake to the specs givin in the Chiltons and still nothing. I then bought all new rear calipers and pads and bleeded the entire system and still NOTHING. The front brakes work just fine, but the back don't do anything at all, not even the parking brake. I know there is fluid going back there cause it was leaking when I took off the original calipers and when I bled the brakes fluid came out. I don't know how fast it should be squirting out when you bleed them with two people, but it didn't seem to be squirting, more of a steady stream. Any thoughts on what is going on??? Thanks for any help.

 

I dont know what is causing the problem.

But the problem seems to be a lack of line pressure in the rear system.

I would start by doing this. Unscrew the brake bleeders on the rear and have some one watch the open lines.

Pump the brakes a couple of times( yes air will get in but we have bigger problems) this will start the fluid moving. Leave the lines open and and get out add fluid to the master cylinder and wach the fluid run out. Leave the rear open and do the front.

I would run at least two changes of fluid through the master cylinder and let it drip out of all the wheel cylinders.

While this is going on crawl under the car and look for a crimped brake line.

Tighten the bleeders and bleed the break starting with the right rear and ending with the left front.

If you are getting good fluid flow and still have no brakes I would ckeck out the master cylinder.

Good Luck

 

https://www.thirdgen.org/techbb2/sho...hreadid=247419

 

Ok, I've been doing tons of research and search stuff and need help to finalize my conclusion.

My stock proportioning valve is Junk!
Take off the proportioning valve and throw it away.
Buy a Wilwood adjustable valve and install it on my rear brakes.

How does that sound?

Is it easier to gut the stock proportioning valve and leave it on there and then install the Wilwood adjustable one? I don't want my rears to lock at all, so the easy way of just gutting the stock valve is not an option.

Do I need to do anything else for my front brakes if I get rid of my stock proportioning valve?

Thanks for any answers!

 

I got the brakes to work finally! My problem was that I was bleeding the brakes way way wrong....don't ask. I got them all bled now and now everything works how it should. I don't know if the back brakes ever worked from the factory, but they sure do now. The parking brake works now too. I think the rebuilt calipers that I bought from O'Reilly's had the recall kit done on them because the parking brake works perfectly now. I'm glad I didn't try and install the proportioning valve because the back brakes work really really good, just thought I would share.

 

They'll work fine with or without the recall kit when they're first installed. You'll have to see if they keep working as the pads wear to know for sure.

 

Don't jinx it!

 

FYI about the recall kit: I've done it twice (two sets of calipers), the recall kit is only like $32 from GMPartsDirect.com I think is where I got it. I b'lieve the p/n is 18019028.

It is pretty easy. It takes some fiddling around because the screw-out parking brake adjuster likes to screw out while you're assembling it, meaning you have to take it back apart when you realize the pads won't fit in :-). But it is definitely doable for your average guy.

I would recommend doing it even if you bought rebuilt calipers, the one set I did it on were rebuilds from Pep Boys and they had NOT had the recall parts put in.

It'll be obvious when you go to do it, the recall pistons looked pretty different from the original pistons (black colored/anodized/something instead of shiny, IIRC).

I believe the spring and the piston are the two critical parts that are actually different, then they include all new seals washers etc just so you can do a complete rebuild.

 

I have checked with GM Parts Direct, and they do not list the p/n 18019028 as a recall kit. Is this p/n correct, or is there a different p/n ? I need to rebuild my rear 1LE PBR calipers, and this kit sounds like the way to go. Thanks, Ed.

 

GM calls it an actuator kit, not a recall kit. In any case, it's for cast iron Delco-Moraine calipers, not aluminum PBRs.

 

Thanks for the info. - I will go with standard rebuild kits for the 89-97 PBR Calipers. Ed.

 

Don't get confused..the recall kit is NOT for PBR calipers, only the older iron style.

Ed