Just got the car fired up this weekend and got the brakes bled.

I swapped in a PBR setup out of a 91Z into my 88, so new brake lines all the way around, rotors, pads etc...

The drivers side Caliper is sticking pretty bad, passenger side is fine. I can barely move the rear wheels in neutral with the brakes disengaged, so they are releasing some, just not completely. Should I just pump them a bunch of times and see if it frees up? The car is still kinda tore down, even though the drivetrain is in place now, so I cant really drive it to see.

Any thoughts on what could be causing it to drag, or what I can do to help remedy the situation?

 

If your 88 was an original four wheel disc car with the iron calipers, I've heard that particular proportioning valve doesn't work properly with the pbr brakes. You'll probably need to get a proportioning valve from an 89 model. You don't want to go much newer than 89 or 90 since gm changed the thread pitch on the brake lines sometime after that. I'm running pbr rears with an original 89 drum brake proportioning valve, and it works just fine. The older saginaw iron calipers required a lot different fluid volume than the pbr calipers do, hence your problem.

 

My car was a Drum rear. I still have the Prop valve from the Drum's in there now. I dont think that is the issue at the moment, because the pass side caliper is releasing, the drivers side is not.

 

Lube the slider pins? Another thought: Did you shim the backing plate so that the carrier is centered over the rotor?

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

JamesC

 

The rear and the brakes are all original (new rotors) so I dunno if I need any shims.

I did the reading on the free travel. That looks like it could be something. I did some looking at the ebrake and it looks like it might still be catching.

Gonna have to play around with it some to find out.

 

If you didn't rebuild the calipers, chances are the free travel is Ok (unless problems already existed). Anyway, keep the shim idea in mind.

JamesC

 

Yeah, I didnt rebuild them. I dont know how long they sat before I got the rear. They sat about 8 months since I got em till I pumped the brakes the other day.

When we were putting them together, that caliper didnt want to release enough to go on, we had to futz around with it to get it to release enough...

 

I would check the slider pins as mentioned, it has happened to me before, turned out the slider pin was not only dirty preventing the free movement, it was also bent a little causing the caliper to get stuck. I wasn't aware of this until too late, unfortunately the caliper piston siezed in the outward position. So I had to either get a rebuilt one or rebuild one myself. With the "new" good working caliper I cleaned all the pins and re-greased them when re-installing. I would just disassemble the suspect caliper, remove it from the car, check/clean/grease the pins, make sure the piston isn't siezed. If all checks out good then try watch how much fluid comes out of the line when you pump the brakes, could be a stuck line only to that one side caliper or something. The rear brake lines has a "T" fitting usually right above the diff, possible one side is not getting as much fluid as it should.

 

Yeah, the slider pins are definitely a good thing to check as well. The first time I checked mine, the lower ones had nothing but red dust(rust) in the bores.

 

does anyone have any pictures of what I need to be looking at as far as lubing the sliders? and what type of lube should be used on them?

I am far from a pro at this, so go easy on me

I took a look at the rotor and it looks like the top part of the pad is catching, where the bottom (closest to the inner part of hub) is not doing anything.

My guess is I need to clean it up as you all are describing, but I need some guidance as I dont have a Maintenance book for the 91, only the 88.

Thanks in advance guys.

 

or am I better off just getting a replacement caliper?

Id prefer to not spend the $100 for a new one if I dont have to, but you know how that is...

 

Check the following link (the slider pins have the rubber weather boots). I'd spray the bores with brake cleaner to eliminate the accumulated crude, if any, then lube the pins with Sil-Glyde (Napa) or any synthetic brake caliper grease.

https://www.thirdgen.org/forums/atta...s-89-lline.jpg

JamesC

 

Well, I got it working.

The slider pins werent too bad, but the grease was kinda dry. I cleaned them all up and relubed them. Then I took a big C-Clamp and pressed the Piston all the way back in. Pushed it back out with the pedal, then Pressed it back in with the C-Clamp again. Finished cleaning everything back up, and put it all back together and all is well.

It seems much happier now

Its amazing how easy it was to take it all apart and put it back together again.