jpearcy1

iTrader: (1)

First I want to say rear pad install on our cars is a nightmare.

To to my question though. With the rear end on jack stands and wheels off, will the rear calipers completely stop the rear from spinning if in drive? I noticed mine will continue to spin slowly with brakes applied. I have new pads and new calipers on the rear as of now.

Is it possible the proportioning valve or master cyclinder could be bad?

Any info would be great thanks

Drew

iTrader: (58)

It's more likely the rear circuit is blocked someplace. People barely change their oil on a regular basis, much less flush their brake fluid. Over time the fluid absorbs water, the water corrodes, the fluid turns to mud, etc. The rubber hoses break down, the steel end fittings rust closed, etc... In other words, start by bleeding the rear brakes until the fluid starts to come out clean. If they won't bleed, start looking at the hoses.

jpearcy1

iTrader: (1)

I have bleed the system a lot. Before I even put pads or calipers on. When I first started the fluid was the color of coke. Now I have clean brake fluid every pump. I didn't just throw calipers at it hoping to fix problem either. When putting pads on I had one caliper seize and decided to replace both.

naf

iTrader: (7)

the 87 should have the cast iron delco moraine calipers.

the calipers likely need to be manually adjusted to the new pads and rotors. the self adjustment works through application of the parking brake but is a troublesome and finicky beast.

jpearcy1

iTrader: (1)

Do you have any more information on adjusting them? I have never read anything on that.

Drew

iTrader: (58)

But did you replace the rubber hoses? Did they bleed normally? I'm not generally one to *****-nilly throw parts at a problem, but with the age of these cars I'm feeling more and more that the OE brake hoses are probably due to be replaced. The fronts are pretty obvious about problems, but the rears do so little of the braking anyway, it'd be hard to tell if they were blocked. By all means do the adjustments first, but consider the possibility.

jpearcy1

iTrader: (1)

I did not replace any of the brake hoses yet. I plan to eventually but as of now both calipers bleed easily.

Also did a test drive today with new pads (front and rear) braking is much much better than before but still can not lock up all 4 tires.

Drew

iTrader: (58)

Yeah, probably won't ever lock up the rears on a thirdgen with the stock brake bias. Even the 10.5" fronts are seldom if ever going to grab hard enough to overcome the traction of a good 245/50R16. Seems like your expectations might be a bit out of line.

jpearcy1

iTrader: (1)

More along the lines of I didn't know. I assumed that it would be able to. I guess for now I will live with the stock brakes.

someone972

iTrader: (2)

After switching from stock drum to 4th gen rear with PBR brakes, I had the same problem. Unable to stop the rear wheels up on jack stands. I ended up putting a proportioning valve inline with the rears and gutting the prop valve portion of the stock combo valve. Turns out I have it set at full pressure and still can't lock the rear brakes, but they easily stop the wheels on jack stands now. At least if I upgrade in the future the adjustable prop valve is there.

1985_IROC

If they are four wheel disk brakes, I just replaced my rear calipers and learned a lot. You should not adjust the parking brake cable by tightening it. You have to loosen it so that the rear caliper arms come all the way out - this allows for the caliper piston to pop out a notch closer to the disc. This is how they self adjust. If you over tighten the parking brake cabling, then the parking brake arm on the caliper will never extend far enough to self adjust.

Try taking the parking cable off the arm, pull the arm all the way back and see if the piston comes out. If not you may have bad caliper...

jpearcy1

iTrader: (1)

I had one bad caliper so I replaced both calipers. I did not adjust my parking brake cable also. I couldn't adjust it due to being so rusted.

1985_IROC

Great, then you need to manually adjust the rear calipers with the parking brake arm so that the piston comes out closer to the disks. If you pull the arm back it should come out to the next self locking position point. Here are some helpful docs that I found that might help explain how to adjust them:

http://www.classicperform.com/Instru...structions.pdf

http://my.cardone.com/techdocs/PT%2018-0001.pdf

jpearcy1

iTrader: (1)

Awesome I will have to give this a try soon.