for the last month or so i have suspected that my back breaks are no more. so yesterday i took the car over to a friends with a lift. we lifted her off the ground, put her in gear, and sure enough the rear was still going with the brakes fully pressed.

its an 89, rear disc setup.

also, it makes no difference wither the foot or e-brake is used, same result!

what is the first things i should check?

 

try adjusting your e-brake and if that dosent do the trick do a search as there is lots of info on poor rear brakes on this site.
pete

 

When's the last time the rear brake lines were replaced? Try bleeding the hell out of them, see if you have a blockage somewhere.


Ed

 

I had the same problem with mine. Mine has the moraine calipers not the PBR's, but I tried everything. Rebuilt calipers blew out hard lines, replaced both rubber lines, adjustments etc. I ended up using a brake pressure gauge, and found really low pressure. So I ditched the stock combination valve and put in an adjustable. Brakes are 100% better.

 

Funny, I just "found" the same problem on my 86 IROC today. E-brake wouldn't work, jacked it up, started it up, put it in gear and hit the brakes and the wheels kept going. It has new pads and calipers from last summer. No brake light when stepping on the brake pedal even when hitting it hard out on the highway. The tip about the proportioning valve (?) might be a good one. The shop manual lists a malfunctioning metering valve as one of the causes of poor rear brakes. I guess I'll take a trip to Advance Auto or Auto Zone tomorrow and see if it works for me.

 

I'll address the PBRs only here as that's what the poster needs help with:

Take a look at these threads I've posted in. What a lot of people don't know is that there are 3 adjustments that need to be done to PBR calipers in order for the e-brake to engage right. First off, make sure they are fully bled (obvious);

Secondly, you nay need to crawl under the car and mess with the adjustment on the lever in the trans tunnel. Third, there's a SMALL Allen screw located on the caliper itself (and it's usually frozen) that controls the position of the pressure plate. If this isn't properly adjusted, the plate won't fully engage the pad/rotor and may bind a bit. Here's that topic in detail:


https://www.thirdgen.org/techbb2/sho...ghlight=ebrake

https://www.thirdgen.org/techbb2/sho...djusting+brake

Ed

 

I wouldn't worry about it... Poor man's line lock!!

And thanks for those links, ed... I'll be using them when I get my rears fixed, too.