I've a 1987 T/A GTA factory 4 wheel Disc. I have very little rear brake pressure and it's been like this since I first bought the car in 1997. I've only put 60'000 Km's on since then. This can't be normal. My rear disc and pads were installed 10 years ago and theres no wear on the pads at all. I've changed the pads, the rotors, and the master cylinder, as well as calipers. If my cars is stopped on wet leaves or a little mud or ice the rear wheels turn. I have to put it in neutral. When I bled them the brake fluid just spilled out of the line, there was very little pressure as compared to the front. Pulling the e-brake does nothing either. I'd like to finally get to the bottom of this because this can't be right. Can it be a bad proportioning valve?

 

Sounds like you had the same problem I had.

https://www.thirdgen.org/forums/brak...rakes-j65.html

 

Many users have found the pre-89 rear discs to have very low pressure stock. Some users replaced the prop valve with a later year part and have had success. I gutted the stock prop valve and installed a wilwood adjustable valve and dialed in the rear brakes to my liking. Braking is much improved.

The solution for the e-brake is to install the GM recall kit which replaces the pistons in the calipers.

 

Where does one get this recall kit? I'm sure GM is not going to honour a recall now.