I swapped in a 2000 rear end with the 12" discs, I got a porportionary valve from a disc/disc iroc and the rear brakes dont even have enough pressure to stop the wheels at an idle. I thought maybe I got a bad valve so I got another porportionary. I bled the system the brake light went out and same situation. Does anyone have any idea what the problem could be? Thanks.

James

 

Which valve did you swap in? The standard disc/disc valve (82-88 with Delco-Moraine iron calipers and 10.5" rotors) or the disc/disc 1LE valve?

JamesC

 

sounds like he used a regular Iroc proportioning valve

 

I was told it was from an 89 Formula with PBR disc's, is there anyway to tell by the numbers stamped on the side? Thanks for the quick responses.

 

A standard metric valve has the same threads as an early 89 1LE, so the former would fit. There's no way to visually distinguish a standard valve from a 1LE. If the valve is truly from an 89 with PBR's, you should have the correct valve.

JamesC

 

You just need to change the spring in the front like 89TransAmGTA said.

 

So is there anything else that could be causing my problem? My front brakes work fine, but like I said I lifted the rear end up and with the pedal to the floor it couldnt stop the wheels idleing in gear, theres not enough pressure to hold to pad to the rotor and it squeeks horribly and is very annoying. I might just to have to start hunting for a disc/disc car around here and pull it myself. Is it 90 when the threads changed?

 

How do I get the spring I need?

 

Update: I tried removing the spring and plunger and using a plug which correct me if I'm wrong should give almost 100% to the rears? Well the brakes work a little better, I can get them to hold the coverter to 2000rpms but there still isnt enough pressure to keep the pads against the rotors and I still get the annoying squeek while driving. What do I do from here?