Heres the deal, I've been having the same problem with my brakes for about a year and have tried almost everything to get them working properly again. My problem is that I can drive down the road and slam my pedal to the floor and the brakes wont even come close to locking up. In fact, if i slam the pedal at idle the car will take a good 2 feet to stop. Things ive tried to fix this problem: brake booster, rotors, pads, flex lines, calipers. The only thing that I didn't replace would be my master cylender. Any help?

 

I have a 1992 also, did a rear disc swap. Same problem as you, still working on fixing it. Eveything but the booster has been replaced. Sorry I could not help, it seems like a common problem with these cars.

 

If the master cylinder was out I believe the pedal would be very mushy.

 

Sounds like the only two things left are the master and prop valve.

greg320:

Did you swap to a disk/disk prop valve when you put the rear disks in? I just did the LS1 rear brake swap onto a 3.73/eaton posi rear I bought, and for grins I tried the brakes with the disk/drum prop valve. No matter how hard I pushed on the brakes I couldn't stop the rears from turning with the car on jack stands. Wouldn't even push on the pads enough to take the surface rust off them that had accumulated after having the rotors turned. Swapped in the disk/disk valve and they work like gang busters now. Nice shiny rear rotors and very touchy brake pedal.

 

Yes, I did swap to a disc/disc valve. Today I eliminated that , I took the prop valve out and now running full power to the front all the time and an adjustable prop valve on the back. Still no help. Tommorow I am putting in a new booster, it is about the only thing left. Will let you guys know..

 

when i replaced my rear with a 4th gen 3.42 posi w/disc brakes, i left my prop. valve untouched. I still have the disc/drum prop valve installed, do you think this is my problem. Had numerous people tell me that the prop. valve did NOT need to be changed.

 

There is another thread about drum to disk swap and both FUNIROC and I posted about the prop valve after a rear disk swap.

I did a 3.73/eaton/LS1 rear disk swap and just for grins I bleed the rear brakes and tried them to see what they would do with the disk/drum prop valve. With the car on stands the rear brakes wouldn't even lug the motor down, much less stop the rear from rotating. I swapped in the disk/disk valve and what a difference. Actually killed the motor with a light touch on the pedal when I tried them, where with the disk/drum valve the pads wouldn't even rub the surface rust off that had accumulated on the rotors after having then turned.

I've read that the newer cars have the same prop valve and there is no need to change it out. To me that doesn't make sense. A drum brake will operate at a different pressure than a disk will, so with a difference in pressure one would think the prop valves would be different. If your having problems and can't solve it, you might try changing the prop valve out and see if it works. Sounds like you don't have much to lose at this point.

 

i totally agree with you, where can I get a disc/disc prop valve? Links would be nice

 

I don't have any links. I remember reading somewhere the one for my car was discontinued. Luckily I found a disk/disk car in a junk yard and got one off it.

As I recall, Ed Miller was selling some new disk/disk prop valves awhile back. Might try to contact him. I'll also keep an eye open for another disk/disk car to grab another valve off of. They seem to be in demand lately.

 

alright thanks, any one else help me out here and tell me where i can get a disk/disk prov valve other than a junk yard? will a 4th gen prop valve work?