I just finished my rear disc brake conversion, but my question is what going on when my calipers seem so tight that the wheels will not turn unless I hit the gas. I bled the brakes and fluid is making it to the back although I'm not using a proportioning valve, it seems like I need to push da pedal almost to the floor to get it to stoo, but what do I need to get the wheels to move freely, it sounds like there is friction some where. I thought I had rear end issues. My calipers and brackets came off a 2000 Jimmy which fits fine. I'm working on a 81 Cutlass. This is while the car is on stands. Video was too large to load so you guys can see. No thread was if help!!
Rear disc brake conversion
- Thread starter Mean_n
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You'll need a disc/disc or adjustable proportioning valve, the original proportioning valve is disc/drum and designed to keep some pressure in the rear brake line
The stock proportioning valve on my grand prix is on the driver side frame rail just under the firewall. You plumb in a new proportioning valve basically where ever you want, most guys place them just under the master but I remember one of the other forum members saying they had installed their adjustable prop. valve just under the driver side door for easy adjustment.
Yes you will be replacing the original disc/drum proportioning valve with the new adjustable or disc/disc one. From the info in your original post I believe this should fix your problem.
I don't think there is any residual valve in the proportioning valve. Guys in here have the rear disk set up and are using the original master brake and proportioning valve. Is your caliper centered on the rotor?
No proportioning/combination valve? Probably not the greatest of ideas. You need to balance the load to keep the rears from locking up first.
How old is the rear brake hose? If it's original to the car, it may be old enough to break down inside, which then acts like a check valve keeping pressure from releasing. Or there may be a kink in the line which could mimic that too. Just throwing spaghetti on the wall.
How old is the rear brake hose? If it's original to the car, it may be old enough to break down inside, which then acts like a check valve keeping pressure from releasing. Or there may be a kink in the line which could mimic that too. Just throwing spaghetti on the wall.
I read somewhere the residual valve was in the factory master. I put blazer rear disks and ls1 front disks in my GP and it was terrible. I swapped to a disk/disk prop valve and it was worse. I put the factory disk drum prop valve back on and a 88 Caprice master and it was way better.
Your problem sounds like the calipers aren't releasing. Can you lift the car and see if it's the front or rear that's holding it up?
Your problem sounds like the calipers aren't releasing. Can you lift the car and see if it's the front or rear that's holding it up?
they use to put a residual valve in the master but they stopped long ago. The master sits high enough to provide the pressure. If you have a floor mounted master then you do need to put in a 2lb for disk and 10 lbs for a drum brake
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