Right front caliper not releasing
06-13-2009, 02:52 PM
#1
Heel & Toe
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Right front caliper not releasing
I have a 1988 C4 Corvette. My right front caliper is not releasing. I have removed the caliper and pistons to make sure everything is clean and working properly. I can not find a reason for the caliper not releasing. All of my other calipers are working fine. I was wondering if my ABS box might have something to do with it. If anyone has any ideas to help fix my problem, I'd appreciate it.
06-13-2009, 03:24 PM
#3
Heel & Toe
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Yes, I replaced it with a new hose. I am getting fluid to the caliper. The caliper pistons are extending, locking up the wheel, but not releasing. I checked everything back to the first section of steel line. I put everything back together and the brake is still not releasing. The only thing that is left to check is the rest of the steel line back to the ABS box and then from the ABS box to the master cylinder. Any ideas?
06-13-2009, 06:52 PM
#4
Drifting
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Yes, I replaced it with a new hose. I am getting fluid to the caliper. The caliper pistons are extending, locking up the wheel, but not releasing. I checked everything back to the first section of steel line. I put everything back together and the brake is still not releasing. The only thing that is left to check is the rest of the steel line back to the ABS box and then from the ABS box to the master cylinder. Any ideas?
Further presume, while the caliper is not releasing the rotor, if the caliper bleeder is openned, the caliper DOES release the rotor.
So it is likely the ABS unit.
However, it might not need to be replaced... it might just be a valve inside which is out-of-position.
Sometimes the order of bleeding the wheels, if done incorrectly, can cause the internal valves to become mis-positioned, and the problem you are encountering.
Suggest reviewing your FSM or someone's with the same year and do/repeat the bleeding sequence exactly per the FSM.
Alternatively or thereafter, someone with a Tech-1 (dealer/friend) should be able to run the ABS unit through its diagnostics/reset procedure -- which might correct it.
If neither of above solve the problem, ouch -- maybe it is the ABS unit.
06-17-2009, 11:41 PM
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Pro
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06-18-2009, 12:18 PM
#7
Le Mans Master
I have not seen this problem for a while on the Forum but a couple years back there was rash of calipers that were not releasing where the problem was the ABS unit. For some reason the ABS units of that vintage seem to develop this problem.
