Rear brake locked up
Thread Starter
Instructor
Joined: Mar 2014
Posts: 104
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From: Frankfort IL
Rear brake locked up
Hey all, the right rear brake on my 1981 locked up on me back in September. I had it towed to the house ad its been sitting in the garage since then. I finally have some time to get into it and when I removed the brake pads and attempted to press the pistons in I got some fluid leak from the outboard rear piston when I attempted to depress the inboard pistons. I have a few questions:
1) If the pistons were pressed in individually instead of as a set (inboard + outboard) can this cause the fluid to leak from the opposite side being pressed?
2) I also noticed the bottom bolt that mounts the calipers to the frame was missing allowing the calipers to shift slightly up and down. Could this have caused the brakes to lockup?
I noticed once it locked up I couldn't drive it forward anymore. However after it locked I could reverse to free up the brakes and apply them without them locking up again until I drove forward. Should I just replace the mounting bolt, reassemble and give it a nice easy test drive? Thanks for the help!
1) If the pistons were pressed in individually instead of as a set (inboard + outboard) can this cause the fluid to leak from the opposite side being pressed?
2) I also noticed the bottom bolt that mounts the calipers to the frame was missing allowing the calipers to shift slightly up and down. Could this have caused the brakes to lockup?
I noticed once it locked up I couldn't drive it forward anymore. However after it locked I could reverse to free up the brakes and apply them without them locking up again until I drove forward. Should I just replace the mounting bolt, reassemble and give it a nice easy test drive? Thanks for the help!
Le Mans Master
Joined: Sep 2003
Posts: 8,812
Likes: 2,029
From: eastern NC
Hey all, the right rear brake on my 1981 locked up on me back in September. I had it towed to the house ad its been sitting in the garage since then. I finally have some time to get into it and when I removed the brake pads and attempted to press the pistons in I got some fluid leak from the outboard rear piston when I attempted to depress the inboard pistons. I have a few questions:
1) If the pistons were pressed in individually instead of as a set (inboard + outboard) can this cause the fluid to leak from the opposite side being pressed?
2) I also noticed the bottom bolt that mounts the calipers to the frame was missing allowing the calipers to shift slightly up and down. Could this have caused the brakes to lockup?
I noticed once it locked up I couldn't drive it forward anymore. However after it locked I could reverse to free up the brakes and apply them without them locking up again until I drove forward. Should I just replace the mounting bolt, reassemble and give it a nice easy test drive? Thanks for the help!
1) If the pistons were pressed in individually instead of as a set (inboard + outboard) can this cause the fluid to leak from the opposite side being pressed?
2) I also noticed the bottom bolt that mounts the calipers to the frame was missing allowing the calipers to shift slightly up and down. Could this have caused the brakes to lockup?
I noticed once it locked up I couldn't drive it forward anymore. However after it locked I could reverse to free up the brakes and apply them without them locking up again until I drove forward. Should I just replace the mounting bolt, reassemble and give it a nice easy test drive? Thanks for the help!
If this is the case, just inserting a new bolt in the caliper will correct the problem.
Of course you will still have to address the leaking caliper issue you now have. If you remove one of the brake pads and then attempt to depress the pistons on the opposite side, you can effectively unseat the piston(s) on the first side (since there is no pad to hold them in place). At the very least, you will need to re-seat the pistons that are now leaking.
Good luck and let us know what you find... GUSTO
Thread Starter
Instructor
Joined: Mar 2014
Posts: 104
Likes: 0
From: Frankfort IL
Check the inside of your wheel and see if there is evidence of the caliper having rubbed on the inside of the rim. I have seen a missing bolt before allow the caliper to rotate when the brakes are applied and wedge between the wheel and the caliper, effectively locking the wheel. When backing up the caliper is freed and it will now rotate.
If this is the case, just inserting a new bolt in the caliper will correct the problem.
Of course you will still have to address the leaking caliper issue you now have. If you remove one of the brake pads and then attempt to depress the pistons on the opposite side, you can effectively unseat the piston(s) on the first side (since there is no pad to hold them in place). At the very least, you will need to re-seat the pistons that are now leaking.
Good luck and let us know what you find... GUSTO
If this is the case, just inserting a new bolt in the caliper will correct the problem.
Of course you will still have to address the leaking caliper issue you now have. If you remove one of the brake pads and then attempt to depress the pistons on the opposite side, you can effectively unseat the piston(s) on the first side (since there is no pad to hold them in place). At the very least, you will need to re-seat the pistons that are now leaking.
Good luck and let us know what you find... GUSTO
Le Mans Master
Joined: Sep 2003
Posts: 8,812
Likes: 2,029
From: eastern NC
Reseating the pistons should not pose a big problem. If your calipers have the lip seals, be careful when pressing the pistons back in. Open the bleeders a little and gently press the piston in being careful to ensure the lip seal goes in without inverting the lip. If they have O-Ring seals, not a problem, just gently press them back into the bore.
The problem will be if the piston has unseated the dust cover that is installed after the piston is inserted. It any of them did unseat, it may require separating the caliper halves to press the dust cover in properly.
Good luck... GUSTO
The problem will be if the piston has unseated the dust cover that is installed after the piston is inserted. It any of them did unseat, it may require separating the caliper halves to press the dust cover in properly.
Good luck... GUSTO
