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SC rear caliper dragging
Bought the car a year ago, PO upgraded to carrera calipers, SS brake lines etc. when driving last year right rear caliper was dragging and things got real hot. I removed the pads, excercised the calipers and it seemed to work fine. While doing some winter time tinkering and the car up on jack stands, I again notice the same wheel is dragging, not as bad as before but definetely stiffer than the other side.
Any suggestions or does this mean the caliper (which shouldnt be that old) needs a rebuild? If yes, should I do both sides at same time? I am bit of a noob but not afraid to tackle some stuff - suggestions are most welcome. Thanks in advance
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82 SC Triple Black |
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02-28-2015, 09:31 AM
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Member 911 Anonymous
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did PO, install a proportioning valve like the 3.2's have?
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'85 Carrera Targa Factory Marble Grey/Black * Turbo Tail * 930 Steering Wheel* Sport Seats * 17" Fuchs (r) * 3.4 * 964 Cams * 915 * LSD * Factory SS * Turbo Tie Rods * Bilsteins * Euro Pre-Muff * SW Chip on 4K DME * NGK * Sienes GSK * Targa Body Brace PCA/POC |
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02-28-2015, 09:41 AM
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Project Addicted
Join Date: Jul 2012
Location: Eastern Shore. MD
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If you have them rebuilt, do both at the same time.
Eric a PMB works wonders and will return them looking fabulous. Jon
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Jon 1966 912 1976 911 3.4 Backdate Project 1986 944 |
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02-28-2015, 10:09 AM
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Just dug into the pile of old receipts and it appears the rears were restored SC calipers (parts number 911 352 907 00)installed in 2007 but not many miles ago (approx 12,000). The fronts received new carrera calipers, rotors etc. I see no mention of a Proportioning valve
As I was just excercising the pistons I cant get the inner one to move when depressing brake pedal, only the outer one
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02-28-2015, 10:20 AM
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Member 911 Anonymous
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Oh my, then it is time for a rebuild, not difficult at all.
But before that, I would disconnect the line to those calipers to see if the line are flowing freely. SCs did not have the proportioning valves, so you are good there. It appears the rear piston is binding.
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'85 Carrera Targa Factory Marble Grey/Black * Turbo Tail * 930 Steering Wheel* Sport Seats * 17" Fuchs (r) * 3.4 * 964 Cams * 915 * LSD * Factory SS * Turbo Tie Rods * Bilsteins * Euro Pre-Muff * SW Chip on 4K DME * NGK * Sienes GSK * Targa Body Brace PCA/POC |
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02-28-2015, 10:31 AM
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Location: Mississippi
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1) Find a nice hill or incline.
2) Let the car roll backwards or forwards a bit while "stabbing" the brake pedal repeatedly. Don't hit the pedal hard and hold it but just stomp and release several times. Worked for me in the past. |
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02-28-2015, 10:33 AM
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Last time bled the brakes the fluid 'flowed' fine. I also have the old calipers - I will take the time to rebuild it first , been curoius to do it anyways
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02-28-2015, 10:47 AM
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Change the brake hoses. All of them. I'm going to suggest OEM rubber.
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02-28-2015, 11:02 AM
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Why should I replace all the brake lines? They were all new when the calipers were replaced in 07
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02-28-2015, 12:17 PM
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not all the brake lines, just the rubber part. they are known to swell and not permit the caliper to retract. they are cheap and then you can rule that out as a problem
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Jason 81 SC 97 328is 87 Jeep Comanche (RIP) |
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02-28-2015, 12:38 PM
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Actually the SS lines can swell up too. Dragging brake is classic symptom of swollen brake lines. And the OEM rubber lines are much better than non-DOT SS lines.
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02-28-2015, 06:43 PM
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ok, but just so we are clear, the outer piston moves freely in and out, the inner one seems seized. if the problem was in the lines, wouldn't both pistons be affected?
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02-28-2015, 08:15 PM
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OK, I see. I guess the only way to find out is to take the pistons out and replace the rubber seals. That's an easy job. If the pistons are bad, then you can get new ones at Zims in Texas. Nice people and great parts.
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02-28-2015, 09:37 PM
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Cool, thanks. Will order up a rebuild kit and see how it goes
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03-01-2015, 06:47 AM
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Join Date: Aug 2012
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When you pop the Pistons, run your finger inside the bore and feel for a ridge. It will need to be removed or you'll have the same problem. Frankly, I would send them out for a professional rebuild which will include replating.
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"Too much is just enough." |
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03-01-2015, 06:53 AM
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PMB performance
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03-01-2015, 10:49 AM
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Quote:
Yes, I do much the same. I go flying backwards, full revs in reverse, and stomp on the brake a number of times. It's a good first attempt at fixing the problem before starting to pull things to bits. |
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03-01-2015, 10:57 AM
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The other thing that might work is to take the inner pad out, and slide a wood shim that is about the thickness of the pad plate in there and hit the brakes while on the jackstands. Might be safer than rolling down a hill with known bad brakes.
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03-01-2015, 11:36 AM
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hhmmmmm, i like simple solutions. will giver a whirl in next few days and report back. I supposed the idea is apply force to the piston in a opposite direction and hope to free it up.
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03-01-2015, 12:40 PM
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Porsche 911SC
Marble Grey
