Rear caliper problems! HELP!

LAndy Posted a lot Posts: 1,061	Rear caliper problems! HELP!LAndy @greavesy
	Jun 18, 2012 16:39:48 GMT Select Post Deselect Post Link to Post Back to Top
	Afternoon all! Can someone please help me! I'm currently working on the brakes on my 1993 Audi 80. Basically on the rear I've done: New seals. - Took out the piston, changed the dust cover seal and the seal between the piston/bore of the caliper. New lines. New discs. New pads. New fluid. I've bled the system today and all of the brakes are working apart from the rear NS. With the brake pedal pressed it is still possible to spin the disc. If you pull the handbrake with a bit of fight you can still move the disc. I've tried the caliper on the OS and it still doesnt work so I know there isnt a problem with the lines. With the caliper off the car, if I pull the lever for the handbrake it acts like a ratchet and pushes the piston out, though it doesnt return when let go? Meaning the piston gets further out everytime I pul the lever, this doesnt seem right to me?? I've tested the caliper, still attached the lines but using a block of wood instead of pads/disc. and the piston simply doesnt move. Using a piston rewind tool the piston seems easy to move both in and out fairly easily so whats happening? I hope this all makes sense and someone can point me in the right directon! Regards, Andy
	Previous retros: 92 AX GTi 92 Scirocco Scala 94 80 sport 87 Golf Cab GTi Current retro: 1965 Clark Cortez YouTube Website Instagram

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BenzBoy Probably posted too much Posts: 17,940 Club RR Member Number: 7	Rear caliper problems! HELP!BenzBoy @benzboy Club Retro Rides Member 7
	Jun 18, 2012 19:51:51 GMT Select Post Deselect Post Link to Post Back to Top
	It seems to me like the piston isn't adjusting itself after winding it back. When I did the rear brakes on my Mk3 Golf (I think the calipers might be the same? Or if not, similar), the handbrake took a few uses in order to ratchet up the pistons. It would pull right up to the top of its movement a few times before the pistons got into position. I'm assuming you've rebuilt both calipers - or was it just the one? If it was just the one side, I'm wondering if the already adjusted caliper is stopping the handbrake from moving far enough to ratchet the rebuilt piston into position and I had a decent handbrake. Or could the ratchet mechanism be seized? I've encounted this on the rear calipers of a Mk2 Golf. Jun 18, 2012 16:39:48 GMT LAndy said: With the caliper off the car, if I pull the lever for the handbrake it acts like a ratchet and pushes the piston out, though it doesnt return when let go? Meaning the piston gets further out everytime I pul the lever, this doesnt seem right to me?? This seems normal to me - the piston will ratchet up until it encounters the disc. The piston movement during braking is very very small, so with the handbrake released there won't be much visible movement in the pistons / pads. I'm just throwing ideas out there really! Someone might come along with the definite answer...
	Last Edit: Jun 18, 2012 19:58:12 GMT by BenzBoy 1975 Mercedes-Benz 200 1989 Nissan Patrol OM606 conversion 2015 Volkswagen Caddy Maxi

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keithyboy Posted a lot Posts: 2,884	Rear caliper problems! HELP!keithyboy @keithyboy
	Jun 18, 2012 19:54:55 GMT Select Post Deselect Post Link to Post Back to Top
	Working the lever does usually move the piston out but not really back in again. What happens when you try to bleed that corner? Is fluid coming though the nipple.
	Jaguar S-Type 3.0 SE

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workinprogress Part of things Posts: 211	Rear caliper problems! HELP!workinprogress @workinprogress
	Jun 20, 2012 12:56:18 GMT Select Post Deselect Post Link to Post Back to Top
	sounds to me like the piston ratchet is knackered or not located properly during the caliper service...if you can borrow a caliper try it,,,if not a new caliper will be needed
	if at first you don't succeed...use a gas axe!

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