Audi rear brake calipers won't wind in.

[jac-in-a-box]

Wife has just bought an '02 60k mile Audi TT which had a duff rear ABS sensor. To replace sensor I removed caliper and disc for access to sensor. I also removed the handbrake cable from the caliper again for access to sensor.

When I put it all together I rotated the handbrake operating lever on the caliper so I could get the cable back on - mistake! The piston moved out and the caliper would not fit over the pads. I borrowed a wind-back tool from a friendly local garage, but the piston refuses to move (it's a right hand wind in piston, so not winding the wrong way!)
Applied enough pressure to start bending the tools winding handle but no joy.

Eventually had to "thin" the pads to allow caliper to be refitted. Pads are due replacement along with discs so I'm guessing the piston is close to its maximum extension.

Any thoughts as to why this is happening. Local Audi specialist is teling me it's not worth attempting to rebuild calipers and I should fork out £120 for a new caliper (no doubt the other will need work too)

I can get a repair kit from "Bigred" to cover both calipers for £25'ish and feel competent enough to give it a go...however, slightly worried that there may be something amiss in the caliper that's preventing it from being wound in and I'll be chucking 25 notes away.

Any thoughts and advice would be welcome please. I'd also appreciate being pointed towards a decent quality wind in tool. All I can find local to me are these "cube" type tools which don't seem to be favoured.

Thanks!

[mk2 24v]

if you can, ive sometimes found that winding the piston the opposite way 1st helps
thats providing the tool actually allows it, as most are too fat to fit the caliper when the pads are that low

oh, and a squirt with something like wd40 around the piston seal and letting it soak for a bit may help

[ShaunTheSheep]

Undo the bleed nipple and try winding it back - if this works it's a sign of a bigger problem! These do need a fair bit of pressure but not to the extent you'd need to bend the handle.

[jac-in-a-box]

An update and thanks for the suggestions...all works fine and caliper rebuilt for £12.50

Bought the seal kit from BigRed - comprehensive too; main seal, dust boot, sliding pin boots and various O rings for the handbrake mechanism.

Bought a Laser windback tool, much sturdier than the tool lent to me by local garage. Nice big hex on the end to fit a socket and breaker bar on to - and it still wouldn't move than a few degree's either way. Soaked the piston and seal area with penetrating fluid; and no, it wouldn't move. Threw it in the oven for 30 mins thinking the caliper body being aluminium and the piston steel I might be in with a chance with some gentle expansion - but no

The only way the piston was coming out was by using the handbrake operating lever on the caliper, pull it down and the piston popped up a little with each successive pull, eventually it just lifted out. It wasn't as I thought a case of the piston being seized in the bore!

There was however, a little swarf on the thread that screws into the back of the piston - maybe that was stopping it from screwing in? Piston and bore were unmarked.
Anyway after a thorough clean, it was a doddle to put back together with the seals. A pressure test with an old master cylinder and pedal box proved it to be tight, back on the car and it's good as new...£120 for a new caliper? No; I'll chance my few quids worth of seals thank you

Thread on rebuild here (not mine) same style of caliper with great pictures:

http://forums.audiworld.com/showthread.php?t=27701...

[Nick3point2]

mk2 24v said:

oh, and a squirt with something like wd40 around the piston seal and letting it soak for a bit may help

Under no circumstances should you do this, the seal with go baggy and will need changing.