Rear Brakes on an Audi A3

[Ford Prefect]

I needed to replace the brake pads front and rear on my wife's Audi A3. The front were easy but I am having a real problem with the rear ones.

I cannot get the piston to retract and suspect this has something to do with the parking brake being self adjusting. I have removed the bolts holding the caliper in place but because I can't get the piston to move back more than about 2mm I can't even get the caliper off the disk because there's an edge on the disk. I removed the parking brake cable from the back of the caliper but still the piston refuses to retract. There isn't even a Haynes manual available for the bloody thing yet!



Can anyone advise if I'm barking up the right tree with the parking brake idea and if so Pleeeease tell me how to get it to release as there isn't much left of the pads so I'm running out of time!!!

[funkihamsta]

Maybe this has some relevance:
(Cut and pasted from another forum)
"Rear disc brake caliper has to be retracted when fitting new pads using an unconventional method - don't wind the piston back as you would normally do. There is a hex plug on the rear of the caliper - remove this an wind the piston back using the drive located below this plug. Otherwise the calipers will be rendered as scrap!"

This was in reference to a 480 volvo, which was ahead of its time by having the uncoventional/awkward as feck method described above..It also had a self adjusting parking brake. l only hope that your efforts thus far have not rendered your calipers as scrap!!

Good luck.
funkihamsta


>> Edited by funkihamsta on Sunday 30th June 09:13

[Dave_H]

quote:I cannot get the piston to retract and suspect this has something to do with the parking brake being self adjusting. I have removed the bolts holding the caliper in place but because I can't get the piston to move back more than about 2mm I can't even get the caliper off the disk because there's an edge on the disk. I removed the parking brake cable from the back of the caliper but still the piston refuses to retract.

I've never attempted this on an Audi, but a lot of rear caliper pistons are threaded - i.e they don't just push in push out like the front ones, they "twist" out to self adjust so the handbrake still works as the pads wear down.

If this is the case on your Audi you'll see that the piston has a raised cross or edge of some sort on the edge that meets the pads, this is for the "piston winding tool" (I doubt that's the correct name )That fits on to it to wind back the pistons. The tool is the shape of a cube and fit's on the end of a ratchet, they normally have several sides of the cube with different shapes to fit most common makes of car. If you go to a decent motor factor that sells tools they should know what you're talking about. I cant imagine it would cost more than £20 it's about the size of a 20mm half inch socket. Once you've got this ratchet attachment getting the pistons back in is a doddle

Cheers,

Dave.

>> Edited by Dave_H on Sunday 30th June 14:15

[Ford Prefect]

Dave and Funkihamsta, many thanks for the replies. I think you have hit the nail on the head so to speak. I did notice a flat edge on either side of the piston and now I know what it's for. I will get the tool and hopefully I should be back in business.....brilliant.

John.