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View Full Version : OEM Rear Caliper Q



jaredpgh
04-03-2007, 01:11 PM
I just ordered new rear pads and rotors for my A4, and got to thinking about our rear calipers. I've replaced the pads in the past, which required the twisting motion to help them retract, and wondered, why is this necessary? I realize that it probably has something to do with the self-adjusting mechanism inside, but is the piston threaded? This is especially puzzling because the last time I retracted the pistons, I used a brake cube on a 3/8" ratchet. I had a hard time getting the pistons to retract, and the piston would rotate and rotate for awhile before it pulled in. Luckily I now have the Harbor Freight tool to make things easier, but I am still curious.

ModifiedA4
04-03-2007, 01:48 PM
two words: parking brake

jaredpgh
04-04-2007, 07:24 AM
eight words:

that's not a very good explanation.

please elaborate

tomustang
04-04-2007, 08:38 AM
The parking brake is intergraded with the rear caliper setup, all the calipers for that design need to be screwed back in instead of pushing

jaredpgh
04-04-2007, 09:12 AM
The parking brake is intergraded with the rear caliper setup, all the calipers for that design need to be screwed back in instead of pushing

yes, i understand that. but what is the mechanism inside that requires a twist during retraction? if you just stuck it in a bearing press and squeezed the piston back in, would your brakes work but not the parking brake? is there some auto-adjustment mechanism? is it threaded?

ModifiedA4
04-04-2007, 11:58 AM
one word: SEARCH

tomustang
04-04-2007, 12:57 PM
yes, i understand that. but what is the mechanism inside that requires a twist during retraction? if you just stuck it in a bearing press and squeezed the piston back in, would your brakes work but not the parking brake? is there some auto-adjustment mechanism? is it threaded?

It's just how it's designed, maybe to save space

don't know why people continue to say 'search' this is a tech section and if everyone did a search there wouldn't be as many threads

jaredpgh
04-05-2007, 07:14 AM
gotta love the search nazis. there is absolutely NO info on the forums about the internal design of the calipers. tons of info about where to get the tool (i got mine from HF two years ago for like $23) and how to retract them, but nothing germane to my question. a sincere thanks to tomustang though, at least you tried to answer the question instead of just being a smartass.