New rear caliper piston retracts too much

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Jan 23, 2015 | 05:19 PM

turbogoat

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AudiWorld Junior Member

Joined: Dec 2014

Posts: 45

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New rear caliper piston retracts too much

I replaced and bled both rear calipers and I am using Pentosin DOT 4 fluid. The sliders are new as well and they move freely. After releasing the pedal, the piston on the driver side pulls away from the pad nearly 1/8" over the course of about 10 seconds. Double-pumping the pedal is then required to achieve firm contact.

The passenger side behaves normally, relaxing only slightly when pressure is removed.

Do I need to turn the piston out to take up most of that clearance before placing the caliper assembly over the pads?

I've replaced scores of calipers over the course of my existence, including some of the integrated parking brake style, but never before have I encountered this specific issue.

Thoughts?

Regards... Mike

Last edited by turbogoat; Jan 23, 2015 at 05:22 PM. Reason: Incorrect grammar

Jan 24, 2015 | 09:59 AM

Mike Atkisson

AudiWorld Member

Joined: Apr 2005

Posts: 442

Likes: 0

From: Tucson, AZ

Your car will "auto adjust" that piston out farther by pulling the e-brake handle a few times. That adjustment mechanism is the reason that you have to turn the piston while pressing it in.