Hanging rear caliper

Bernie Benz b.benz at charter.net
Sat Apr 16 11:54:40 EDT 2005

Implying that the external portion of the piston, outboard of the seal,
could corrode, right?  If so, it wouldn't cause any problem until one tried
to retract the piston for new pads.  Any disruption in the smooth chrome
plated piston sealing surface signifies end of life.


> From: Kneale Brownson <kneale at coslink.net>
> What I wrote, Bernie, was that there COULD be corrosion on the piston,
> especially if it was extended from the cylinder quite a bit by pad wear.  I
> said nothing about it falling out of the cylinder.  DFIIIAB.
> At 08:17 AM 4/16/2005 -0700, Bernie Benz wrote:
>> Come on, get real, Kneale and Peter!
>> Pistons can not extend far enough to drop out of the caliper seals, unless
>> one forgets to install the rotor.  Using the passive pad wear detectors, I
>> routinely wear my pads down to where the backing plates touch the rotor
>> ridges.  Further, there is no piston "cocking force", tendency for the
>> piston to cock or jam within the caliper bore.  They do get sludged up form
>> lack of fluid change though.
>> Bernie
>>> From: Kneale Brownson <kneale at coslink.net>
>>> So, have these gone unserviced for a year and a half?  Did you use new,
>>> OEM, or some rebuilt stuff?  You might have corrosion on guide pins or the
>>> caliper piston, especially if the pads are worn enough the piston is
>>> extended quite a bit.
>>> From: Peter Schulz <pcschulz at comcast.net>
>>> Couple of thoughts...
>>> Ebrake mechanism not fully releasing, or the pads are worn down to less 1/4
>>> depth- and the caliper cylinder is extended to the point where its binding
>>> on the cylinder walls.  If the Ebrake mechanism and cables are releasing
>>> and functioning properly, drive the brake piston completely back into the
>>> caliper.
>>> -Peter

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