Rear Caliper piston rust

[james accordino]

It's a generic seal.  I think it was made in Malaysia.
 I trust the co. I buy most of my bearings and seals
from.  Bearings and Drives Unlimited in Plains, PA.
Very nice and knowledgeable.  They carry dial calipers
in their pocket protectors.  Office looks like it's
right out of the 60's.  OE size is 16x24x7 if memory
serves.  I may have used 8mm depth.  I just measured
the pocket and it's almost 9mm deep.  I also thought
about the piston issue some more.  I think it'll be
O.K. even with a new rotor and pads.  There's a "magic
#", about 1/4" below the boot groove and above, that
never rides the seal.  Much more important in
determining suitability is the condition of the PISTON
(bore not as important) below this area.  It's what
rides the seal and must be fairly clean and pit free.
Also the piston/bore fit, but this isn't as critical.
The bore can be cleaned up quite a bit with a hone,
but if too loose, the piston can cock in it's bore
when fully extended and jam.  We're talking pads down
to backer and paper thin rotors, so I don't hold this
too high on the probability scale.  YMMV.  Any listers
who feel I'm the safety anti-Christ, I think new ones
are still available at $450. ea +or-.

Jim Accordino

-- Kneale Brownson <knotnook at traverse.com> wrote:
> Who has the seal and what's their part number?
>
> Thanks, Kneale
>
> At 07:36 AM 07/05/2003 -0700, you wrote:
> >Many shady "rebuilders" do this sh*t.  It's little
> >more "rebuilt" than if I sprayed it with some
> paint.
> >BTW, that seal you mention is readily available if
> you
> >go 1mm larger or smaller in depth.  The ID and OD
> are
> >common, but Audi spec'd 7mm depth.  Non stock,
> >propriety item.  6 and 8mm depths in stock.  I
> chose
> >6mm.  Also, I'm  finally going to replace the rear
> >calipers I rebuilt 82.5k miles ago.  They now have
> >267k miles on them w/ 1 rebuild.  There are some
> >questions as to how the Buna-N o-rings I used to
> seal
> >the P-brake area held up to the brake fluid.
> >Hopefully next week I'll have some answers.
> >
> >Jim Accordino
> >
> >--- Kneale Brownson <knotnook at traverse.com> wrote:
> > > At 01:03 PM 07/04/2003 -0400, denis wrote:
> > > >C'est un message de format MIME en plusieurs
> > > parties.
> > > >--
> > > >[ Picked text/plain from multipart/alternative
> ]
> > > >I have send my rear galipper to a shop.
> > > >All they did is to put a new piston, wash the
> > > galipper and change the two
> > > >big seals.
> > > >BUT didnt do anything about the area of the
> manaul
> > > brake. It seems that
> > > >they could not remove the clips inside and
> change
> > > the little seal.
> > > >!!!!!!   what a shop man...
> > > >
> > > >I think i ll do myself... not spend 150$ can
> for
> > > that job _)(*&?%$#        :-O
> > > >
> > > >Ðenis
> > >
> > >
> > > There's a circlip at the bottom of the cylinder
> than
> > > I've extracted with
> > > longish needle-nose pliers that have the tips
> ground
> > > small enough to fit
> > > into the holes in the circlip.  That releases a
> > > rather healthy spring under
> > > a flat washer, so you need to be careful.  The
> > > remaining threaded post
> > > comes out with some vigorous prying with a pair
> of
> > > screwdrivers.  That gets
> > > you to the chamber with the parking brake
> actuator
> > > that has to be removed
> > > to allow extraction of the arm that the parking
> > > brake cable attaches
> > > to.  Nobody has reported a source for the seal
> that
> > > goes in the hole the
> > > cable arm assembly sits in, but, reportedly, a
> > > replacement seal wouldn't
> > > keep the system from corroding in the future
> anyway.
> > >
> > >
> >
> >
> >__________________________________
> >Do you Yahoo!?
> >SBC Yahoo! DSL - Now only $29.95 per month!
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>


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