FW: Repairing/Rebuilding Rear Calipers?

Tue May 14 13:12:22 EDT 2002

> [Original Message]
> From: Bernie Benz <b.m.benz at prodigy.net>
> To: John Cummings <jrc100 at earthlink.net>
 > Date: 4/27/02 12:42:53 AM
> Subject: FW: Repairing/Rebuilding Rear  Calipers?
>
>
>
> ----------
> > From: Bernie Benz <b.m.benz at prodigy.net>
> > Date: Wed, 27 Feb 2002 07:55:15 -0700
> > To: Steve Crosbie <scrosbie at integraonline.com>
> > Cc: 200q20V mailing list <200q20v at audifans.com>
> > Subject: Re: Repairing/Rebuilding Rear  Calipers?
> >
> > Good write-up Steve,
> >
> > One comment.
> > As I recall, maybe wrongly, lithium base grease is water soluable.
Inasmuch
> > as brake fluid is miscible with water, it then follows that lithium
grease may
> > also be miscable in brake fluid.  Therefore I use a "waterproof" boat
trailer
> > wheel bearing grease.
> >
> > Bernie
> >
> >> From: Steve Crosbie <scrosbie at integraonline.com>
> >> Date: Wed, 27 Feb 2002 00:56:41 -0600
> >> To: Peter Schulz <peschulz at cisco.com>, 200q20v at audifans.com
> >> Subject: Re: Repairing/Rebuilding Rear  Calipers?
> >>
> >> Peter,
> >> I just finished rebuilding the 200 rear brake calipers, including
> >> the e brake mechanism - with a couple of message that Bernie sent me
> >> plus some discoveries I made in the process:
> >>
> >> Peter Schulz wrote:
> >>
> >>> Bernie/Folks:
> >>>
> >>> Wide distribution due to the fact that those of us not in warm, dry
climates
> >>> suffer the malady of emergency brake cable/caliper issues.
> >>>
> >>> I tried to disassemble one of the 200's rear calipers yesterday.  I
removed
> >>> it from the caliper carrier, removed the emergency brake return
spring,  and
> >>> brake hose.  Took it to the bench.  Using the Lisle "Cube" tool to
turn the
> >>> piston out of the caliper body - removed the piston and its boot.
Removed
> >>> the inner dust shield from the piston cavity.  Looked into the piston
cavity
> >>> and saw the threaded rod to which the caliper piston is attached, and
> >>> further
> >>> inside, about three inches or 7.5 cm was a circlip that appeared to
separate
> >>> the piston compartment from the emergency brake cam and rod.
> >>>
> >>> I tried to remove this circlip using two different circlip pliers,
then a
> >>> pair of long needle nose pliers, to no avail - either the piston rod
was in
> >>> the way, or parts of the caliper body got in the way of the pliers.
I even
> >>> tried a pair of small philips screw drivers inserted in the circlip
holes.
> >>>
> >> I had the same issue finding a circlip plier that was long and skinny
> >> enough to remove the circlip holding the pistonin the bottom of the
> >> caliper body.  I bought a cheap pair of needle nose pliers with long
and
> >> skinny ends and simply filed the ends round to fit the circlip holes
> >> (got a pair that had a spring and about 4" long ends).
> >> That circlip holds a sort of cage that holds a spring under pressure.
> >> In the center of this is the threaded rod that the piston rides on.
> >> There is not a lot of room, but enough to get the skinny pliers in.  Be
> >> very careful since when the circlip is released the spring will shoot
> >> the spring holding cage (spring keeper) and itself into orbit.  The
> >> second one I did I put the caliper in a vice to steady it and held a
> >> small 2x2 piece of wood on the top of the spring keeper as the circlip
> >> was removed - much less fun, but safer.  Once the spring, spring keeper
> >> and threaded rod attached to the lower plate are removed, you can get
at
> >> the inside of this camber.  Inside this chamber you see the e brake
> >> shaft and a small jelly bean shaped thing (piece of metal rod rounded
of
> >> at each end) that is held between an indent in the e brake shaft  and
an
> >> indent in the threaded rod shaft.
> >>
> >>>
> >>> I finally surrendered, pried the cam and rod out of the caliper body
as far
> >>> as possible, sanded it, sprayed it with Wurth Rost-off, worked it
back and
> >>> forth until it would easily move, covered the exposed area with
synthetic
> >>> brake grease, and pushed the cam and rod back into the caliper body.
I then
> >>> cleaned the piston cavity, lubed the piston with brake fluid and
reassembled
> >>> the caliper.
> >>>
> >> At this point you can take out the e brake shaft and clean it up with
> >> some sand paper, coarse to fine grain (the corroded shaft is the reason
> >> the e brake lever does not return).  Also clean up the old gease and
> >> re-grease the cavity with high temp. lithium grease. The seal where the
> >> e braake shaft goes into the caliper is a simple oil seal.  I got mine
> >> at a bearing supplNow cier.  I found a TCM oil seal part # 16x24x7TC
> >> (16mm {shaft opening }X 24mm {outside diameter) X 7mm {thick}).  Refit
> >> the jelly bean and the brake lever shaft and threaded rod w/ bottom
> >> plate.  Now comes the fun - the spring and spring keeper must be
> >> compressed in order for the circlip to seat.  I used an appropriate
> >> socket on the spring keeper that covered the keeper, and allowed the
> >> threaded rod to pass through.  Then took a large C clamp and clamped
the
> >> socket down to compress the spring so the circlip can fasten.  It takes
> >> a little trial and error and you have to center the spring keeper a bit
> >> (first thing under the circlip before the threaded rod plate.  Sounds
> >> worse than it is.  Once it is together there now enough spring tension
> >> to reset the e brake even before the outside spring clip is attached.
> >> It has been working like brand new calipers for over 2 weeks - no lock
> >> up of the ebrake cable and plenty of holding power.
> >>
> >>>
> >>> Now the ebrake cam mechanism is moving easily enough that I probably
did not
> >>> have to completely dis-assemble the caliper, but I still _want_ to see
> >>> what's
> >>> going on back there...any tips advice, etc?
> >>>
> >>> BTW - I did notice that completely removing the piston from the
caliper
> >>> appeared to allow more of the ebrake caliper rod to be exposed to
cleaning,
> >>> than just prying it out and moving it back and forth with screw
drivers and
> >>> pliers.
> >>>
> >>> There are some good existing instructions and guidance at
> >>> http://www.urs4.com/technical/repair/ebrake/ebrake.html and also at:
> >>> http://20v.org/brakprob.htm#handbrake - I wanted to take it to the
next
> >>> level, however.
> >>>
> >>>
> >>> TIA!
> >>>
> >>> -Peter
> >>>
> >> Good Luck,
> >> Steve Crosbie
> >>
> >> _______________________________________________
> >> 200q20v mailing list
> >> 200q20v at audifans.com
> >> http://www.audifans.com/mailman/listinfo/200q20v

Steve,thanks your post on rebuilding the rear calipers walked me through
the job perfectly. Followed Bernies advice and got waterproof "all-weather"
boat trailer wheel bearing grease- guess what it's a lithium grease.

--- John Cummings
--- jrc100 at earthlink.net