brake conversion-wilwood

Sun May 12 00:24:32 EDT 2002

I'm not at ALL with you, I doubt wilwood is too.  Shims, quite frankly are a
great idea for a couple reasons.  First, as a pad wears, more of the piston
is exposed to the elements in a non sealed caliper.  This means (SS or not)
that surface rust forms on the piston, the further the pad wears, the more
rust area will form.  As this crud gets scraped off, wear of the piston bore
occurs, more crud = more potential wear =increased service interval.

WRT dust sealed calipers, as the pad wears, the piston is pushed further from
rest position.  The further a piston travels to make pad/rotor contact, the
less stable the piston becomes, and from a strict leverage standpoint, the
further a piston is extended, the more the caliper tendency to twist.  This
is especially true of floating calipers, but it certainly applies to fixed
calipers as well.  As a caliper twists or a piston kinks, the more heat is
generated.  As heat increases, bye bye dust seal,. btst many times especially
on G60's

I'm not really sure which corner you are presenting your opinions from.  It
would appear that keith is speaking of aftermarket fixed caliper arrangements
with no dust shield.  You are speaking of either aftermarket fixed caliper or
stock floating calipers with dust shields.  IN either perspective, the less
total piston travel you have, results in ALL good things in terms of service
life, btdt.

When you speak of ANY aftermarket brake combination, shims are a key factor
in them.  For more on this ck the archives, I went a round with MGW on this
exact point.  Bottom line:  The less piston travel (*however* you achieve it,
shims are the easiest way) over the life of a given pad, the less service the
caliper will require.  Remember too, that if you gander about WRT pad
thickness vs backing plate/shims, the measures are all over the map.  Close
attention should be paid to the piston extension recommendation, especially
as you clamp "non app" rotors (ie big reds on A8 rotors for example)

Bernie, I service a LOT of aftermarket brake setups on quattros, some better
n others.  But here, bottom line, I'm just not with you.  With many of the
wilwood applications, or anyone going after 4x4 pot calipers, you really
*have* to do the shim routine, or you will find yourself out of master
cylinder quickly.

my .02 arbitraged thru the peso
'87 t44tqw mit big reds (dust booted)  and shims
In a message dated 5/11/02 8:49:30 AM Central Daylight Time,
b.m.benz at writes:

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Scott and Keith,

My point is based on the fact that reliable 0-ring and Quad ring seals must
be protected from the ingestion of even small particles and quanities of
That's why shocks and all industural hydraulic cylinders use rod scrapers as
the outside protection from such intrusions.  Inasmuch as this road grime
cannot be cleaned from the piston surface, short of disassembly, within the
small piston to bore clearance and the sharp accute angle formed at seal to
piston interface, it will be ingested if the piston is forced back into the

Mark's response from "Todd Howerton" <ToddH at>
Subject: DUST SEALS indicated that Wilwood pistons are stainless steel and
he did indicate that some use Keith's "trick" in servicing pads, but hardly
a recomendation, IMO.  Therefore, from a seal reliability standpoint, in the
absence of dust boots the piston should never be forced back into the
caliper without disassembly and cleaning.  And there is absolutely no good
reason for doing so.  A little ss hanging out in the breeze incours no harm,
but don't abuse your seals!


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