You Wrote:
Date: Sun, 20 May 2007 12:50:37 +0000
From: banc8004@comcast.net
Subject: [TR] TR4 C-type caliper rehabilitation
I am in the process of rebuilding my brakes. I have a number of jobs to
complete (new flex lines, replace rear pads etc.) On my front calipers, I
see that I have uneven pad wear. One pad in each caliper is twice as worn as
the other, so for one reason or another, on piston is applying less pad
pressure than its sister on the other side of the disc.
To minimise down time, I picked up a set of calipers on ebay. My hope was to
refurbish them with new pistons, piston seals and rubber seals, and then
swap out the originals...and maybe rehabilitate those for a future need.
Anyway, I am faced with pistons I can't budge. There is some corrosion, but
not a lot, really.
I have been soaking them with penetrating oil for a day or so, to no avail,
as yet.
Does anyone have a tip for me to get these pistons out so can begin the
rebuild?
If not, I guess I have a couple of Triumph artifacts to enjoy.
Brian in Valley Forge
TR4 1963
CT14455 L
Brian,
Tolerances are tight between the piston and the sleeve, and attempts to
apply forces that may be off-axis rarely work. Try the following:
1. Place a thin piece of wood between the two pistons, allowing < inch
or so of an air gap,
2. Put a flexible tip at the end of your air-line pistol grip,
3. Close off the bleeder valve,
4. Press the tip firmly into the hole at the top of the caliper body
left by the vacant hydraulic line,
5. Give the caliper assembly a short burst of high-pressure air; I
usually keep my compressor lines at 90 psi, but even half of that will work,
6. Both pistons will pop, striking the piece of wood (remember the
piece of wood?) on each side.
This method is benign, causing no damage to the pistons or the cylinders.
Rick
TR3A
TS 68101 L
Richard Chandler
PropTech Marine Propellers
13239 NE 20th Street
Bellevue, WA 98005
425 643 0155
www.prop-tech.com
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