Assuming that this is a type 16 caliper, they are all pretty much the same.
There are 2 different style pads, "big" pin & "little" pin, dimensionally they
are the same, and there are differences in the friction material shape. Some
are rectangular, some are the shape of the lower half of a hexagon.
These cars need a pad with a taper because they run hotter and wear faster
towards the OD.
If you're running a full rectangular pad (same shape as the backer), it's gonna
wear towards the OD and get a taper in it in-to-out, and that's when the
pad/piston alignment gets all poopo-kaka, the pedal gets long, etc.
I'm not suggesting that there isn't an issue with what you have discovered but
the pad backer ends to the caliper clearance isn't a real close tolerance point.
Hope you get it sorted.
Glen
ps- Also I might be misunderstanding the problem...
-----Original Message-----
From: DAVE HOGYE via Fot <fot at autox.team.net>
To: Friends of Triumph <Fot at autox.team.net>
Sent: Tue, Jul 10, 2018 5:52 pm
Subject: [Fot] brake pad and rotor discovery and update
Hello Friends,
I have been finding out quite a bit about the unusual and developing front
brake pad, rotor and caliper issues that I have discovered on my TR3.
What I found was that the Carbotech CT-57 pads were causing the problem.
The supporting or backing plates of the pads had been ground down at Carbotech,
far under the normal plate width that I measured in 4 other production pads
that I have on hand. Besides that, they were not ground down squarely.
This allowed the piston to take tremendous side load under braking causing the
uneven and diagonal wear pattern in the pads. This also caused the rotor to
contact the caliper as the pads took on heavy uneven wear.
The slot in the TR6 caliper is 3.095" and the four non-Carbotech pads sets have
a plate width of no less than 3.082". The Carbotech plates have an out of
square measurement of 3.030-3.050". That's as much as .065" clearance in the
caliper slot.
The plates have too much clearance. I found that a maximum of .010" backing
plate to caliper slot clearance is more normal. One set of pads have only
.005" clearance.
Furthermore, the corners of the Carbotech plates and pads were ground down far
enough that the lower end of the pads hardly made contact with the caliper slot
allowing more stress on the caliper piston.
I have been going back and forth with Carbotech on this matter and I will be
sending back the badly worn set along with a brand set that have the same
production issues. I bought the two sets at the same time last August.
What I found is that any backing plates that show evidence of sanding or
grinding marks should be measured for proper clearance, but that really, there
should be no sanding or grinding marks...ever.
All of the other pads I have show no evidence of sanding or grinding marks.
The previously shaped friction pads are cleanly attached to the backing plates
and the backing plate is revealed around the friction material. Only the
backing plate makes contact with the caliper slot.
It looks like I have to find another race pad supplier.
Thoughts?
Dave H.
831-234-4928
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