Since TR6 has the same fundamental braking system as TR3/4 then perhaps my
recent experience might be helpful. Peyote has both front and rear master
cylinders at .75 . The front cylinder was bored to that diameter from .70
so that the same rebuild kit could be used for both cylinders. The brake
bias is set with plates that have various lengths between the center hole
(connects to pedal) and the each end where the cylinders connect. Many
people feel that 5/8" is a more rational bore for the front brake to give
appropriate mechanical advantage, but I don't mind trading pedal hardness
for easier modulation, and if you get a little air in the lines or some
other reason that your pedal goes soft, the larger bore lets you pump some
brake in while the smaller ones may not--or at least will take more
strokes. That's not a great consideration, but it's real world.
I tried a 5/8" recently because people I trust said it would work better.
Didn't like it, I'm back to .75.
One more thing, make sure while your fiddling around to use appropriate
line pressure compensation. Right now I'm using 2# in the front and 10# in
the back, and I really like it. There's no drag to speak of but the pedal
applies brake with just a tiny bit of travel. I expect an improvement in
lap times as I start being able to count on my brakes being there. I had
been pumping once or twice to get a firm pedal. Not a confidence builder.
-----Original Message-----
From: Hugh Barber [mailto:tr6nut@sbcglobal.net]
Sent: Thursday, July 31, 2003 8:48 PM
To: Fot
Subject: Brake MC sizes?
Hi All,
I'm replacing the Brake Booster/Master Cylinder with dual master cylinders
on the TR6 vintage racer. Does anyone have any suggestions as to which
sizes would be a good starting point? I know that I could probably sit
down and figure out something close, but I figured if somebody might have
already done this, why reinvent the wheel?
Thanks,
Hugh Barber
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