[6pack] Clutch Master Cylinder diameters

[Robert Lang]

Hi,

The early TR6's had a .75 bore clutch MC. They were "heavy", meaning you 
need more leg power to push and hold the clutch. At some point (I can't 
recall when, but I'll guess at CC50000) the factory switched to a .70 bore 
clutch MC. This setup feels "lighter" meaning not as much leg pressure is 
required to push the pedal down.

The .75 replacement clutch MCs got very expensive due to an imbalance 
between supply and demand. This is odd because there weren't as many early 
cars made as the later cars (69's account for less than 1/8 or total 
production or TR6). It's doubly odd when you consider that you can buy a 
generic hyrdraulic Girling MC from a variety of sources for fairly cheap 
money. But a lot of Triumph enthusiasts that are looking for exact 
replacement seem to gravitate to the places that charge more for the 
parts...

The wierd thing about all the TR6 hydraulics is that they use a wierd 
pedal ratio. I can't recall exactly, but 9:1 pedal motion pops into my 
thoughts on the matter. I recently (2 years ago) switched my race car 
hydraulics from the stock setup to a Wilwood / Tilton setup (you can buy 
this stuff at most race shops) and the resulting clutch setup is very easy 
on the leg. As part of this process, I dumped the vacuum assist stock 
brake MC and I was concerned at how much pedal pressure would be needed to 
lock up the brakes - they work BETTER with the new setup!

But back to the point - if you're looking for period correctness, you go 
with scarce as hen's teeth clutch MC or you go to alternate supply houses 
to get a "deal" on a .75 MC or you do what 99% of the DPO's out there have 
done and switch to th e.70 clutch MC.

c ya,
rml
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Solo Chair 2008       TR6 40 F Prepared        |  Triumph!
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