Randall,
Thanks. I am leaning towards the 0.70, which I will duly note in my car's
log book along with all the other changes I have made (like the lifter
clearances at 0.16 and 0.18 for my fast street cam), Luk Diaphragm clutch,
etc. I may even stamp 0.70 on the outside of the master cylinder, so I
don't curse myself out one day. <HG> Yeah, I'd be pissed if I bought a
rebuild kit, clutch or master cylinder, and it was the correct one, but it
didn't fit. That's why I keep a detailed logbook. Without it I would be a
DPO, Damned PRESENT owner!
My brakes are fine. Just as my seats now rise about and inch and a half as
they slide forward, I am looking to decrease the pedal pressure for my
petite wife, who also autocrosses the car. She is Ok with the brakes as
they are, but less pedal pressure required would be better. I don't know
about your car, but I get full pedal pressure very high up on the pedal
stroke. I could easily accommodate another 3 inches of pedal motion. That
said, I believe 0.70 is the limit, based on a 0.75 "correct" bore.
For the purists out there, I have made many modifications to my TR3, but
very, very few that couldn't be changed back with just a spanner and/or
replacement part.
Later,
Jack
> Jack :
>
> 0.75" is the correct bore. 0.70" will clearly work, since Triumph
> switched to that size on the later TR4 (but someday, someone will curse
> you as a DPO, when he/she tries to install a standard rebuild kit <g>).
>
> I'd be reluctant to try the 0.62" on the street, 1st because I've never
> felt the pedal pressure was too high (perhaps something else is wrong
> ?), 2nd because running out of travel at the wrong time can be most
> unpleasant. Since the ratio is the square of the diameters, the 0.62"
> master would have almost 50% more travel.
>
> Randall
> 59 TR3A daily driver
>
> Jack Brooks wrote:
> >
> > Scions,
> >
> > I am ready to purchase a $64.95 Girling Brake Master cylinder from the
> > TrueChoice catalog for my post 60,000 TR3A. (Yes, they are Girlings and
> > they are inexpensive.) They list three bores at 0.75, 0.70 and 0.62
> > diameter. Can anyone clarify which one is the correct size? I
> have not yet
> > pulled my old one yet, as it is just starting to fail.
> >
> > Also, has anyone used a smaller bore master cylinder to decrease pedal
> > pressure? I realize the smaller bore will move less fluid per
> inch of pedal
> > travel, requiring more pedal travel to exert the same braking
> force, but the
> > difference should be OK, based on the allowable pedal travel remaining
> > before bottoming.
> >
> > BTW - the Truechoice URL is http://www.truechoice.com or call
> 1-800-388-8783
> > for a catalog.
> >
> > As always, thanks for your help,
> >
> > Jack Brooks
> > 1960 TR3A
> > 1974 Norton 850 Commando
> > Hillsdale, NJ
>
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