[TR] TR4 brake drum problem

[Brad Kahler]

Just ran into a problem that has me perplexed.

A little background first.  This is the 63 TR4 I bought at the Mark
Josyln estate auction earlier this year.  I do know the car sat for at
least 8 years waiting on an engine rebuild.  I also know the car had
been a driver prior to that.  It also shows signs of having been
pieced together from various parts cars.

The problem: I've been working on replacing the rear axle and hub
seals.  I didn't notice the problem when I took the drums off and
pulled the hubs.  However as I start putting the parts back together
I've run across a problem where the rear brake drums don't fit over
the wheel stud shoulders.  I know the wheel studs are the correct ones
and have a shoulder diameter of .565".  The replacement studs match
the original studs in this regard.  I tried putting the drum back on
and found that it hits the shoulders of the wheel studs.  This leaves
approximately a .125 gap between the inside face of the drum and the
hub face itself.  I KNOW this just can't be right.  I measured the
diameter of the stud holes in the drums and they are about .455" in
diameter.  That's a whopping .100" difference!

One thing I did notice is there were two different lengths of flat
head screws that hold the drums in place during assembly.  A couple
were about 1/8" longer than the other two.  Each side of the car had
one longer screw.

The only thing I can think of is the brake drums had to have come from
some other Triumph car, like possibly a Mayflower.

If someone could take some measurements of a TR3/4 brake drum that
would help a lot.  What I need to know is the inside diameter on the
drums of the holes for the wheel studs.  Also what is the diameter of
the large center hole.  Mine are 2.75" which would make a nice snug
fit on the hub itself.  I think this diameter is correct.

Any help would be greatly appreciated.

Thanks!

Brad