At 01:50 PM 4/25/2000 -0400, Gordon Bird wrote:
>.... Rear drivers side brake (drum)is kinda on or off. It is the first to
lock, even prematurely. Car (MGA) stops straight and sufficiently.
Noticable at very low speeds. Without undo pedal pressure, that wheel will
suddenly lock. ....
This one had me baffled for a while a couple of years ago. I had a RF
wheel locking up at at about 10 mph with only light pedal pressure, and
everything inside the brake drum was in perfect condition, new cylinders,
clean and dry, etc, and the brake drum was also smooth and concentric
within specs. Out of shear frustration I had the front drums turned
anyway, and the problem went away.
Appearantly a lot of heat cycling over the years changes the metalurgical
structure of the friction surface of the drum, possibly causing the
collection of carbon nodules and enlarging the grain structure of the metal
near the surface. The shop that turned the drums said they had to take a
finishing cut at least 0.015 inch deep to keep the cutting tool from
chattering. Now the drums are near the maximum working diameter, but at
least all is well with the world again.
Barney Gaylord
1958 MGA with an attitude
http://www.ntsource.com/~barneymg
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