My 1976 Triumph TR6 has 33,700 miles (original) on it and I have just had
some mechanical work done on the brakes, bushings, and stiffer springs
(from TRF) including new brake rotors, stainless steel brake jumpers, new
discs, new rear brake shoes, aluminum steering guide (from TRF), and
electronic ignition. Also, the rear differential mounting was reinforced
and cracks welded.
I don't know whether everything is now stiffer in the suspension or what,
but now there is a stronger pulsation of the brake pedal and shaking when
normally (lightly) putting on the brakes --- sometimes. However, when
braking hard, the brakes work fine without any shaking of roughness of the
car. While driving under throttle, lightly touching the brake pedal
generates a pulsation. Before the repairs to the brakes and suspension,
only occasional shaking was noticed. The car drives and rides normally up
to 70mph or so (highest that I tested it today) so the general balance of
the wheels, tires, and suspension appear to be OK.
The timing for this is not good since I wanted to take the TR6 for a few
laps around VIR (http://www.virclub.com) tomorrow (Saturday, 09dec2000).
The mechanic (very good sports car and formula racer mechanic) thought that
machining the rear brake drums might help --- it did not.
Our possible thoughts are as follows:
1. The front brass trunnions have slight play. Could this be the source
of the vibration when the car weight is distributed in certain situations
under light braking???
2. Something in the suspension or brakes???
3. Hydraulic brake cylinders and/or servo unit may be generating transients???
Does anyone have any ideas, suggestions, or experience in this situation????
Thanks for your help.
Bob Sexton
sexton@starmark.net
804.792.0167
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