Well I have been busy with my drive shaft. It started when......
Noise from rear. Inspected U-joints. Suspected rear drive shaft joint.
Removed. Found it to be OK. But now required replacement due to bad
seals. Replaced the U-joint with new hardware.
Shaft now out of balance. Re-balanced using two stainless steel hose
clamps. Jacked up the car. Removed the rear wheels and brake drums.
Placed one hose clamp around the rear of the shaft with adjusting screw in
alignment with U-joint grease feting. Run up engine in forth gear to 70
mph. Noted vibration. Moved clamp adjusting screw around the shaft,
keeping track of the vibration change. Used this method to find the "low"
or "light" point. Reasoned that the best vibration reduction was the light
point. Light point was determined to be at about 310 degrees. The grease
fitting being 0 degrees and count up clockwise as observed from the front of
the car. placed a second hose clamp next to the first with the adjustment
screws in alignment. Ran up the engine to note vibration (increased).
Then began to move each clamp 10 degrees each, one clockwise, the other
counter clockwise. Found the best, least, vibration with one clamp at 260
degrees and the other at 10 degrees. Tightened both clamps very tight.
replaced brake drums and wheels and tested drove car. Found no
discernible vibration due to drive shaft from 0 to 90 miles per hour in
either acceleration, compression or coasting.
This method is only subjective in nature. That is to say the I have no
instruments to test or quantify the vibration or lack there of. But before
the procedure there was unacceptable shaking and noise. After only what was
there before I "fixed" the U-joint.
The original noise is still coming from the rear but I now have new theories
about its origin.
Once I got in the rhythm of testing for vibration I think that my method was
even faster than removing the shaft and taking it in to be professionally
balanced. It was certainly cheaper.
This method of balance was only possible because I only had to deal with one
end of the shaft. The possibilities are much more numeous if trying to find
a balance point for both ends at the same time.
Sliding smoothly somewhere sensational for the season....
Tom Howard
'72 Triumph GT6 Mk3
(and a good bit of USA iron)
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