Oliver:
First, I am assuming that the problem was noticed only AFTER the
U Joint failed and was repaired. I am also assuming that reinstalled the
drive shaft correctly, torqued the *new* bolts properly, etc (you *did*
use new bolts and nuts, didn't you? The old ones may be bent, stretched
or otherwise damaged...) I am also assuming that you checked the drive
shaft for damage and bends (or "propeller shaft", to use the correct
English term. Ahem.)
To narrow things down a bit, do this:
When decelerating and the vibration occurs, depress the clutch
and allow the engine to drop to an idle while you coast. Does the
vibration stop? If it stops, you can eliminate the wheels and wheel
balance.
Next, put the car back in gear, and do what ever it takes to get
the vibration to occur. Note the engine RPM at which the vibration
occurs. Now put the car in a lower gear, and decelerate from the same
RPM. Does the vibration still occur? If yes, you can eliminate the drive
train, and you are looking at engine/flywheel/clutch balance.
If the vibration does not occur, you are looking at the drive
train.
Which end of the drive shaft did the U-Joint fail? If on the
tranny end, suspect a loose or failed tranny mount. They are cheap, and
you can replace them with a minimum of fuss. If the U Joint failed on
the Diff end, I would suspect something near the diff has failed,
perhaps a diff mount. I would look at replacing the diff mounts next...
It is likely that you failed to recognize and correct some
collateral damage from the failed U-Joint. The forces applied to
adjacent components when a U-Joint goes can get pretty large, and
something probably was bent, cracked, or stretched. Add to that the fact
that the Diff and tranny mounts are 30 years old and made of oil soaked,
cracked rubber, and you have a recipe for something else getting damaged
when the U-Joint let go.
Start from the failed U Joint and work your way out. Most likely
you will find something.
Cheers,
Vance
------------------------------
Cogito Ergo Zoom
(I think, therefore I go fast)
TR6 Web page: http://home.comcast.net/~v.navarrette/
-----Original Message-----
From: owner-6pack@autox.team.net [mailto:owner-6pack@autox.team.net] On
Behalf Of oliver
Sent: January 12, 2005 7:17 PM
To: 6pack@autox.team.net; triumphs@autox.team.net
Subject: vibration on a 72 TR6 very stock
Hi, all.
I'm back. there was a terrible vibration in the car at highway speeds,
and
you could see a very bad u joint on the drive shaft.
removed the exhaust, pulled the drive shaft, replaced one yoke which was
damaged and the u joints, put the drive shaft back in, and installed a
new
exhaust system. (OK. i bought the exhaust and let a muffler shop put
it
in).
car runs great; little exhaust "break in" smell.
except - up in the 60 to 75 mph, only when decelerating, there is
vibration
that you feel in your seat, both driver and passenger.
your thoughts would be greatly appreciated.
Thanks!
Oliver
|