Bad vibrations

["Dean Lewsam" <deanlew@domain.elided>]

Dear Stag Digest Members,
I have just got my car back after being off the road for 6 months or so
having a full engine rebuild. I must say it is great to be back on the road
and all initial indications as to the work performed are positive!!

But back to an older problem......

When I first purchased my 76 Stag, I noticed it has quite a noticeable
vibration (more seemingly from somewhere in the drive train) at speeds over
100km/h (not really noticeable from 0-80km/h). After some initial
inspections we did most of the obvious things such as wheel balance (front
and rear) and new tyres. This did not cure the problem. I then had the tail
shaft out serviced and rebalanced. It was apparently "out" requiring some
minor work before refitting. This however has not cured the problem. I
replaced the fan which was missing half a blade (hell these things are
expensive to replace!!) thinking this may be the cause. I have also had the
rear axle splines replaced to correct a typical Triumph twitch. But still
the vibration persists. I know that the steering linkages are not A1 and
this is maybe the next step. I have also had the rear wheels checked that
they are "in round" and they appear O.K. I would welcome any suggestions
from members of the digest as to practical next steps to correct the
problem. I was wondering if rear wheel alignment may have anything to do
with causing a vibration such as this. Someone else also suggested that
rear brake drums occasionally can go out of round (and hence cause
vibrations) and if anyone has had any experience or knowledge of this I
would be most interested.

Any suggestions, comments welcome !!

Dean Lewsam
76 Stag 
Sydney, Australia