> From: N7559R@aol.com
> Subject: <GT6> Help with GT-6 BAD vibrations!!?
>
> Hi all,
>
> Drove my GT 6 Mk 2 for the first time in a long time today!! One and a half
> years in storage (DRY and WARM) Put in a new battery, turn the key.....
> NOTHING. Well not a big surprise anyway. Warning lights all came on with
> the Ignition so, Tap on the starter relay, ZOOM starts right up and
> runs good, amazing!
>
> Put new fluids in all around oil, gearbox, water, clutch master cylinder,
> brake master etc.... Go for ride... Lots of vibrations. On power, off
> power, and during float.
>
> The drive shaft has two new universals so I don't think it is the culprit.
> The car has wire wheels so I begin checking hubs and I find they have rust
> on the splines, YUCK!! Only the rear hubs appear bad. Questions: 1) Can
> the rear wire wheel hubs cause this? 2) Is it likely that the rear bearings
> (wheel) are causing the problem ? 3) What is the best way to check the rear
> wheel bearings? (These are the ones that are miserable to remove ???) 4)
Jeff, you mentioned that the driveshaft U joints are new. Was
the vibration there before you replaced them? There are two more
U joints where the axle shafts attach to the diff. These could
also be bad. Try unbolting these so that the driveshaft turns
the diff, but the diff does not turn the axles. If the vibration
is still there, it's the driveshaft. Check to be sure that the
new U joints are installed correctly. If in doubt, take the
driveshaft to a shop that specializes in driveshafts and have
them balance it. It could also be a bad bearing in the rear of
the gearbox or in the front of the diff, but a bad pinion
bearing would probably first show up as a howling diff. I chased
a vibration in my GT6 for years and finally discovered that it
was a bad bearing on the output shaft of the overdrive unit.
I had taken the bearing out before and it seemed fine but when
I replaced it, the vibration went away. Also, the GT6 Plus
has Rotoflex joints on the outer end of the axles. I don't
have any experience with these, but I assume that they could
cause a vibration in the axles if they begin to fail. Bad
axle bearings would show up as noise more than vibration I
think.
Others have mentioned flat spots on the tires, this is a good
possibility. Try jacking up the rear, putting it on stands,
and running it with the rear wheels off the ground. It might
be a good idea to do this outdoors so you don't drive through
the garage wall if it falls off the stands. See if either
of the rear wheels seems to be wobbling. Now try it with
the rear wheels removed from the car. Still there? Back
to the axles and driveshaft again.
Did the two driveshaft sections get taken apart when the
U joints were replaced? If so, they might not be aligned
correctly. A driveshaft shop can determine this. If it
sounds like I have been through this before, I have.
Dave
1967 GT6
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