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>On Wed, 14 Jun 1995 rsmith@jog.syr.servtech.com wrote:
>
>> Could anyone help with problem i am experiencing with excessive
>> toe in on drivers side rear tire. It's a 1973 TR6. Have looked
>> for any visable frame damage or rust. None to be found. Have
>> taken in to a couple of shops in the Syracuse N.Y. area with no
>> luck whatsoever. Will say the Trailing arm does have 5 shims on
>> both the inboard and outboard. Any help would be greatly appreciated.
>>
>> Randy Smith
>
>By excessive toe I imagine you mean a large amount of TOE-IN. From your
>description, I would first suspect that the rear coil spring is tired.
>Since this is the driver's side, this is a very common symptom. Most of
>the TR-6's on the road have this ailment. Since you have a semi-trailing
>arm setup, ride height, toe and camber are all interdependent.
>The next thing I would look at is the frame straightness. The Bentley
>(and possibly the Haynes) manual give frame dimensions that are easy for
>the homebody to check out with a tape measure and plumb bob. At least
>you can tell if the car's in the ballpark.
Normally I'd think you could fix toe-in by removing shims from the
inner trailing-arm mount-point (or adding to the outer). The primary effect
should be on toe, with secondary effects on the other measurements. I would
think that ride-height would have little effect on toe.
Camber would seem to be primarily due to ride-height, though it would
seem to be fairly insensitive (the advantage of semi-trailing arm over
Spit-style swing-axle).
My '70 TR6 has way too much toe-in, which I need to try to fix sometime
soon (.4" on each side). The alignment shop refused to touch the rear
suspension. I may replace the mounts (with the later anti-squat geometry
version) along with the bushings (probably shot) and springs (required if I
change the mounts) first, though.
However, I suspect my frame is tweaked, which might explain the ride-
height differences between sides in the rear (even with new springs). The
DPO hit a curb with the right-front _hard_ (RF rear-lower mount rewelded,
.5" front-rear misalignment of left and right front suspensions, bent upright
(replaced), different castor left/right, and other signs of semi-repaired
damage there.
So how _do_ you measure a frame for misalignment/twist/etc with the
body on the car? Especially twist. The weight of the car causes it to sit
evenly on jackstands regardless of any twist, and I don't have scales. I
suppose if I could support it in one point in front and one in rear I could
measure it, but that's not really feasible. When not jacked up, access is
rather poor, and spring and suspension issues get added to the mix.
Is it expensive to get a frame shop to measure or straighten a frame
(with the body on)? As far as I can tell, I have no significant rust problems
in the frame, though there is some minor surface rust in a few areas that don't
get the british rust-protection treatment (leaking engine/trans/rear...).
--
Randell Jesup, Scala US R&D
Randell.Jesup@scala.com
Ex-Commodore-Amiga Engineer, class of '94
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