On Wednesday, June 07, 2000 3:08 AM, thom kuby [SMTP:thomkuby@iwvisp.com]
wrote:
>
> Now the questions are about steering. The car wants to (still) shimmy at
> about 55mph...
IMO, most likely not a steering problem. If the wheels and tires run
straight and true, they won't shimmy unless the steering is _really_ bad
(and I've owned some TR3s that were really bad, but not that bad <g>). If
they don't run true, then the best steering in the world can't force them
to. Things to try :
1) Get the front wheels bubble balanced, with a balancer that holds the
wheel by the lug holes. I know this sounds crazy, but a friend of mine who
has run a tire shop for many years swears by it. And, it fixed the shimmy
problem with my motorhome (which was so bad it wasn't safe to drive).
2) Get the front wheels spin balanced on the car. It's getting tough to
find a shop with this kind of balancer, so call around. Try the local big
truck tire dealer.
3) Try a different pair of tires on the front. Radial tires sometimes
develop defects that cannot be balanced out (stiff spots, soft spots,
sidewall variations, waddle, etc.)
4) With the car supported under the spring pans, try shaking the front
wheels in all directions. Look especially for motion as you push towards
the center of the car on the top of the wheel and pull away from the center
on the bottom. Tie down the steering wheel (so it can't move) and watch
the steering linkage to see where the lost motion is.
> At rest there seems to be an awful lot of slop in the
> steering..like about three inches either way off of dead center.
> 1. does this mean the steering box is toast?
Not necessarily, but possibly. The peg wears the fastest, and isn't too
hard to replace (once the box is out of the car).
> 2. can this slop be adjusted out? (and how do you do that?)
There are two adjustments : bearing end float/pre-load, set by shims under
the front cover; and peg to worm engagement, set by a setscrew in the top
cover. I would suggest removing the box from the car to make adjustments,
although many people do it in the car. The end float is supposed to be set
to zero, which I measured using a dial indicator on the end of the shaft
after finding that doing it "by eye" resulted in .004" end play. The peg
engagement is supposed to be set tight enough to cause a very slight
resistance as the box is turned through center. If you can't get a slight
resistance at center, or it binds at the limits of travel, then the peg,
worm or both are toast.
Note that some slop appears to be normal.
> 3. Is it possible (and feasible) to retrofit a later (TR3B?, TR4?) rack &
> pinion steering rack to this car?
It's possible, but precludes the use of the stock turn signal/horn button
assembly. I believe there's a write-up on how to do it in "More BS on
TRs", which may still be available from TRF. Personally, I think the TR4
steering wheel looks really ugly in a TR3, which is why I've never done
this conversion.
> I set the front-end toe, camber, according to the numbers in the manual
> (I'm using the Bentley repro of the factory pub.).
> 4. Are these numbers correct?
Don't know, but probably. Toe should be just slightly inwards (like around
1/8"), and ISTR camber is supposed to be zero. How did you set the camber
? The factory made no provision that I'm aware of ...
In any case, errors in toe and camber (caster, king pin inclination, etc.)
will not cause (or cure) a shimmy.
> 5. are some other tricks to getting this geometry right?
Not that I'm aware of ...
Randall
59 TR3A TS39781LO - soon to be a daily driver again (Hooray!)
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