Theo,
Long ago when I had my Tiger bump steer corrected by the most reputable shop
in San Diego, they simply heated the steering arms cherry red and bent them
in place. I queried the guy doing the job about the need to heat treat the
arm and he told me they were a special air cool alloy and that as long as
you let them cool slowly, they would be fine. (BTW, the improvement was
remarkable.) I have followed the same procedure on many other arms since
then and experienced no problems. The following excerpt is from an article
on air cooled alloys:
"In recent years the through cost benefits of air cooled carbon and
microalloy forging steels have been realized and they have been widely
adopted for engine components such as crankshafts and connecting rods. The
use of air cooled steels in the chassis has occurred more slowly, but
experience has shown that they are suitable for safety critical components
such as suspension arms, steering knuckles and hubs. They are now the
preferred choice of a number of VMs."
Here is the link to the whole article:
http://www.corusengineeringsteels.com/dwn/files/PRODA7.PDF
There is also a posting to the TVR list on adjusting bump steer that
includes how to correctly heat the steering arms. This seems to follow
more-or-less the procedure given in Fred Puhn's book. I would add that the
side of the arm that will be compressed when bent should be at a higher
temperature than the opposite side. This ensures that the arm won't develop
tensile stress cracks. Otherwise the procedure seems pretty good, although
he says the arms should be re-annealed after you are finished bending them.
Follow this advise if you still skeptical that your steering arms are 'air
cooled steel'. Here's that link:
http://www.team.net/html_arc/tvr/199809/msg00010.html
BTW, I completely agree with everything else you say about the futility of
twisting the steering arm to gain clearance and the need to keep the
orientation of the tie rod square (as also noted in the TVR posting).
Bob Palmer
rpalmer@ucsd.edu
robertpalmer@paulhastings.com
rpalmerbob@adelphia.net
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