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1950 Chevrolet Truck Steering & Suspension Rework
I am refurbishing a 1950 Series 3100 pickup truck for my son who thinks
Chevrolet pickups of that era were " the Cord of trucks." That's fine,
but he also intends to use the vehicle for daily transportation. My son is an
artist, who would be hard-pressed to tell the difference between a spark plug
and a Zerk fitting.
So what would normally have been a straight-forward restoration project
became an effort to make the old truck a little safer, marginally more reliable,
and less maintenance-intensive. This involved some loss of authenticity but, as
I kept telling myself, it's really not a Cord.
I learned several things in the course of the project, the most important of
which was not to trust parts purchased by mail for a daily driver. Some of these
parts are good, OEM quality. Others are suitable only for static display. Nor
should one trust street rodder engineering. I purchased a cross-steering kit
from one vendor with the idea that it would eliminate numerous grease fittings
and update the steering to modern standards. The kit turned out to be nightmare.
Even with exhaust pipe modifications, the steering box probably would have
overheated, at least two universal joints were needed to join the steering
column with the new steering box, and the drag link was not remotely parallel
with the tie rod. That last feature, in my opinion, would have resulted in
severe bump steer. I sent the kit back.
What follows is some notes about the front end, which I am still working on.
Shackles
Early Chevrolet shackles oscillate on threaded bushings, intended to keep the
bodywork in rough alignment with the axles. Other vintage cars used the same
arrangement, which could not have contributed much to stability and, in any
event, quickly wore out.
Modern elastomer bushings give a slightly better ride, eliminate grease
points and should last longer than the OEM style. BRM (937-298-2665) catalogs
shackles for about $60 a pair. Sold separately, their "moly-nylon"
bushings cost $13 an axle set, but you will have to do some fairly serious
modification to get your original shackles to work with them. You could also
turn the bushings from polyurethane (available from plastics suppliers) or
phosphor bronze. Of course, bronze would require some provision for lubrication.
U-Bolts
After 50 years or so, the U-bolts that hold the axle to the springs develop
deep pits at the base of the threads. This is what engineers call stress
corrosion and seamen call " steel rot." Obviously such bolts must be
replaced. A search on the GM computer and a call to Detroit failed to turn up
any. ("1950? That’s before I was born!" ) Suspension shops can
usually fabricate the round U-bolts used at the rear, but the 90 degree bends
used front-axle U-bolts are beyond their capabilities. Finally, a call to BRM
solved the problem.
Springs
At about $200 a pair, new springs seem like a good investment. You can have
the springs made up locally, using the originals as the pattern. The shop may
also be able to order pre-fabricated springs from Dallas Spring or another of
their suppliers.
Spindles
It’s good practice to have the spindles magnifluxed. This inexpensive
process detects microscopic surface cracks that cannot be seen by eye and which
may, over time, result in catastrophic failure. Some auto
parts houses carry undersized spindle nuts that will restore worn
(but not stripped) threads.
Wheel Bearings
Modern cars use roller wheel bearings, which cost less than balls originally
specified by Chevrolet and should last longer. But make sure you get quality
parts. The inner bearing sold by some mail-order houses is non-demountable. That
is, the bearing cannot be separated from its race. This means that the race must
be a slip fit on the spindle to allow the brake drum to be removed without
displacing the grease seal. The race probably does not turn on the spindle,
since there should be less friction between the bearing and race than between
the race and spindle. But it is "half-fast" arrangement that no OEM
would contemplate. Chevy Duty says their bearings are demountable, like the
original Chevrolet design.
Balls
My balls -- the ones on the pitman and steering arms -- have gone flat and I
really don’t know what to do about it. Mail order houses sell replacements for
about $10 a piece, but until these folks furnish Rockwell hardness numbers and
documentation of the heat treat process, I am not going to trust them to supply
parts as critical as these. The last evolution of the Timkin ball was tapered
and threaded for a security nut, which sounds like a good idea. But these
products appear to be extinct as the Essex. Another approach would be to build
up the existing balls with brazing and -- this is hard part -- construct some
sort of cutting tool to restore roundness. Probably the best solution (at least
for pickup trucks) is to use later model steering components which had proper
tie-rod ends. I would appreciate any ideas readers might have.
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