Dear Ulix, Frank, Adrian, Larry, and Spridgeteers,
Thanks for the replies on steering column bush replacement. Several of you
asked to be kept up on my progress. I found that the bushes were in pretty
good shape. The bottom bush is in a brass (?) clip and it had worked its
way out of the tube. Both bushes looked to be in great shape, though. I
re-assembled the column leaving the old bushes in. There was some slop, so
I pulled the column (it's really easy once the draught excluder is removed)
and replaced the top bush (Haynes says that this is the one that will allow
slop when old). Simply putting the bottom bush and brass clip back in place
got rid of the bouncy steering wheel. Replacing the top bush got rid of
most of the remaining play. I found that top bush replacement did not
require removal of the steering wheel. The old bush came out by poking a
punch into the side of the old bush that was exposed by an oblong hole in
the outer tube that BMC engineers thoughtfully placed there. I just pushed
the impaling punch towards the steering wheel and the bush slowly came out.
I started the new one by slipping the pointy corner into the space between
the inner and outer tube, then I twisted the outer halfway down onto the
bush, then back twisted it to align the egdes of the bush, then pushed the
last way in with the lip of a 9/16 open end wrench. A screw driver tip
seemed too sharp. Everything works and is fairly tight. Thanks for all your
help. But some thoughts about safety:
The cinch-down bolt is just an accident waiting to happen. First, the
manual _specifies_ that the bolt be head down when the steering wheel is in
the straight ahead position. In aircraft work, bolts are always head up so
that if a nut works loose, the bolt is at least held in by gravity. When is
the nut most likely to loosen? When you're making a long trip with constant
vibration. With the bolt head down while you're driving stright ahead, this
greatly increases the probablilty that the bolt will depart as soon as the
nut departs! But far worse than this is the various stresses applied to the
bolt. A bolt and nut should be a tension solution. This is the case here in
that the bolt and nut compress the split collar at the end of the steering
column onto the splined pinion stub. The stub diameter is oversized with a
groove in its perpendicular axis. The theory (according to Ulix, and I
agree) is the that the bolt shaft rides in the groove so that even if the
nut loosens, the steering column remains engaged to the splined pinion stub
as long as the bolt rides in the groove. But think about this. Everytime
you hit a bump, you pull on the wheel, which transmits sheer directly to
that bolt due to this arrangement. Everytime you have to slam on your
brakes, the whole momemtum of your upper body is checked by your pushing
on the steering wheel, which transmits sheer directly to that bolt also.
Bolts are designed for tension, not sheer.
I'm sure that a lot of this is half-baked, but for me, the bottom line is:
use the best quality bolt you can find for this application, and
periodically (like once a week) make sure that the locking nut (nyloc or
split) is still doing its job. (BTW, would it be bad to smear the threads
with loctite or somesuch to additionaly ensure that the nut does not
loosen?).
Jeff
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Jeff Boatright __o_\__ '65 A-H Sprite
http://userwww.service.emory.edu/~jboatri/sprite/sprite.html
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