Spridgeteers,
As you may recall, I noted a small difference in the ride after hitting an
impressive pothole with the right front tire. This prompted me to explore
my Sprite's front suspension. Thanks to the several listers and Lamar at
AIAP (URL below) for input on this. The Gillspeed inspection profile from
the AHSDC's monthly magazine (Goblins' Gazette; URL below) was useful also.
For the enlightenment of others, here's what I found so far.
The car had been well-maintained before I bought it. I continued the
tradition and applied the grease gun to the nipples at least once a month
and more often if the car had gotten a good run in the rain. Possibly due
to this, all parts disengaged from one another easily. How long has it
been since you greased your nipples? Pardner, that's too long! BTW, from my
VW days, I learned that you don't just apply a few strokes. You apply and
apply until the goo that comes out is as clean as goo that's going in.
I found that the damper arm wobbles on its shaft. I've studied the front
suspension drawings and the front suspension on the car, and I can't
understand why BMC thought that using damper arm double-duty was a good
design in a sports car. Wasn't there someone on the list who fabricated a
triangulation fix? I think he welded a rod with a ball joint onto the
damper arm at one end and onto the suspension tower (box) at the other end.
If you have this URL, please email it to me. Additionally, one of the
damper set bolts (holds the damper to the car) was stripped and was
providing no compression. This was replaced and torqued to 25 lb ft.
A bit of advice here - when tapping out the upper fulcrum pin (the pin that
runs through the trunnion and outer damper arm collar), do not let the
trunnion turn on the kin pin shaft. If it turns and you keep tapping,
you'll damage the fulcrum pin threads because the pin will be hitting the
damper collar walls at an angle as it passes through the collar. To prevent
this, tap on the pin until the hex head at its other end is clear of the
metalastick bush, then pry the pin out using an open-end wrench pressing
between the pin hex head and the washer on the end of the bush. I.e., make
sure the fulcrum pin is removed straight out while keeping the trunnion and
damper collar together and in line with one another.
The lower outer wishbone fulcrum pin may to have some play, but not much.
Unless I'm misunderstanding the geometry, this seems to be an important and
non-redundant item. That is, once this goes, won't the wheel fold under or
out? Youch. I'm a little confused as there does not appear to be any type
of bushing. Does the lower king pin collar simply ride on the lower fulcrum
pin, metal to metal? And if so, does the king pin collar wear as much as
the fulcrum pin? I ask this because the fix for wear here seems to be
replacment of the fulcrum pin, but none of the manuals talks about
replacing king pin due to wear here, or of there being any bushes.
The right side also has king pin end float. To correct, you are supposed to
remove the kin pin shims from under the trunion, then re-tighten the
trunnion retaining nut. Again, the persistant greasing came in handy,
because apparently the trunnion and swivel axle often become rusted
together. I found that there were two shims left, one of which was pretty
trashed. I removed both, and voila, no more float, but still free movement.
Once I corrected this, almost all, if not all, movement was taken up except
for that allowed by the wobbly shock arm and the lower outer wishbone
fulcrum pin. I do not see wear motion in the king pin bushes themselves. I
was pleasantly surprised.
The left side has almost no movement at all on anything.
Jeff
AIAP: <http://www.atlbritishautoparts.com/>
Inspection profile:
<http://yallara.cs.rmit.edu.au/~mg/cars/goblins/tech/frontend.htm>
Jeffrey H. Boatright, PhD
Senior Editor, Molecular Vision
http://www.molvis.org/molvis
"Seeing the Future in a Very Tiny Way"
|