How much you have to take apart on the trunnion depends on what
the trouble is. The usual failure on a Spitfire/GT-6 trunnion is
the Delrin (or some such plastic) bushings where the lower control
arm itself attaches to the trunnion. The bushings fit into holes
in the trunnion, and into the bushing go metal inserts, and into
them goes a bolt running longitudinal to the car. These bushings
are the pivot for the lower control arm w.r.t. the trunnion, and
when they collapse, you get lots of slop in that joint. This
results in poor camber control and poor toe-in control, since
the lower portion of the vertical link can now swing in and out.
The bushings can be fixed easily just by jacking the car enough
to take the weight off the tire (oops, sorry, I meann tyre). The
lower control arm and the spring are held by the shock-damper so
there are no forces on the trunnin when the tyre is lifted.
On the other hand, if the trouble is the threaded joint where the
trunnion attaches to the vertical link, you have to take the brake
disk and stuff off simply because the trunnion won`t rotate to
let you unthread it with the brake stuff in the way. If you've
been lub'ing it regularly, that threaded joint should not be a
problem, I would think, and anyway, I don't see any easy way the
MOT guy could have discovered a problem there unless he took it
apart there too! Look to see what the trouble really is, and
chances are you just ned to do the bushings. That`s easy.
Jim Muller
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