Hi Jack,
Technically, you should replace the fulcrums to help the new bushings last as
long as possible and be sure play in the joint is minimized. The wear on the
pins is due to dirt and water splashing up there and working it's way inside
old, worn bushings. The more worn out the old bushings become, the more easily
grit gets in there and chews things up. Once the pins are roughed up, they
will tear up new bushings. As already noted, rubber bushings would be more
vulnerable than urethane. You might be able to get by for a while with
urethane.
Whether to replace the fulcrums or not depends on how bad condition the pins
are
in, and how much you relish doing the job again in a year or two or three or
five, depending upon how bad the pins are plus how much and how hard you drive
the car.
Alternatively, it might be possible to sleeve the damaged fulcrum pins. I
noticed on a recent rebuild that the lower, inner sleeves are the same
diameter,
although a bit long. Simply cutting the length down a little on these would
make a sleeve to fit. If you do this, leave the sleeve just slightly longer
than
the pin area, protruding 1/32" or less into the threaded area, so that the
washer will clamp down on it and lock it in place once the nut and washer are
put back on. Also, these sleeves are available in stainless steel, a lot less
prone to rust problems in these vulnerable joints.
If sleeved, the urethane bushings will be too small diameter inside. They can
be enlarged a little with a small drum sander or similar on a drill or other
rotary tool. Just use a slow rpm, keeping friction heat low, to avoid melting
the urethane. Alternatively, the nylatron (white nylon) bushings used on the
lower, inner joints could also be used. Both inside and outside diameters are
correct, but length again would need a little trimming. With these, the white
nylon thrust bushings would also be needed. However, be warned that nylatron
bushings in the upper joint will be noisier and transfer more "road" to the
suspension, just as urethane will be a little less forgiving than the original
rubber bushings. On the other hand, urehane will be more precise than rubber
and
nylatron more precise than urethane. But, also, any slight misalignment of
suspension will be more obvious with harder bushings.
On a related note, I suggest using a little synthetic grease on the inside
those urethane bushings. This helps prevent "urethane squeek". A grease with
some Teflon content is ideal. I usually use "Finish Line" grease, found in
small
tubes at some bicycle repair shops. It's waterproof, won't thicken or thin.
Cheers!
Alan Myers
San Jose, Calif.
AMfoto1@aol.com
http://hometown.aol.com/amfoto1/amfoto1.htm
I'm in the process of doing a complete front end rebuild on the TR3A and the
upper fulcrum is a little chewed up, not outlandishly so but it's not
machined and smooth. Kind of pitted and probably slightly out of round.
Rubbers
were still there so it had to be a DPO. The bushings fit over it so I'm
wondering if I should replace the fulcrum or will the urethane bushings make
up
for the irregularities?
Thanks in advance,
Jack McMahon
TR3A S56298L
Philadelphia, PA
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