re: 115 GTV rear bushings

[Dana Loomis <dloomis@domain.elided>]

>The back of the '74 GTV is getting loose these days (tail wag in S
>turns), so it's time for some new bushings back there.  I was wondering
>what opionions people had about this job:
>1 -- Which bushings are most likely to be in bad shape (I plan to do all
>of them, but might skip a few if they were tough to do and unlikely to
>be toasted)?

This kind of handling problem can be the result of excessive clearance
between the cast torque T and its carriers that are bolted to the car body.
 There are supposed to be thick rubber washers in the gap between the T-bar
and the carrier, but in many older 105/115 cars these washers are missing
or seriously deteriorated.  This can allow the rear axle to move laterally
as much as 1/4 in, producing rear-wheel steering.  This problem may be more
common than really deteriorated rubber bushings at the suspension mounting
points and can cause pretty dramatic oversteer when you want it least.  

If you go to the trouble of replacing rear suspension bushings, I'd
recommend using polyurethane wherever they're available.

>2 -- How much work are they?
>3 -- Which ones require special tools or excessive forces?

Removing all the relevant parts from the car should take less than an hour
and is an easy job with standard tools.  To change the "trunnion" bushing
(torque T to differential mount), you need to support the car (not the rear
axle) on stands so the axle hangs in the limit straps, then remove the
wheels, unbolt the T-bar and sway (anti-roll) bar and disconnect the shocks
at the lower ends.  Now you need to disconnect the trailing arms from the
axle: working on one side at a time, put a jack under the rear end of the
trailing arm right under the axle, unbolt the trailing arm at the rear end
and lower the jack to slowly relieve the compression on the spring,
allowing the trailing arm to hang from its front mounting point.  To remove
the trunnion bushing, push the axle to the right to disengage the pin on
the differential case from the T-bar.  Replacing the bushing is a simple
matter of pulling the old one off and re-assembling the whole thing in the
right order.  

While you're doing the trunnion bushing, it's easy to remove the trailing
arms altogether so those bushings can be replaced.  All you have to do is
unbolt the front end of the arm from the car.  I'd advise taking the arms
to your Alfa mechanic to have the old bushings pressed out and new ones
pressed in.  Polyurethane bushings generally don't need to be pressed in,
so you can skip that step if you're using them.  Some poly replacement
bushings are actually made to fit inside the metal jacket of the original
rubber and steel bushing.  if you're using this kind, you can change them
at home without a press by burning out the rubber part of the old bushing
with a torch and cleaning up the bore with emery paper.  

Dana Loomis
71 1750 GTV
72 2000 GTV

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