vague steering

["Mark Battley" <m.battley@domain.elided>]

There is another possible cause of vague steering for the 105/115 cars:

It is relatively common for the big nut holding the steering arm on the
output shaft of the steering box to come loose. The arm is located by a
tapered spline. If the nut is left loose for a while the spline wears (I'm
not sure how much of the wear occurs on the shaft and how much on the arm,
although I would have expected the shaft to be harder), which can mean that
even when the nut is retightened the arm may still be loose. 

What happens is that the arm slides far enough up the arm that the nut
"bottoms out" on the end of the splines before the arm is tight on the
splines. It's easy to check: reach under the car, put a finger in such a
position that it touches the nut and the arm at the same time, and get
someone to wiggle the steering wheel. You will feel any relative movement.

Possible cures include the obvious (replacement of the arm and/or box), or
more simply and cheaply putting an appropriate washer under the nut that
clears the end of the splines, or machining a rebate in the back of the nut
(I replaced mine with a Nylock).

The "finger" test is the best way to check the steering ball joints, idler
and steering box bushes. The wishbone bushes and upper and lower balljoints
are harder to assess in the car. With the suspension unloaded the balljoints
are under a lot of tension. To check the lowers (which tend to have a
shorter life than the uppers) you can jack under the wishbone to unload the
joint, then lever the upper arm upwards with a finger on the joint. I will
say though that even with seriously shot lower balljoints and wishbone
bushes mine did not feel particularly vague. It's better with new bushes etc
throughout, but it didn't feel unsafe as it was. It did feel vague with a
loose steering arm though! 

There are a lot more possible sources of slop in the steering system than a
rack and pinion system, but the steering should not feel vague and unsafe.
If the front end seems okay, check the rear suspension trunnion and trailing
arm bushes.

Mark Battley
Auckland, New Zealand.

1973 Alfa Romeo 2000 GT Veloce

Alfa Romeo 105 series Bertone Coupe home page and register at:
      http://www.geocities.com/MotorCity/1806/105GTV.HTML

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