almcl wrote:
My camber gauge arrived today!
( http://www.motorsport-tools.com/pdf/instructions/GA45.pdf )
I had great fun devising a way to get the front hubs at normal
height with the wheels off but eventually employed a system with
two trolley jacks, one under each spring pan, that got the air hole
in the hub grease covers at the same height as with the wheels on.
Then came drawing out a 40� angle on cardboard and working out
(with a plumb line) where to turn the wheel to.
Flushed with this minor success, I was a bit disappointed to find
the castor(er) angle was less than 2� on both sides. One wheel had
four shims in total, the other had five. I added my sole spare to
the four and transposed one from back to front. This bought the
angle up to a little over two, but nowhere near the required 3.5�.
In fact it appears it needs another 4 or 5 shims a side to get
things to spec (assuming that inserting a shim has a similar effect
to transposing one - unlikely, I know.)
The shims adjustment is principally made by moving the shims from front
to rear, Al, not just adding shims - nominally there is only space for a
specific number of shimd in total, likely the 6 spec’ed - to maintain
the correct angles between the upper whishbone arms and the pivot
shaft…so…?
In extreme cases you may have all shims on one side, but this relates to
another list topic; the different whishbone arms used by Jaguar. This
change was done to allow for increasing castor angles anyway - and
setting increased castor on the ‘other’ type of wishbone may call for
extreme shim moving. Naturally; ex factory they wanted equal shimming
front and back to afford maximum adjustment leeway…
What an ingenious and simple device, I knew of its existence of course,
but prices have come down - couldn’t afford it when I needed it…
Some other remarks; in setting up the tool the wheels should be ensured
fore and aft - any turn of the wheels affects the plumb setting, against
which the castor angle is actually measured, of course.
Now; the plumb line and angles measured with the tool hereafter refers
to ‘horizontal’ ground - and the point of the ride height setting tools
is to bring the car also 'horizontal; ie parallel to the ground. This is
because the castor angle is measured with reference to the car itself,
not to ground - and jacking up the front of the car increases the
‘backward’ angle of the ‘kingbolt’ to the horizontal ground, distorting
the castor angle readings…
An alternative to counter this; with the car on the ground; set the tool
and adjust to ‘horizontal’ - then jack the car up (no wheel rotation)
and record the angle difference. This can then be subtracted from the
castor measurement angles. But both this and during the actual measuring
porces; it’s absolutely essential that the wheels/hubs are not rotated.
Removing the wheels as you did and using jacks for the ‘horizontal’
setting is likely equally good - and in some respects better; setting
hub height with and without road wheel can be done wth some precision…
All this presumes of course that the car’s ride height is otherwise
correct, and you want ultimate precision. But in all this, except for
wheel rotation which directly affects horizontal settings and angle
readings; the deviations are likely fairly small. And as long as one is
reasonable consistent side to side, the errors likely insignificant in
practice…
Frank
xj6 85 Sov Europe (UK/NZ)>This would make 9 or 10 shims. This seems a bit excessive, when
the parts catalogue calls for just 6. Anyone got a figure for the
maximum number that it is sensible to put in? And, before you ask,
no, I can’t see any obvious wear or damage. Ball joints, upper
shaft bushes and so forth are recent and good.
===================================================
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