C3:Front A-arm shims and judging manual

[Steve L.]

The judging manual for a 73 says that the number of shims on the A-arms should be nominally 3 thick ones.

My 73, which I've had since new and has never - ever had anyone touch these shims, has only two on the left side at the front. The back left has 3. the Right side has more than three.

Why does mine have two and the JM says 3??

Steve L.
73 coupe since new

[John H.]

Re: C3:Front A-arm shims and judging manual

Bad assumption in the JG - there was no "nominal" or "standard" shim count; the shim count was whatever it took to stuff the gaps that resulted when the chassis was clamped in the geo-machine, and that gap was a function of dimensional tolerances of many different components.

[Steve L.]

Re: C3:Front A-arm shims and judging manual

John,

You'd think that since the JG has been around for a long time, that this kind of thing would have been fixed.

Steve L.
73 coupe since new

[Joe C.]

Re: C3:Front A-arm shims and judging manual

Steve:

Just an unfortunate choice of words. Maybe a better description would be to replace "normal" with "average". Although the TIM&JG's are good guides, they are not written by technical writers, but, rather, by volunteers. That's one reason why there are always new editions being published!
One more thought about shim count. If you ever see a car with NO shims in any location, then that should send a "red flag" signal. Is the camber/caster setting out of range, or not?

Joe

[Harmon C.]

Re: C3:Front A-arm TI&JM

Joe
Quote The assembly manuals specify a nominal shim pack of 3 shims of.120 thickness. To that a maximum of one .030 and .060 shim may be added. This is a total of .450 or almost 1/2". Un quote The word in the manual is ( nominal)so I think it is OK. The 73's I have had all were less than this number shims. If I see more shim than this I would look for the reason why. Lyle

[Joe C.]

Re: C3:Front A-arm TI&JM

Lyle:

Yes, it is true that too many shims is, OBVIOUSLY a tip off that something is not right. More subtly, though, is that A LACK OF SHIMS might indicate that the setting is beyond adjustability in the opposite direction.

Jos

[Harmon C.]

Re: C3:Front A-arm TI&JM

That is also covered in the TI&JG. I did not put the complete description in my remarks.

Lyle