[NeilZ]

There was a great post backed up with facts by 68ragtop back in 2020 That had some great fact based info on caster camber.

I took mine for alignment and the guy said L side couldn't be aligned but didn't really elaborate. Left caster L/R numbers blank, -0.7 camber for both.
Said it might be sitting too low. Guy be4 had Eibach 2" lowering plus he cut
them So I put 2" drop spindles and 1" lowering springs which should
help with mechanical movement. Front end was rebuilt and drum to disk before alignment.

Bad understeer only turning left. Steering wheel doesn't straighten back up
-keeps turning. I got a $20 Chinee bubble alignment tool and was pretty
impressed with quality. Left has -1.75 camber ( 1 back shim), right +0.5.

I am now looking at Global West offset upper control arm shaft which buys +1.5
camber. I have not checked either caster yet.

My 1 question is when moving ONLY your caster by exactly +2 degrees,
how much does camber move and + or - direction ?

The front end was wrecked because after I bought it, I found it has a 70 front
clip not 71. I would like to shoot for pos caster like 68ragtop and stock camber, but don't know if that is possible with the offset shaft. Depends on the camber / caster movement relationship. Thanks for any help

Neil

[JLMounce]

The problem with caster on stock type cross shafts, or anything that uses shims is that it requires negative camber to be added.

To add positive caster to the wheel, a shim must be added to the rear mount of the cross shaft. This also ads a slight amount of negative camber as the control arm is both pulled inward towards the center of the car while also pushing the ball joint towards the back of the car. As you can imagine, to get higher angles of caster, requires more shims. It becomes a balance between what is available for caster while maintaining a preferred negative camber angle.

This is why most quality aftermarket control arms have positive caster built into the arm. You gain caster angle with affecting the camber angle while using shims. You can add or remove caster angle from those arms, through the use of shims as you typically would with factory control arms. In your case, doing offset cross-shafts achieves the same thing.

Based on your measurements of -1.75* of camber and only a single rear shim in place, there is something wrong with that side of the frame or suspension pieces. Possibilities include a bent frame, control arm mounts not in the correct location, lower control arm too long or upper control arm too short. Before spending money on new control arms or cross-shafts, you should determine why the left side will not align as is. Throwing money at new parts without that diagnosis may cause you to spend money and not correct the problem.

Your question about moving caster only, if it's done via a change in control arms or cross shafts, the change to the camber angle will be minimal, to none at all. If caster is changed via shims, it will add an amount of camber, typically equal to half the correlating change in caster.

In regards to your understeer turning left, that's an expected result based on your measurements. You've got very little to no caster (possibly even negative caster) on the outside wheel on a left hand turn. Caster's primary trait is that it adds negative camber gain as steering angle increases. If the caster setting is actually negative, which is possible, you may actually be adding positive camber as you turn, which would reduce your contact patch and cause understeer.

[rjpaige3]

When you get the frame issues straightened out, the trick for adjusting caster independently(mostly) of camber is to transfer a shim from one pack to the other, front to rear or rear to front. You need to plan ahead a bit for this, maybe start with shim packs of one of each size shim 1/32" to 1/4". The steering wheel not returning to center is another giveaway of negative caster.

[NeilZ]

Thanks guys. Jason this was what I was looking for and I kind of assumed caster would go neg. when adding shims for more pos caster,

" If caster is changed via shims, it will add an amount of camber, typically equal to half the correlating change in caster."

What I need to do is check caster first to find out where it stands. If neg within specs, then I might be able to live with ( -1.75 - 1.5 offset shaft = -0.25) a little neg camber. No evidence but I assume the frame is bent. Control arms are stock and I don't plan on changes there.

Well hopefully the right side is ok and I only have to take the left apart again. What's that saying - Third time ...

Thanks again guys. Go ahead and close this one out.

Neil