Finally got the front end checked and had the toe in set. In the process I found the RF castor is a negative 1.4 degrees. The bushings on the control arms don’t have significant wear and don’t appear to be bad. To fix this it appears I need to shim the upper ball joint. Is that correct? How many shims and what side of the ball joint do I need to move it degrees to match the LF reading of 3.2 degrees positive?
I would say more likely the lower control arm fulcrum shaft is bent.
That would be consistent with other things that Ive recognized. Salvage Title, frame broken forward of the suspension, broken lower "spoiler/bumper and a spacer in the spring. My question would be why the lower control arm?
According to the manual, by moving a Castor shim (1.6mm) from one side to the other you alter Castor by 0.25°.
So even if you move all four you gain only 1°.
Something is seriously bend…
Because it’s the one that takes the majority of the force on an impact, and the fulcrum is the weakest point.
But it could also be that the frame itself is bent, or both.
Either that or the measurements were taken incorrectly. Like, if the locking tools were not used…
If this proves to be the case, would you guys recommend he just go get another subframe from a junkyard?
This is indeed a possibility, but 4.6° is a lot.
Which I bet they weren’t.
This would greatly affect Camber though but not so much Castor i.e. King Pin Inclination.
After an accident the subframe can be distorted in ways that cannot be revealed while mounted to the car. A bare bones subframe only weighs about 27kg and not what I would call a sturdy structural thing, and only stiffens up when the control arms and the like are bolted to it. If the subframe is out of spec, there will be no way to achieve proper alignment. In the ROM there are dimensional specs that will allow you to verify the accuracy of the lower control arms as a starting point.
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Thanks for all the great information. The RF subframe mount bushing is damaged and is probably the cause of my situation. I found a local alignment shop whose owner owns a couple of jags so Im headed there this week.