Caster issues

[Pat D]

I have a 78 SC. I've attempted to get a wheel alignment 2x unsuccessfully. The right wheel is centered in the wheel well, but the left side wheel is to the rear of the wheel well and off center by 1". The last tech suggested his opinion is a few possible issues. Right side Caster=+.09. Left side Caster =-.21
1. Possible that the car has been hit. It understand that's a possibility, however on inspections it doesn't appear to be any damage and taking multiple measurements, it appears that everything's is square and in its proper place.
2. 45 year old suspension is simply tired and need to be updated. The adjustments for ride height in the front are not even close in appearance and exposed threads, however the right height is level.
3. Left side strut could be bent or broken. No obvious damage, tho.
4. Install the aftermarket strut adjustment to gain more adjustability.

I've tried to attach an image of the alignment specs, but its not working. I can see this is a process of elimination, but I'd love some guidance on where to start. Is this common? I don't want to just start replacing parts without good reason. Thanks for your help.

[r lane]

1'' is a lot anywhere. You have measured base on both sides. Chassis gauges will tell you whether it is square or a trap. You can get equal measurements and not be square.

[stownsen914]

Agree with r lane. Keep in mind that bodywork can be off as well, as a consequence of being an older, hand crafted car. It’s not uncommon for bodywork on a 911 to not be square, though 1” is admittedly a lot. Try measuring to something other than the fender to see if that 1” is real.

Consider that suspension pieces could be damaged, worn out, mismatched, or assembled improperly, causing them to be out of spec.

[PeteKz]

I had similar problem last year, but my wheel wasn't back an inch. I could not get the right caster into spec. In my case, the right strut tube was bent, probably from a big pothole or curb impact before I owned it.