Caster Issues

[Dano 1]

I recently went through and rebuilt the front suspension on my 69. Initially I went with poly upper control arm bushings but after checking the alignment and finding 0 caster on either side I swapped out to the moog offset bushings in an effort to increase caster.

I finally got around to re-aligning the car and found the passenger side to have a decent +2.5deg but the driver's side is only sitting at +0.5deg, essentially unchanged. I have checked the orientation of the bushings and everything is good so what gives? Is this just a factory tolerance stackup issue or could something else be going on?

I measured the strut rods as best I could in the car and they both appear to be the same length, all the other parts are reconditioned stock units with stock replacement rubber bushings. Are there any other measurements I could check to confirm if I have other issues?

I'm not opposed to aftermarket upper arms but I don't want to drop $400+ if there's something else wrong with my system that would negate the benefits of even an aftermarket arm.

[b5blue]

Check the strut bushings. (I used solid mount adjustable on my 70.)

[Dano 1]

Strut bushings are new rubber on both sides, nuts torqued to spec. What typically goes wrong during assembly etc. that would cause an issue?

I looked at adjustable strut rods as well but I don't want to introduce any binding into the lower control arm bushing trying to get the caster fixed. It's a rubber bushing but it still feels like a bit of a crutch to use the strut rod to pull things back into alignment.

[cdr]

just get some adjustable upper arms, that what I did.

[Kern Dog]

If the driver side ever hit a curb with any force, it will reduce caster. Maybe the K member is bent, maybe the control arm has a slight bend.
I hope that you requested some negative camber.
The lower the front end, the easier it is to get the camber in the negative range and the positive caster is more easy to achieve there as well.

[Dano 1]

You're probably right KD, I guess I was hoping to be able to narrow it down to figure out the best way to fix it, strut rods/upper arms etc. It doesn't seem like there's a lot of info out there with dimensions to check or data on where things should be to help narrow it down. If the lower arm/mount is bent and it can be fixed with adjustable strut rods, great. If it's the upper mounts then trying to fix it with strut rods won't be the right move and adding upper control arms may or may not fix it. I'd rather just determine the exact problem before starting trying to fix it.

[HPP]

Obviously any deviation from the originally squared and equal set up has been adjusted to make it drivable. You can continue down this path or correct the root cause.

Any number of issues can create inconsistent caster form side to side. You can either tear into everything from k-frame location and dimension to individual component inspection to find the core issue and correct. Or you can pick up adjustable uppers and dial them into to where you want and not worry about anything else.

Either approach will achieve your goal.