Thanks CKVortec. Much appreciated. Yeah, I sometimes tend to write a lot to get all the details out there. There are not supposed to be any "loose" bits in my steering linkage. I specifically asked my guy to look for that at my safety "pre-inspection" so I could change anything that showed any visible wear. That said, I fully expect worn rubber bushings to some degree. The tires are new, 50 psi front & 80 psi rear, rear airbags both at 0 for the alignment. I would be shocked if anything was bent given the history of the truck - babied by the original owner and me.
So, I take it you're saying the 0.0-1.0 degree camber spec is Positive and correct? They didn't just forget the " - "? If so, I guess your favoring the camber by about 0.2 degrees higher on the left would look something like +0.2 left and 0.0 on the right? Considering that, and considering that not all my roads are crowned the same - or even the same way - I think I should ask for 0.0 camber on both sides.
I understand what you are saying about the caster. My factory set caster seems to be 2.3 degrees left and 2.2 right. I'm sure they were gunning for even and that is what the knockouts gave them. Given that, I think I should aim for 2.3 left and 2.5-2.8 on the right.
So, with the historical 0.5L, 0.1R camber and 2.3L, 2.2R caster it always pulled a bit to the right - couldn't let go the wheel for more than a couple of seconds.
What do you think of my plan?
Thank you,
Glenn
I would say your plan sounds solid, just because GM decided that 0.0 to 1.0 degrees was what they should have for a spec doesn't mean you HAVE to set it at positive .5 right in the middle of the range. Just that for some reason the way the short arm/long arm suspension works when hitting bumps or cornering and such influenced their recommendation.
Going with a negative will also work, but due to the heavy truck bodies and body roll in corners and such it might not be the best choice.
I don't have any empirical data for you, just my experience that 1 degree positive or negative doesn't seem to make a whole lot of difference as long as both sides are a close match.
If you are going to ask for camber to match on both sides you may need to increase the cross caster a bit to compensate for road crown or "drift".
Also, being able to let go of the steering wheel for a couple of seconds is not bad to start with, I classify that as a "drift" rather than a "pull" and could easily be caused by road crown or cross wind conditions, so find yourself the best piece of road you can and drive it on a calm day in BOTH directions and make sure before condemning the hack at the alignment shop.
As I stated before, you could also have a tire condition causing this, so if your alignment numbers don't reveal the reason for a pull make sure it isn't the tires by doing a side to side rotation (check tire pressures as well, 5 psi will make a big difference sometimes).
If the truck still drifts or pulls it will be really hard to nail down the cause, but some things I have seen in the past are:
rear drum brake adjusted improperly
one front disc brake dragging slightly more than it should
control arm bushings replaced on one side weren't tightened down at ride height
driver weighed 450#
rear spring replaced and tightened down while drooping, not at ride height.
power steering box applying some pressure/force one direction.
good luck, and remember, it's still a truck so it'll never drive like a caddy.