Help! I just got my alignment done (went back to stock springs - see sig) and the "cross caster" is not within spec. Individually, they are within spec. Is it possible then that one side of my car was sitting lower than the other?
Caster readings are:
Front Left
7.6 degrees (7.4 to 8.9 range)
Front Right
8.5 degrees (7.4 to 8.9 range)
Cross Caster
-0.9 degrees (-0.8 to 0.8 range)

It also feels like if I center the steering wheel, it turns very slightly to the right. The alignment guy said I might have hit something, but it won't affect anything because he did the alignment. I haven't hit anything, and I believe it will affect handling because of the uneveness. Perhaps I will be able to hold turns one way significantly better than the other. Please help.

 

significant caster spread can cause car to want to go one way...I like to see a .3-.5 degree spread....keeps car straight on most roads in my area.

Answer me this:
Is the wheel being slightly pulled to make it go right? or is the wheel centered, and the car goes right?

I'm willing to bet he didn't get the wheel quite centered during the toe setting...lots of "alignment guys" are lazy/incompetent....when you break the lock nuts loose you can move the steering wheel...so it should be recentered after breaking them loose. and again after tightening everything down....this is the difference between an **** alignment guy, and a slacker.


Regarding the caster spread. Did he check the SAI/Included angle? He should have...just because on an non-adjustable car, this high caster spread screams "somethings wrong". SAI/Incl. angle tells you if something is bent.

Did u buy car new? used?


Also, check tire pressures....HE SHOULD have checked them all before the alingment....and made sure they were all equal...uneven pressures can do all sorts of things.

 

Thanks Texas. I re-checked the tire pressures and set them at 35psi. I bought her new, and this is the second alignment I've done - the first was when I installed the SWIFT springs, but now I'm stock again.

I took her back in and whadya know, the alignment guy had to fix the alignment both in front and rear all over again. But now the printout says my SAI is indicating left front damage. Seriously, I don't remember hitting anything on the road that could have caused anything to bend. They want 1 hour of labor to inspect the suspension to find out what is bent.
Before I take it in, should I just look at the steering knuckle to see if I damaged it while installing (even tho I don't see how because it wasn't touched)? According to this link, it says it is most likely that.
http://www.familycar.com/alignment.htm#Cas

 

Honestly the alterations (bends) in the knuckle often cannot be seen. It is the most likely place for a bend because of its long and thin upper half. other prime possibility is the LCA. but knuckle is it 90% of the time. It also could be subframe damage....but this isn't terribly likely. The shop is going to look for obvious signs...which are hard to see w/ cast alum. parts...then they will say the same as above...most likely knuckle.

What did your alignment come out to this time? They should have realigned for free IMO....tire pressure is first step...I'm disappointed in that shop already.

Typically you won't see bad SAI/Included angles unless the car has been in a WRECK. or slammed into a curb sideways...pot holes etc shouldn't cause this unless you have a bad part IMHO...suspensions are designed to take pot holes when going straight....its when you hit those pot holes while sliding sideways that becomes an issue.

 

Yeah they re-aligned for free. Now it drives much straighter. Here are the readings.


Front Left Caster & Camber
7.7 (7.4 to 8.9 range) & -0.9 (-1.3 to 0.2)
Front Left SAI & Included Angle
2.7 (4.3 to 5.8) & 1.8 (3.0 to 6.0)
-------------------
Front Right
8.2 (7.4 to 8.9 range) & -1.2 (-1.3 to 0.2)
Front Right SAI & Included Angle
6.7 (4.3 to 5.8) & 5.6 (3.0 to 6.0)
-------------------
Cross Caster & Cross Camber
-0.5 (-0.8 to 0.8 range) & 0.2 (-0.8 to 0.8)

 

If it drives like a charm I wouldn't bother trying to hunt down the possibly bent part....(Since I haven't torn a Z's suspension completely apart this could be a bit off) But given that one side is high, other is low (SAI/Incl) its highly possibly that the subframe is shifted to one side or the other. I've been able in the past to loosen the subframe bolts and shift the subframe back to the other side....again since I haven't done this on a Z, I cannot say for sure it'd work...due to design differences in frames/suspensions its possible that it wouldn't.

If it doesn't have a low speed pull I wouldn't bother with it...personally.

 

Thanks Texas. I'll put her up on jack stands this week and check out the steering knuckles for any visible difference left to right.
She does drive like a charm now though (except for some noises from the front suspension when turning or hitting bumps). Very straight line, steering position is straight the way I like it, and tossing her through some left-right-left-right mini slaloms feels good. If I have any questions after I inspect, I'll post up again.