I just replaced pretty much the complete suspension (except sway bars) and got an alignment done. After the alignment the car pulls slightly to the left. Not too drastic but enough to be annoying since I have to constantly counter steer.
I took it back to the alignment shop. First they said its because of uneven thread wear. I told them the wheels are practically new so I doubt that. They kept the car for a day and then told me it was because the rear rotor setscrew was stuck between the rotor and the wheel and that caused vibrations and the pull to the left. To put it mildly, that's bulls#%* and here is why: the screws were so worn out I had to drill them out and remove them. I figured the wheel and wheel nuts will hold the rotor in place just like in the fron.t There are no setscrews in there that could get stuck. I told the mechanic that in a diplomatic way and he then said it must be my frame is bent....wtf? All they did all day long is switch the tires from the front to the back which should eliminate the tread wear issue but it didn't. When I got there to pick up the car the janitor gave me my key, no one was there to answer any questions. I gave up on the place and now I'm trying to figure out how to tweak it myself.
Here are the values from the alignment sheet they gave me:
Camber
Left Front -0.5
Right Front -0.6
(supposed to be -0.16 +/- 0.5 so its ok)
Left rear -0.9
Right Rear -0.7
(supposed to be -0.9 +/-0.25 for sport or -0.67 +/-0.25 for comfort. so I got sport on the left and comfort on the right lol)

Caster
Left Front 3.0
Right Front 2.5
(supposed to be 4 +/-1 so borderline ok)

Toe
Left Front 0.08
Right Front 0.07
(supposed to be 0.15 +/-0.05 so its too low on both sides)
Left rear 0.12
Right Rear 0.15
(supposed to be 0.15 +/-0.05 so both ok)

Steer ahead 0.01 (not even sure what that is, explanation welcome)
Thrust angle -0.02 (same here, explanation welcome)
All values compared to the ones stated in the Haynes manual.
What could make it pull to the left?

 

When you say complete suspension replaced, what do you mean? I assume struts/shocks.

I don't have a feel for how critical the toe is on these cars.

Two possibilities come to mind. 1) the spring may not be seated properly on a front strut. 2) the alignment machine is not calibrated properly (yes, I had this happen).
Stan

 

Here is what I replaced:
Front:
complete strut from strut all the way up to strut mount and sway bar endlinks all phase 2.
Lower control arms including bushings and ball joint
Outer tie rod ends

Rear:
Also complete strut from strut all the way up to mount.
Trailing arm bushing
Inner and outer bushing on the lower control arm
both upper control arms
Sway bar endlinks

The only thing I didn't do is sway bar bushings, front because they are a bitch and rear because I forgot to order them

I read a lot about how critical the correct alignment of the strut to the mount is and how critical the seating of the spring is so I tried to be extra careful. Not saying that I don't make mistakes but I know I wasn't careless.

I did some experiments tonight:
Switched the front wheels left to right and right to left. They are directional thread so I won't leave it but to test it was ok. It still pulls to the left but not as much as before. Switched them back after test drive.
Switched the rear wheels left to right and right to left. No difference. I'll switch them back tomorrow and then I'll try switching front and back.

Seems like I do have some uneven thread-wear but it also seems that the alignment is still off.
Also: The steering wheel is not straight.

 

It could be a bad alignment. I had mine to NTB in Beltsville, MD 3 times to get the alignment right and tire balance right. They showed me the numbers and they looked good all 3 times on two different alignment racks.

The 4th time I want to Merchants in Columbia (same company so no extra cost). Sure enough, the alignment was out and the tires not properly balanced. It was fine after that. NTB apparently had just had their racks calibrated but, apparently it was a bad calibration.

Stan

 

I had a similar experience after getting new tires. First alignment was off, took it back to a different shop of the same franchise and they said oh you were off - maybe the other machine wasn't calibrated. Better but still not right. Took the car to a dealer and they said "oh car was close but slightly off spec" and got the car spot on. Side comment was that the S40 is sensitive even within spec so a dealer with experience will tune to one end of the spec vs just "in spec"

 

The guy at Merchants seemed to know that these cars are sensitive to alignment and balance and was very meticulous about dialing it in. Unfortunately, I think he left.
Stan

 

I guess I'll be heading back for another alignment. I don't think I'll go back to the place that did the first one though. Its a single repair shop, not a chain so I'll have to pay again but they only had one alignment machine and a lot of excuses why it is my fault the alignment is off.
Kinda sucks because that's the alignment place that the Volvo repair shop I trust recommended.
I'll update once I got it aligned again.