I have recently bought an o4 car that has had a passenger side rear accident. (This is a right hand drive car). It has been on a laser jig and straightened. The accident pushed the wheel forward breaking the lower arm, the link stabiliser and twisting the upper arm. These have all been replaced and the wheel alignment done. Under heavy acceleration the car pulls to the right, if you take your foot off the gas it then pulls to the left. In a straight line doing 70 in 6th if you press the gas and let go of the wheel the car changers lanes to the right. The tyre pressure is correct. Have you any ideas?

 

This would have been my first guess. Double check again?
How is the condition and tread depth of each rear tire? You don't have a newer one on one side, do you? Not a mixed (brand and age) of tires?
It may also be a case of the straightening not having gone as well as they may have told you. Same goes for the alignment. They may have done the best they could and just told you it was to spec.

 

I'd like to see the printout from the laser alignment jig and the printout from the alignment machine.

My car pulled/pushed under power like you describe, though not as badly as you describe, when I bought it with non OEM tires, so that's another possibility.

Since the most common cause of this kind of problem is tire pressures I'd check that again even if I were certain the pressures were correct. I'm with XV and think this could well be a tire issue, but short of confirming that the frame is straight and the alignment is correct there is no way to be sure what kinds of issues the car might have.

 

With both the above.

BTW get yourself to the UK forum!

https://www.s2ki.com/forums/index.php?showforum=25

 

one of 2 things if not tire pressure:

have another alignment done, something is not set correctly/installed correctly/bend

another thing is to check the tire with the other side. is it at the same spot in the wheel well, or is it pushed forwards/backwards/in/out? if so, the attachment points of the suspension parts are messed up.

 

You have new arms on one side and old arms on the other, so could the bushings be more worn on the old side enough to have more play on that side under acceleration and deceleration? The alignment seems to be okay when maintaining a constant speed when there is less stress on the joints.

 

What was the thrust angle setting when you had it aligned? 0.00? Were you in the car while it was being aligned?

http://www.tirerack.com/tires/tirete...e.jsp?techid=4

 

I have checked the tire pressures again and they are fine. I have fitted a new tire to the left rear. It is the same brand but has about twice as much tread depth as the other one. I got a print out from the alignment and it was set correctly and I wasn

 

This is probably the source of the problem. Mis-matched tires. Even though they are the same brand, one is old and one new, so different traction (old rubber vs. new rubber) and different outer diameter (one worn smaller). Get another new tire for the other side. You could test this theory by borrowing a pair of matched tires/wheels from a friend and test.

 

Yes, two different tires (one worn more then the other) will cause the car to pull to one side under acceleration due to the LSD.