Rear wheels going opposite way 07m35 sedan

[m35manny]

Hello Nico members!
2 weeks ago as I was driving something on the road bounced off my wheel and hit my gas tank which in turn pierced it. I had to stop at a firestone about a mile away cause of a fire risk. So the guys at firestone helped me out and ordered me a gas tank. I authorized them to do the work. Now a couple days after getting the car back, I noticed that when i'm going over 30 my rear tires turn the opposite direction when they hit any bump, small or big. It feels like i'm gliding/sliding. I know it is very dangerous. I gave the guys a call back at firestone and they test drove it and said it was an alignment issue. Now i'm no mechanic but this doesn't sound like an alignment issue to me. Anyways, on the day I was supposed to get my free alignment, their alignment machine broke down. So now, i'm waiting on them to call me when it's fixed to go get my alignment. I know they had to remove my rear differentials and rear suspension to get to my gas tank. Could they have done something wrong? Or is this really a symptom of a bad alignment? I know what it feels like when you need an alignment, and this feels nothing like it. I have scoured the internet for answers but can't find an answer that relates to me. I hope one of you can enlighten me. This is my only car, and I haven't been able to drive much or far due to this! Any help is appreciated

Thank you!

[AZhitman]

It absolutely is an alignment issue. Too much rear toe will cause that "hopping to the side" sensation you describe, and it is VERY unsettling.

Your experience has been with front-end alignment (wandering, tramlining, pulling to one side). Rear wheel alignment issues cause exactly the issue you described.

My concern would be further damage, however. If you hit something hard enough to puncture the tank and knock the rear out of alignment, I'm guessing something's bent beneath - Get it to another shop, and don't worry about the "free" alignment.

[merlinq2]

Drive shaft may not be set properly - not centered nor properly secured

[m35manny]

It absolutely is an alignment issue. Too much rear toe will cause that "hopping to the side" sensation you describe, and it is VERY unsettling.

Your experience has been with front-end alignment (wandering, tramlining, pulling to one side). Rear wheel alignment issues cause exactly the issue you described.

My concern would be further damage, however. If you hit something hard enough to puncture the tank and knock the rear out of alignment, I'm guessing something's bent beneath - Get it to another shop, and don't worry about the "free" alignment.

Thank you AZhitman. I will take it to firestone once they fix their machine, if it continues I will go elsewhere.
Greetings from Phoenix!

[Boonies]

Don't delay, go get it aligned somewhere else, it is dangerous to drive if your handling is affected that dramatically and is wearing out your tires each mile you travel.

[m35manny]

Took it to get aligned today and it is still doing it. Manager at Firestone has no idea what it is, so he is taking it to the dealership himself Thursday. Does anyone have any idea what it could be? It doesnt look like whatever pierced my gas tank damaged my suspension. I think it is more of a technician error. It wasn't doing this after the object pierced my tank.

[AZhitman]

Whatever it is, it is causing the rear suspension to deflect. Did they give you the specs on the rear alignment?

Are you in Phoenix? If so, Network Alignment is one of the only places I trust. I've been taking my cars there since the late 80's.

[m35manny]

After doing some research I have learned that it is the rear active steering system that is making my car "glide". The technicians must have done something wrong. Is there anyway I can turn this off from inside the car?

[AZhitman]

Ugh, that's not good. Something may have gotten damaged.

Have a look through the FSM: http://www.nicoclub.com/FSM/M/2007_M45-M35/

I don't have time right now to hunt it down, but section IDX is the index.