E46 M3 Alignment - Rear Left Camber and Toe

[happian 0]

Hi, I'm looking for some advice on my rear left side suspension.

I'm done whole rear work done during last Xmas holiday, subframe reinforcement (AKG), bushing replacement (subframe, RTAB: AKG, everything else: BMW genuine), and so on.

I have replaced rear tyres last week, and did an alignment but the guy couldn't make rear left into spec. On rear left side, maximum camber he can get to is -0.52 (spec: -2.00 ~ -1.30), and maximum toe he can get to is 0.40 (spec: 0.08 ~ 0.14)

Due to this geometry set up, my old tyres had excessive outside worn out and sharp edge near grove.

He said there should be an accident on rear left side, so that lower control arm and trailing arm were bent. Previous owner used to use this car for track day, I'm pretty sure there was no accident on this car. I can understand lower control arm can be bent, but can trailing arm be bent? I think it's quite beefy and made out of cast iron, car would be damaged more than trailing arm. 

I'm planning to replace lower control arm to SPC adjustable one.

1/ What could be possible reason for this excessive toe in?

2/ If this is due to bent trailing arm, how can I confirm if it's actually bent? Anyway to measure the size to tell?

3/ Ride height is a bit higher than spec, rear left is 625mm and rear right is 620mm. (Stock: 590mm ~ 610mm) Does this affect toe angle? (This car used to have coilover, but I have replaced to stock standard when I'm doing rear work.)

4/ Can lower control arm affect toe angle?

5/ What would be recommended approach to diagnose the issue, and nail down to root cause?

6/ Can I ignore this much difference? or Should I fix it? This car is not for track day, just street use.

7/ Any recommended shop to get second opinion?

Any help/advice would be appreciated.

Cheers, Alex.

[Herbmiester 909]

If it has been in an accident there is a small chance the chassis is bent. Best bet would be a panel beater with a chassis alignment setup.

[M3_Power 636]

Swap the control arms left to right and see if it translate into the similar numbers but reversed. If so then one of the arm is bent.

Normal for these cars to sit left side higher. They are engineered that way.