E46 M3 Veers Right!

[Ayham]

Let me begin by a history of the car..It's the last E46 M3 to roll out from the factory, it has 86,000km on the clock, SMG II, convertible, 19" rims, fully loaded. The car is running on new Michelin PS2's, no suspension mods, no accidents. Two rims had pot hole damage and were fixed and aligned, they're perfect. No steering vibration at all.

For a year now, when driven on a straight line and left to steer itself the car would veer to the right. The car was taken to Pirelli by AGMC for an alignment job and the problem is still there. We took it to Hankook, re aligned it, and the car still veers to the right. Then the technician, Kevin, swaped the front tires and now it veers more to the right. But that's normal since both tires have uneven tread wear and it'll take some time to even out. I looked at the tires, they are new. Bushings and tie rods look brand new, the car is never abused. There's a 0.5deg camber difference between the front tires (driver side > passenger side) and my first guess upon testing the car is that this is the problem. Since the passenger side has less camber, then it has more traction when driven straight. However, camber cannot be adjusted according to Hankook (!!).

Anybody with a similar problem? Any clues on fixing it? It is seriously annoying and a rather silly reason to not enjoy the M3!

[akanso]

maybe because of the pot holes, try changing the rims

[Ayham]

The rims are fixed and aligned...It was a small pot hole damage on each of the two rims.

[mahmoud_bedewi]

why is the camber adjustment not possible?
this means the damage might have reached some of the suspension mounting points in the chassis or the sub frame (something might be out of position)
and what about toe in ?

[Ayham]

Toe is even on all 4 corners...It could be that one of his control arms is a bit out of shape. But I don't want to solve the problem by elimination!

[Stratus650]

Im having -2 camber on the front right, and -1.1 camber on the front left, and this is the way my car can go straight. the camber don't have to be the same for both sides. You need to add camber, which should be possible, on the right side.

i know a guy in aweer who can solve this, near the User cars showrooms.

[Bruno]

does it veer to the right when you accelerate or just on normal driving?... could it be the RTAB?

[Ayham]

Normal driving...

[mahmoud_bedewi]

i still insist that camber cannot be adjusted means something is not proper, and i agree with ayham in the control arms and i add subframe, or something worn

[Ayham]

Well, camber is produced from the control arms shape + struts hat offset..I looked at the FCABs and they look as new. I don't know if they were replaced by AGMC, most probably not.

I've been in touch with Motaz from TAM Auto Engineering and he suggested something that's very viable; chassis. Motaz used to race his EVO 9 extensively at the Autodrome, and after a full season he took the car to Polymar for chassis measurements. The difference between the two engine supports was a whooping 4.8mm!! And that's on a car with all sorts of reinforcements driven on a tarmac FIA track.

Come to think about it in retro spec, a convertible is much more prone to flexing and bending, the car is driven daily, goes to Burj Dubai site, then it's natural that things like the control arms would bend. If we only have a set of new ones to test the theory. Anybody knows if we can take accurate measures to the arms?

[mahmoud_bedewi]

control arms will never bend unless u hit something really nasty for example u hit the curb or the pavement, i have seen one with my own eyes, but it is so difficult that it just flexes due to uneven roads
but still if the car wanders to right it means it is severly bent or deformed ie it can be seen with naked eye with a bit of accurate look
i have a funny Q, is the steering wheel balanced and centered?

[Bruno]

mahmoud.... it's not funny i had that issue. for some reason my steering wheel wasn't centered

[Ayham]

Steering wheel is centered. And no my friend, control arms bend under regular use. Probably by placing it atop a brand new one we can pin point the problem.

[mahmoud_bedewi]

let me tell u ayham thateverything in a car can bend under normal use but temporarily,then it recovers its original dimensions when the load is removed
a permanent bend has to happen because of impact or shock, i have seen cars that live 30 years without doing such behavior, we are talking about egyptian streets here so very heavy duty
yet i have seen cars with similar symptoms after hitting curbs or bumps

[Ayham]

Well according to the owner, it hasn't been hit before.

But bent control arms are not an uncommon issue, trust me. Yes, usually their ball joint would snap long before they're severly bent, but we've seen bad control arms without being in an accident. I'm not saying they're easy to bend! But it's possible...

So let's list the possible culprits:

- Control arms; hence camber issue
- Chassis alignment
- Possibly FCABs & RTABs

Bruno, can you update us on your issue when you had the M3?