Mercedes Benz C-Class W203 (2000 - 2007) - 2007 3.0 - pulling to left

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Mon 9 Mar 2009 12:18
2007 3.0 - pulling to left - duncansand
Hi,
I recently purchased a merc c320cdi (w203, previous generation) - lovely car, fantastically smooth and powerful. However, the car pulls to the left slightly, so you are conscious of correcting it when driving on the motorway, for example.

I had a 4-wheel alignment done, the guy really knew his stuff and talked a lot about the fact that mercedes have a unique steering system. The alignment was only slightly out, but it was corrected anyway (he corrected the thrust angle). Whilst the car was on the ramp, the guy showed me the driver side front type - it was quite worn on the inside edge, but loads of tread in the middle. The mechanic said he was quite surprised by the wear and wondered if it was just the fact that I have a sports suspension setup on the car (my car is one of the very last w203 models, so has all the kit on it as a sell-out model).

The alignment has made no discernable difference - the car still pulls to the left.

I'm wondering what might be causing this and what my next step should be. Any advice?
Many thanks

Edited by Dynamic Dave on 09/03/2009 at 12:46

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Mon 9 Mar 2009 12:22
2007 3.0 Merc c class pulling to left - Number_Cruncher
There are some modified camber \ castor adjustment bolts available which allow an increased range of adjustment to counter the problems you're having.

Did you get a print out of the alignemt test values? Could you post them up?


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Mon 9 Mar 2009 19:38
2007 3.0 Merc c class pulling to left - piston power
Replace that tyre that is worn, now the alignment is set up correct it will still pull with a worn tyre.

You could try swapping front to rear if there the same size some merc's are not!
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Tue 10 Mar 2009 20:28
2007 3.0 Merc c class pulling to left - duncansand
Here are the details from the geometry print out:

BEFORE:
Left Front:
Camber: -0.49 (green)
Caster: 10.28 (green)
Toe: 0.18 (red)

Right Front:
Camber: -0.48 (green)
Caster: 10.19 (green)
Toe: 0.10 (green)

Front Total Toe: 0.28 (green)
Steer Ahead: 0.04 (red)

Left Rear:
Camber: -1.22 (green)
Toe: 0.08 (green)

Right Rear:
Camber: -1.16 (green)
Toe: 0.17 (green)

Rear Total Toe: 0.25 (green)
Thrust Angle: -0.05 (green)

AFTER
Left Front:
Camber: -0.48 (green)
Caster: 10.31 (green)
Toe: 0.09 (green)

Right Front:
Camber: -0.47 (green)
Caster: 10.18 (green)
Toe: 0.09 (green)

Front Total Toe: 0.18 (green)
Steer Ahead: 0.00 (green)

Left Rear:
Camber: -1.20 (green)
Toe: 0.18 (green)

Right Rear:
Camber: -1.16 (green)
Toe: 0.17 (green)

Rear Total Toe: 0.36 (green)
Thrust Angle: -0.01 (green)

Edited by duncansand on 10/03/2009 at 20:30

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Tue 10 Mar 2009 23:05
2007 3.0 Merc c class pulling to left - Number_Cruncher
It looks like the alignment has done a good job of straightening up the toe, and therefore the thrust angle.

However, there's still some asymmetry on the castor.

As per bigtee's post - another cause of asymmetry is now the badly worn tyre.

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