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A good alignment makes an R107 track straight and wear its tires evenly. A bad one makes it pull, wander or chew through the inside tire edges. Here is what matters and what to tell the alignment shop.
Why the R107 needs a careful alignment
The R107 has front suspension with adjustable camber and caster, adjustable toe, and rear semi-trailing arms with limited adjustment. Many alignment shops do not know these cars and use generic settings. Ask for the Mercedes specifications for your model and year, and confirm with the factory manual.
What each setting does
- Toe: how much the front wheels point in or out. Wrong toe wears the tire edges and makes the car wander.
- Camber: the inward or outward tilt of the wheel. Wrong camber wears one side of the tire.
- Caster: the tilt of the steering axis. It affects straight-line stability and how the wheel returns to center. More caster gives better stability.
Typical approach
Mercedes publishes alignment specs with tolerances for each model and year. Many specialists set caster at the higher end of the allowed range for stability and set toe close to the nominal value. Exact values vary by model and year, so I do not quote numbers here; get them from the factory manual or a specialist. Camber and caster on the front are adjusted with eccentric bolts on the lower control arm.
Before the alignment
- Fix worn parts first: ball joints, tie rods, idler arm and bushings. See front end rebuild and idler arm.
- Check tire pressures and tire condition.
- Make sure the car sits at normal ride height; tired springs affect camber.
- If the car has been lowered, tell the shop; see lowering.
Why it pulls
- Uneven tire pressure or a damaged tire
- Caster different from side to side
- A sticking brake caliper
- Worn suspension parts
Why it wanders
- Too little caster
- Worn steering parts or a loose steering box
- Toe out of spec
What to ask the shop
Ask for a printout of before and after readings, the use of the Mercedes specs for your car, and to set the steering wheel straight. Ask them to check rear toe and camber too.
Quick answers
- How often should I align it? After suspension work, or if the tires start wearing unevenly.
- Can I align it at home? Toe can be checked at home with string; camber and caster need equipment.
- Will an alignment fix a vibration? Usually not; a vibration is balance, tires or the driveline. See shimmy and vibration.
