Recurring Front Wheel Humming After Side Impact – Replace Knuckle or Bearings Again?
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Recurring Front Wheel Humming After Side Impact – Replace Knuckle or Bearings Again?
Hi everyone,
I’m looking for technical advice regarding a recurring front wheel humming issue.
Vehicle:
2013 CLS Shooting Brake (X218, RWD diesel, W212-based suspension)
Background:
The car had a diagonal guardrail impact on the driver’s side some time ago.
After the impact, I developed a humming noise above ~40 km/h that increased with speed and became louder under load while cornering.
I replaced both front wheel bearings (hub assemblies).
The noise completely disappeared and the car drove normally for about 2 years.
Now, the humming has gradually returned with the same characteristics:
There are minor cosmetic scoring marks but:
Thanks.
Non Driver side steering knuckle
Driver side steering knuckle
I’m looking for technical advice regarding a recurring front wheel humming issue.
Vehicle:
2013 CLS Shooting Brake (X218, RWD diesel, W212-based suspension)
Background:
The car had a diagonal guardrail impact on the driver’s side some time ago.
After the impact, I developed a humming noise above ~40 km/h that increased with speed and became louder under load while cornering.
I replaced both front wheel bearings (hub assemblies).
The noise completely disappeared and the car drove normally for about 2 years.
Now, the humming has gradually returned with the same characteristics:
- Starts above ~40 km/h
- Increases with speed
- Louder under load while cornering
There are minor cosmetic scoring marks but:
- No deep grooves
- No visible cracks
- No blue heat discoloration
- No obvious severe deformation
- Could a slightly distorted steering knuckle from the original impact cause premature bearing wear even if preload was correct?
- Is it possible that minor spindle surface imperfections are enough to create alignment issues leading to recurring humming?
- In this case, would you replace the bearing again only, or replace the steering knuckle as well?
- Have you seen impact-related cases where bearings temporarily fix the noise, but underlying knuckle geometry causes recurrence?
Thanks.
Non Driver side steering knuckle
Driver side steering knuckle
