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Hi all, new here but need some advice. (UK resident)
I have a 2015 e class saloon 74k on the clock, and on a rougher road surface there is a constant knock which sounds as though its coming from front passenger wheel, I have been to 3 garages who can't diagnose the problem, I have had the garages change rear springs, front ball joints, had the shock absorbers off all 4 corners and checked they are still working properly. My next step is to change all suspension bushes out for new and hope this solves the problem, before I do this, could there be anything else that I may have missed or not even considered? I am at my last straw before the car gets sold and left for somebody else to resolve.
Any help or suggestions would be greatly appreciated
im not sure about a constant knock. but i know my front thrust arms are going. i get a knock at lower speeds under any kind of bump. your constant knoc could be from the "rough road" surface. try a smooth road see what happens.
Check the anti-sway bar links. If these are loose or worn, they will make a tapping sound when the corresponding wheel goes over imperfections in the road.
Check the anti-sway bar links. If these are loose or worn, they will make a tapping sound when the corresponding wheel goes over imperfections in the road.
This ^
These can make a constant annoying rattle when they get worse. Replacing them is a pretty easy job. If you can rotate them back and forth very easily, they are shot.
Define you knock sound.
More of metallic or more of rubbery+metallic but not all out mettalic.
Suspension, steering and engine mounting can make sound.
Where the is a :
- Rubber bushings, we have plenty
- Ball joints or moveable joints , we have plenty
- Suspension bearing and its top mount
- Engine mounts rubber internal parts
Basically any component allowing play in the name of comfort and/or requirement for controlled deflection, can make noise when they are worn out.
This is a loose sway bar link sound.
The sound is from : Between the ball joint of the sway bar link to either the swaybar or to the strut (front damper). This is not from the rubber bushing holding down the swaybar.
When I installed a Super-Pro swaybar link, their reccomended tightening torque value was too low at 40Nm and hence it got loose fast.
MB link is at 90Nm. So I use 75Nm and all good. Super-Pro was counting on their special friction washer as a good locking mechanism.
Now, the sound for mine is not from worn out ball joint of the link, but from loose-ness, so this is very metallic sound.
Ball joint threaded end "dancing" inside the provided bore at sway bar or front strut.
In most cases, noise from ball joint can come from parts below being worn out :
Simply if the ball is the piston, the housing for the ball is the liner. Ball hit liner and make noise.
Some ball joints have some sort of non metallic insert/liner.
I will give another example possible noise maker : my lower L shaped ball joint which is not yet making noise but it will in say a few more thousand kilometers.
This early wearing out of the ball joint is from track use at 20 laps. P/N is A 212 330 01 35 https://www.pelicanparts.com/More_In...-330-01-35-MBZ
The same grief happened to my swaybar link, from that 20 laps track use and 23,500KM or normal use.
The left swaybar link top side one for the strut, its boot got torn. The track has 9 right hand corners and 2 left hand ones, so left side suspension got most of the abuse.
I do my preventive maintenance and inspection VERY OFTEN and I don't wait for noise to occur from wearing out components.
Your 74K, I do not know you speak of miles or KM ? I think you speak of miles or 118,000KM.
If in Jakarta road, my city, all the arms (2) of the front suspension and the swaybar link will be super noise maker by 118,000KM, almost I can guarantee it at 99%.
The CASTER arm works harder than CAMBER arm.
This is a C200 W204 at 71,000KM but car is 2010 model year, so 10 years old when I done the inspection for my good friend.
Torn bushing rubber at CASTER arm.
Above is C200 W204 of 2010.
It is easier to name CAMBER and CASTER arm to describe the 2 arms for front suspension, by their duty/task. Below is my E400.
12-03-2022, 01:01 PM
at sway bar or front strut.
