mercedes w210 knocking help needed

[L_A]

Hi Guys,

My car has started making a knocking noise from the front and somtimes feels like the rear end the sound kind of travels so you cant tell where its coming from but feels more to be more from front end (so annoying). Its when i am driving along hitting potholes or uneven surfaces when i feel it. Its not a major knocking sound however it is annoying as the car had a very tight ride before however now it feels very loose and cluttery. I have had the car lowered slightly however this was over three years and has never gave me any problems till now. i was advised on getting bottom ball joints changed about 6 months ago however car felt fine so i left it. When i started experiencing this knoocking problem i automatically thought that it was the bottom balljoints however after having it checked by kwik fit then the a independant dealer say there is no play in balljoints and everthing else also seems to be fine. What could this problem be Any ideas?? thanks in advance..

 

[BenzComander]

Drop links, broken spring, breaking corroded spring cup, springs seized in spring seats (caused mine to twang!) etc!!

Someone else will be along soon and probably ad to the list!!

 

[Benzowner]

Usual culprit is the track rod bushes, mine last about 50k miles then start rattling again.

ooops meant anti roll bar bushes ah well senillity never come alone

 

[mark.t]

loose exhaust ......drop links .......

 

[Parrot of Doom]

My money is on the drop links. Dead cheap and a 10 minute job each side.

 

[jaymanek]

Drop Links without doubt...

 

[L_A]

Looks like drop links will have to be replaced if it is that cheap and simple. Then i will take it from there if anyone else has any other suggestions please let me know i will keep you posted of what resolves this knock.. Thanks to all that responded..

 

[jaymanek]

Well no one said simple! They can be an absolute pain to refit at times, and i must have done around 20 sets so far and still not perfected it... i have been trying to fashion a tool just for this use, but not getting very far...

 

[Alex Argent]

Anti-roll bar bushes/mounts? (Common problem on certain models).

 

[Davidash]

I have replaced all of the parts mentioned, I have also had the steering rack overhauled. I still have a knocking on paved or cobbled surfaces. I have been told by the experts that it is worn teeth in the steering rack. It is apparently common in Mercs and BMW's. You either buy a new rack or they find a 2nd hand one which they overhaul and fit.

 

[Dieselman]

But you've already had the rack overhauled...

I would expect the rack to exhibit play before knocking.

What about the top ball joints and try grabbing the car by the roof and rocking it violently side to side, that should check out all anti roll bar components.

 

[Davidash]

Unfortunately, when they "overhaul" a steerinmg rack they sometimes just replace the seals and the rubber boots and re-chrome the shafts if they have rusted. Generally they cannot overhaul the rack gears and they are either replaced with a new or second hand rack. I would guess that the gears on your rack have worn badly.

 

[Birdman]

I got occasional tapping sounds over potholes/cobbles from the rear RHS which defeated the garage for eighteen months and they've checked everything that's been mentioned here. I even removed the boot trim and clambered inside with a torch. Best bet currently is something loose behind the rear seats & knocking against the bodywork. Had rear acceleration sensor replaced yesterday - it had become unbolted from the R/H wheelarch and displayed unclearable fault code - so maybe that was it.