W204 Front Strut Mounts Advice

[gibsonk]

Another question to those who are far more knowledgeable than me, if i may please.

I have a knocking on the front of my car that is either down to the front struts or the mounts, I will start with changing the mounts to see if it cures it if i have to go for struts i may just jump for coil-overs.

What i am not clear on is, do we have to replace the complete mount or is it just the bearing that is the issue.

The rest of the running gear (bushings, thrust arms etc. have been checked and are all good) so it just leaves me the struts or mounts(bearings)

Many thanks in advance

 

[paul73mt]

do you notice this more in reverse with some steering lock on??

 

[gibsonk]

do you notice this more in reverse with some steering lock on??

Not really noticed, the only place i really do that is reversing onto my drive which is smooth.

I have noticed if pulling up slowly over a lowered kerb on steering lock its more prevalent

 

[paul73mt]

it could be the trust bushes there known for it, but it normally shows up when you reverse and have some steering lock on it. Did they check the springs and struts when it was up in the air?? I think their quite heavy on the front so could be spring esp if you hit pot holes etc. I must admit i haven't had and springs replaced but i most of the other stuff has been done. How many Miles you got on it ???

 

[gibsonk]

it could be the trust bushes there known for it, but it normally shows up when you reverse and have some steering lock on it. Did they check the springs and struts when it was up in the air?? I think their quite heavy on the front so could be spring esp if you hit pot holes etc. I must admit i haven't had and springs replaced but i most of the other stuff has been done. How many Miles you got on it ???

They checked the springs, bushes, arms etc. and gave it the all clear, so i assume they did the struts, leaking strut is pretty obvious. I guess without taking the struts out the top mounts cant be checked. I have come back to the Torque\Thrust arms myself, need to get under myself and take a look.

I have just under 80k on the clock, rod ends replaced recently

 

[paul73mt]

with the thrust arm bushes i believe they did change the bush and also now comes with some 'dust' caps that cover each side, Their not easy to change without the right gear, I had Mine done by Wayne Gates but he managed to push them out easy with a hydraulic bearing pusher so didn't take long at all. Mine has just coming up to 120K so far so good

 

[markjay]

You can replace either the mount (rubber), bearing, or both - depending on which component failed.

A failed rubber mount will likely cause knocking, a failed bearing will likely cause grinding noise when turning the steering wheel.

But there's no need to replace the entire strut.

See also:

W204 Front Hydro Bushing

 

[190]

Front struts on a W204 can fail internally in a way that causes them to knock. A replacement strut under warranty cured the problem on mine. As far as I know they didn't replace the mounts.

This service bulletin might help although beware it's written in MB speak:



Front Strut / Shock Tower: By Symptom

Technical Service Bulletin # LI32-25_P-048381

Date: 091208

Suspension - Front Axle Dull Thumping Noise On Bumps

NOISES FROM VICINITY OF FRONT AXLE ON UNEVEN ROAD SURFACE

Topic number LI32.25-P-048381 Version 1

Design group

32.25 Shock absorbers/damper struts/spring struts

Date

12-08-2009

Validity

Model 204 without code 483 (Vehicle dynamics package), without AMG; Model 204.0## #A 185017 up to * 195993 with head bearing

Reason for change

Topic extended to FA shock absorber / torsion bar linkage. / Supersedes DTB P-B-32.25/67

Reason for block

Complaint:

Dull thumping noises or metallic rattling from vicinity of front axle on slightly uneven road surface and/or repaired road surface.

Note:

Noises occur in lower speed range (20...approx. 70km/h).

Cause:

Several causes are possible:

1. Head bearings on front axle suspension struts are too stiff (Shore hardness).

Note:

Noises from the head bearing occur on more uneven surfaces and sound relatively dull.

This cause affects only a small, limited production batch! Pay attention to the VIN restriction for head bearings (EPC: "Bearing, suspension strut to
body") in Validity section! On vehicles outside the restriction range, the head bearing is not the cause of the noise and may therefore not be replaced.

2. Shock absorber

Note:

Noises from the shock absorber are audible on slightly uneven surfaces and sound rather more metallic.

3. Torsion bar linkage

Note:

Noises caused by a torsion bar linkage only occur in a very small number of cases on this model series.

 

[Yugguy]

What year is your car? Preface like mine had issues with the shocks that cause knocking on low speed bumps. You can't see the issue from the outside. I changed both mounts and shocks on mine cos of this.

 

[Yugguy]

Ah yes just seen 190s post. That was my issue.

 

[OneForTheRoad]

Arb link arms.

 

[gibsonk]

Looks like I am going to fit new shocks, springs and mounts all round, for the price of OEM front shocks, mounts (may as well do the springs while it's off) and labour I can get the bilstein Pro kit or coilovers for not much more