knock/thump noise over bumps W211 E220CDI

[dec1777]

I have just bought a 52k miles 2002 E220CDI (first merc) which i am very happy with. I still have 3 months dealer warranty (independent garage) and was hoping you guys could help diagnose a single knock/thump noise from the front nearside suspension/wheel when driving over even a small bump.

It appears more aparent at lower speed and over small bumps as opposed to potholes however that could just be my perception of what is happening.

The car had balljoints replaced according to dealer service records around 48k miles and while they acknowledge the knocking sound they couldnt find the source and it is nothing to worry about.

Personally id prefer to see themem fix it and was wondering if there is any common problem being overlooked or anything I can check (with very limited DIY knowledge past an oil/filter change) to see if I can identify the source of the knocking before going back to the dealer.

Many thanks

dec1777

 

[SQ_W211]

It could be your shock/s but you will have to listen to which side it is coming from first and then diagnose it. what kind of knock is it?

Oh and welcome to the forum

 

[television]

welcome to the forum drop links and or the rollbar bushes are the most common for a slight knocking

 

[SQ_W211]

you can also read this post to see if it helps

http://forums.mercedesclub.org.uk/showthread.php?t=31765

 

[GEORGEROV]

Hi dec, If it isn't any of what malcolm mentions above, and it just appeared after the ball joints were done then I wonder if the garage put the suspension back together correctly. If the sprint/strut for example was disturbed and not located properly . I've seen cases where the top mount (of the strut) and spring alignment was out causing a knock as mentioned. Just a thought!.

 

[dec1777]

thanks for the replies folks, i have a local friendly, if slightly agricultural mechanic who is going to look at it with me over the weekend, so these pointers are great.

It is only a slight knocking sound or rather a single clunk so will have a look at the drop links and rollbar bushes first.

Only have the car since last Friday so no idea when the problem first showed up. Thanks for the help hopefully this will help me gather enough ammunition to ensure resolution with the dealer I bought the car from.

.... and i have to add...... £190 for a replacement spare key, the world has gone mad!!! first car ive had that couldnt have a key cut at the locksmiths LOL, .... my image is ruined

 

[television]

http://www.detali.ru/cat/oem_mb2.as...GM=716.649&CT=F&cat=64U&SID=32&SGR=060&SGN=02
In the link above you have the roll bar components

Re the key, backin the 70's I had a bunvh of around 250 car keys, and I could gain entry to most cars with them, think that if this was still the case and someone like me just drove your 211 away

 

[dec1777]

cheers for the link Malcolm,

100% agreed on the keys, i remember a time not that long ago when i could leave my car keys in the ignition and the car unlocked all day long, those times have gone,.... and while i still think £190 is a little rich for the key technology, in fairness the price for most Merceses parts that i have seen so far are no-where near as bad as i had expected, i am thinking of suspension parts which may be causing my knocking problem.

apologies for diverting from topic, when i get a resolution to this I will post back, nothing worse than threads like this with no resolution posted

thanks again

 

[television]

These suspension components are not expensive from MB, so that is one consolation .

Always nice to have feed back after its fixed, it closes the thread for others reading it

 

[dec1777]

quick symptom update......

the knock or thump noise when going over a bump seems to be the extreme of a low frequency rumble which is there all the time.

The car is new to me (<300 miles in it), so until I drove it down a rough concrete lane tonight I could not differentiate the rumble from the normal road noise of the car. (...thats my excuse anyway!!)

Not sure if this changes any of your opinions

 

[Ellsy Tanners]

Check for wheel bearing free play, may need to be adjusted. Or still the anti roll bar or lower ball joints IMO

 

[dec1777]

thanks Ellsy, a trip to the local indie ramp is planned for Saturday, hopefully have some answers then

 

[dec1777]

Quick update,

Had the car in for wheel balancing today and while on the ramp i tried rocking the wheel back and forward, there is a little vertical but no horizontal play on the side that is making the clunking noise.

My mechanics lift was tied up over the weekend so hopefully will get a proper diagnosis this week, however is this looking more like ball joints?? .... i mentioned earlier that the ball joints were replaced however the invoice does not specify which joints were replaced

 

[CLK430]

Any final diagnosis?

I have very similar problem with my w208 CLK430 with a knocking noise in the front suspension during big bumps / uneven roads / or pulling into a driveway at an angle. Sounds like a thump or a knocking noise. I have had this car for a while now and the noise is getting progressively worse!

I have replaced all four shocks / steering damper / and center drag link and tie rods! (this has made for a better ride but still a creaking knock noise!)

All help would be greatly appreciated!