W203 rear knocking/clunking

[OliverLloyd96]

Hi guys,

Last night my car started to make a knocking/clunking noise from the left side of the rear of the car. It doesn't happen when going over bumps in the road just when pulling off and braking. On the flat it hardly does it but I live on a hill and it does it without fail when braking to a stop on the hill. I've read other posts similar to this issue but none completely match my issue. I'm guessing it's a suspension issue, does anyone know what it could be? I spent £1000 on replacing injector seals and front suspension parts last week now this happens, very close to getting rid of the car, guess it's just getting too old (54 reg)

 

[chrisk2010]

Hi oliver,

I have a knocking noise on mine which is very but it does happen when i go over bumps. To describe it it sounds like something is in the boot (on the left side) banging agaist te chassis.

I suspect mine is probably anti roll bar bushes or drop links i have the parts but notthe time to fit them. The springs are common to go but i checked mine and can't see anything broken, the good news is they are far easier to replace than the front.

Sorry i can't shed any light on it for you as i have probably done as many internet searches as you as nothing pins it down.

 

[OliverLloyd96]

Ye I was wondering if I had a broken spring but it would be making a noise when going over pot holes wouldn't it I think?

I just went in the car then and if I brake quite heavily from about 30, its like 3 quite big knocks, kind of like judders, it's quite hard to explain haha. Dad seems to think it's either somethings loose or the shock absorber, I don't think it's the shock absorber as if I push down on the back of the car there isn't any sound?

 

[chrisk2010]

I really don't know if this helps but I have found my noise.

The spring is fowling the wishbone:



See that rusty mark on the on the spring? It sounds like my fuel tank is loose, I found it when I was changing the droplinks and anti roll bar bushes this evening.

Not sure why it's rubbing yet as the light was gone by the time I replaced the parts but could be the shock is gone, shock mount or the spring is ready to break. I haven't hit any pot holes at speed BUT on changing over to summer tyres I noticed a dent in the rim so maybe the previous owner did and now the damaged is showing itself?

 

[OliverLloyd96]

Ah right, what do you think needs replacing then? How long have you had your car, how many miles is on it?

 

[chrisk2010]

Ah right, what do you think needs replacing then? How long have you had your car, how many miles is on it?

Not sure yet, two years and 55,000 miles

 

[chrisk2010]

I don't know if it helps but i found this.

Mercedes C200 (& others) knocking noise at rear – Diagnosis

The replacement

Mercedes C Class (W203) Rear Damper Replacement

 

[OliverLloyd96]

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[OliverLloyd96]

it sounds very similar to this, but hard to tell exactly how it sounds from in the car

 

[brucemillar]

Oliver

You know that sound travels. My W203 Estate Wagon developed a heavy clonk at the rear. Sitting in the drivers seat you could clearly hear it clonking at the rear end.

The culprit was the Front Drop links. Coupled with the Front ARB Bushes.

Together they allowed the ARB to clonk the chassis. Sound was transmitted back along the chassis rails to transmit from the rear sub frame.

You need to get the car in the air and pull these linkages around with a big pry bar. They should have minimum movement.


Sent from my iPhone using Tapatalk

 

[chrisk2010]

As bruce says above the sound emphasises and moves and i really thought mine was going to be the ARB bushes and droplinks which is why i changed them until i saw what was really happening. I'm not saying your will have the same problem as mine but the ARB bushes and droplinks are fiddly but easy to do so it's nice to start with the common cheap stuff when doing car DIY.

Mine has no doubt hit nasty pot hole at some point which is what has caused the noise.

The best way to describe my sound is like someone in the boot tapping on the left side panel with a hammer.

Edit:

To add i wouldn't have seen mine if i didn't decide to put the summer wheels back on and changed the droplinks and ARB bushes as the spring sits in the wishbone and until i lifted it up taking the weight of the suspension it wouldn't have shown itself.

 

[OliverLloyd96]

Think I've found what it is, seems to have rusted through and snapped! shouldn't have this rust been picked up in a service? had a B service in January

 

[chrisk2010]

That’ll do it glad you found it

 

[OliverLloyd96]

should the indie have seen how rusted that arm is (not sure what it's called) when it was serviced?

 

[chrisk2010]

It depends if it was part of the service or not really or if they were specifically asked to find the noise.

The problem with any garage is you can argue it till the cows come home.

I had a horrible screeching noise when i turned the steering wheel and took it to an independent garage twice the first time they told me it was the control arm and showed me it was moving on the bolt, I wasn't very convinced as it wasn't moving very much but said thank you after receiving the £200 quote and went away and replaced it myself for £50 odd. I still had the noise so i took it back and said it's not that so they looked again a bit more thoroughly and found it to be a heat sheild around the steering column and charged me £40.

I wanted to argue the control arm but to be honest it would have need replacing at some point anyway and i'm a bit more warey of that garage not because they miss diagnosed it but because they misdiagnosed it and nearly got me to payout £200 that would have done nothing towards curing the noise. Did they know it was the heatsheild in the begining and tried making it worth their while? who knows.

I did take the car tomy local F1 who are generally honest and pretty good but at least they said they don't know rather than randomly replcing things.

If i was you i would find two control arms one for each side and then find a garage that will fit them cheaply like i'm doing with my springs.

Mercedes and another garage want £362 to replace them so i've bought the springs at £64 each after a bit of ringing around and founf three garages that will fit them for £40 a side so i've saved £152.00.

Edit:

Sorry to add with W203's i'm finding they are notorius for suspension parts going which is why i'm slowly replacing arms and links ect as i go when disposable income is available.

 

[OliverLloyd96]

Ye you can save lots of money but doing work yourself, i need to start learning how to do maintenence jobs, like ive done brake disks and pads before but havnt attempted to do anything else.

Yesterday i got that control arm replaced, and replaced the multipin socket, filter and atf, which came to £320. These are all things i could do myself and save a lot money doing so, which would help being a student

 

[Lqman]

What did you replace?name of part

Think I've found what it is, seems to have rusted through and snapped! shouldn't have this rust been picked up in a service? had a B service in January

 

[Petrol Pete]

Hello Lqman and welcome. Post #16 is more than 2 years old and the OP has not been active on this forum since October 2020.

You might want to start a new thread asking your question . Best of luck