Can anyone suggest how I can move forwards with this problem?

[Jonesy161]

An easy one to eliminate is drop links, they are easy to detach at one end, drive over bumps to see if the noises are still there.

 

[hamster8]

Surely suspension, drop links, bushes and other obvious wear items should have been diagnosed by the three previous garages.
What about taking it for an MOT check ?

Everything visible has been checked by all 3 garages. To me, if I were a garage owner or mechanic, I would be embarrassed to say I couldn't fix something. We pay garages for their expertise. I am surprised that none of them have any hindsight regarding this issue. Perhaps I might find someone who wants a challenge?

 

[Jonesy161]

One more point on drop links...........they can make a noise without being an mot fail, I’ve changed many simply because of the noise, the joints were still good.

 

[Bellow]

Everything visible has been checked by all 3 garages. To me, if I were a garage owner or mechanic, I would be embarrassed to say I couldn't fix something. We pay garages for their expertise. I am surprised that none of them have any hindsight regarding this issue. Perhaps I might find someone who wants a challenge?

The focus thus far has been on suspension components it seems and nothing found. Which implies the cause is something other than suspension (though it could still be (eg damper, ARB bush/drop link, etc)). Possibly something as innocuous as a cable or heat shield slapping around - or possibly brake related.
When the clunk next occurs (or you provoke it), with your left foot very lightly apply the brake and note any difference in sound. If the noise is quelled during that investigate the brakes immediately. If a caliper is loose on its mountings it needs rectifying immediately. Outside possibility but too serious to overlook.

 

[geoffus]

Everything visible has been checked by all 3 garages. To me, if I were a garage owner or mechanic, I would be embarrassed to say I couldn't fix something. We pay garages for their expertise. I am surprised that none of them have any hindsight regarding this issue. Perhaps I might find someone who wants a challenge?

How much did it cost for the inspections, did they do a thorough check on all components?

 

[John757]

I used to own an A160 some years back and mine had a full inspection, bought from a main MB dealer.. low miles (28,000) and after it was delivered it had a rattle coming from underneath... it sent back and they found a broken rear spring .. (so much for a full inspection!!) the last part of the top of the coil had snapped off and was rattling around in there. Spring was replaced.
It went back a few weeks later with a misfire and all the coil packs were replaced... it then developed a shunt when you came off the throttle and on again... often drive came in with a thump as you pulled away from stationary. All the issues except the autobox shunt were fixed under warranty.... I moved it on after 6 months.. shortest time I ever owned a car...

I would guess at either a rear broken spring...the top half (the top last coil) or engine/gearbox mounts worn out.

I have had a rear spring break on 3 vehicles I have owned.. its quite common.

 

[hamster8]

How much did it cost for the inspections, did they do a thorough check on all components?

The 1st garage knew me, and charged me nothing for the inspection which was very kind of them. The 2nd garage knew me, and was doing other work, so I cannot comment regarding charging. The Mercedes main dealer spent quite a time checking everything, and made a vehicle report video. They also charged me nothing, which was very kind of them - but still have the problem of course.

 

[John757]

I don't think main dealer 'fitters' would have seen many 2006 A classes.. I have little confidence in them... A friend of mine left his G500 in a main dealer for a week and they couldn't solve his electrical problem... it went to an indie in N London, within 30 minutes using the same computers MB use the fault was traced (dry joint on a K40 relay pack) The indie works on Supercars... so it wasn't even their bread and butter.

I know this is annoying you.. here is what I would do...

Jack the car up, one wheel at a time... this will take the load off the springs... remove the wheel... and give the springs a good tug and shake... they should not move or make any odd noises... look right up to the top of the spring. Have a look yourself at the ball joints... if they have rubber covers, are they split or cracked... if they dont is there rust on any ball joint surface.. check the brake cables are not loose an rattling about, check everything under there is tight... any leaks apparent from the shock absorbers.. make a list of things you have looked at yourself.. give the suspension a good wobble... and at all the bolts holding it together, look for something that might indicate something is chaffing, worn, or worn-out. wheel arch liners.. everything... look at the exhaust pipe... do the rubber hangers look worn out or broken... photograph the bits you check.. ping them up here.. someone will spot something... it might take some time... but eventually the source will become apparent .

I would always go to an independent Mercedes Specialist over a main dealer , especially something from 2006.

good luck keep trying

John

 

[MrGreedy]

My experience on a 2004 w203 c class was broken springs on the top at the front, and at the bottom at the rear. Purely for reference.

 

[JHS]

Surely suspension, drop links, bushes and other obvious wear items should have been diagnosed by the three previous garages.
What about taking it for an MOT check ?

As should a broken coil spring. A previous SLK had 2 rears break and yet pass the MOT.

 

[hamster8]

PROBLEM IS POTENTIALLY NOW RESOLVED. (Once I've had the work done.) Thanks to everyone who has tried to help here. I went and had a poke around with the o/side frt. corner (where I had originally found the noise to be coming from.) It was EASY to find the source of the noise. It is the rubber cover at the top of the shock absorber that is dancing around. I can't see well in the roadside, but there must be a piece of metal attached to it, and the cover is knackered and continually moving about. That is the source of the noise! In view of this, I am ASTONISHED that the garages never picked up on this. The Mercedes main dealer mentioned these in their vehicle report. That led me to go and investigate myself, and it is blatantly obvious that this is the source of the noise! I am delighted that the mystery is finally solved!

 

[SeagullFan]

That’s good news, rattles, squeaks and groans drive me mad when i’m driving, that’s why i always leave the other half at home

 

[John757]

Congrats....very satisfying solving these things yourself

 

[unclebuck]

Worst one I had in one of my old cars was a bloody stone caught in one of the arms clanking about, took ages to find.

 

[hamster8]

The dustcover on the shock absorber has what appears to be a nylon ring at the top. This has become separated from the rubber and this is the source of the noise as it flaps about in all directions on the shaft of the shock absorber. No metal is involved.