New Car Knocking

[simba23]

Hi Guys

Still new to this forum having bought a C Class Coupe in March this year.

As per my previous posts i have been loving the car in terms of performance and styling.

I have noticed in the last 2 weeks when parking and only when in reverse or when doing a 3 point turn there is a knock/clunk under the car.

It feels like some part is under pressure or even broken.

Today i had to reverse up a slight gradient and the car knocked/clunked repeatedly up the hill.

I was attending a meeting but was so concerned that a wheel was going to come off that i checked all the wheel nuts were tight.

There was room for tightening and i did, the knocking is still happening when parking in reverse gear.

This issue is beginning to knock my confidence, Prior to this car i have never owned a Mercedes and have owned Porsches, BMW's and a Bentley. Ive never come accross anything like this. I have an E63 on order and am now having second thoughts. Have you guys got any ideas on this?

 

[Adam230K]

really strange for this to happen on a new car... must be something loose somewhere... if it were a much older car i'd say one of the bushes in the propshaft but i just don't see how it can be the case with a brand new car

 

[Adam230K]

get it to the dealers asap

 

[steve333]

Best to get the car on a ramp & have someone have a good look under with an inspection lamp,something doesn't sound good.

 

[simba23]

It's a weird one it does it only in reverse irrespective of the steering turning or not.

 

[SammyC]

It's a weird one it does it only in reverse irrespective of the steering turning or not.

Could be a transmission issue in reverse gear. Something lose down in the gears.

If so that ain't a good start for a new car.

Get it to the garage asap

 

[BlackC55]

As it's new and under warranty to help the tech diagnose it demonstrate it to them so they hear it. So many times they dont know how to replicate it like you can.

 

[Dieselman]

Parking brake cable rubbing on the propshaft.

 

[grober]

Dealer ASAP--- don't delay. Could be many things but if it only happens in reverse then everything in the drive train from reverse gear back is going to be suspect- so from an autogearbox problem through propshaft- differential -drive shafts and rear brake/ hubs

 

[simba23]

Thanks guys I'm going to try getting it booked in ASAP will report back.

 

[simba23]

Definitely not engine knock the sound comes from around the passenger footwell vicinity.

Generally the car drives really well.

 

[nadeem]

broken spring or sub frame bushes?

 

[simba23]

Just a quick update the car has been in to the dealer they have replaced a ball joint which in their words was not faulty but seems to have cured the problem. Now, although the problem seems to have gone. There is a squeak/ squeal from the passenger side of the car. It's not continuous, only at less than 20mph and more so with when there is a passenger in the front.

I have tried driving gently with the hand brake on in case the brakes need wearing in. I've also done a few hard stops in case there is any film on the discs.

I'm thinking now, could it be a spring issue? (not the season hence weather)

 

[grober]

Sounds as if its all anti roll bar related. They have drop links that have a ball joint or two on them. Its possible your antiroll bar is now getting a bit more "exercise" than it did before and possibly the rubber bushes are protesting a bit. If its that a little lubricant in right place should quieten things down nicely.