neal.bull

Hi All

I hope you can guide me in the right direction. I have a '09 ML350CDI with the off-road pack.

Recently my left rear drops from time to time when parked. It does not happen every time, but is becoming more regularly. The pump is almost constantly running while driving trying to keep the car level. I am worried that the pump would overwork itself and the I have another problem. The pump already sound very noisy.

I took the car in for a service yesterday and they tested the suspension, but yesterday the car was nice and level the whole time. So they could not pick up any problems.

It is not a bag, they tested that as well, but I reckon if a bag was leaking it will go down every time you park.

I have also noticed when it drops, it does that in a few seconds and you can clearly hear it releasing the air from the left rear wheel arch area, but as I said not every time.

I was wondering if it is not the rear leveling sensors or a valve malfunctioning.

Any suggestion what next steps to take to determine the problem?

Kind regards

Maj. Dundee

Neal nowadays everything is code driven. You need a scanner to read the codes. Look at all the possibilities.

wannawagon

I recently had this problem on a "new to me" 2008

I thought it was the sensors too and swapped the from side to side and corner to corner, it was still erratic

I then changed the offending corner airbag and now (been only 2 days) and all is good sofar

I must stress that in my case the compressor was not going much at all, but it was always dropping on rear right,

kombifan

in all likelihood you do have a leaking airbag.

The leak is probably in the folds of the airbag and only rears it heads during driving or at certain levels when parked.

If if you hear it releasing air from the arch and offending corner, and not the valve block. You definitely have a leak...that is quite large.

BlackML550

I've just had a similar problem or intermittent fall in the right rear side, which in turn throws the whole balance out on the rear as I've learnt. I could raise it right up and overnight it would stay there. Then back at normal height it would play up but again on an intermittent basis, but usually every day. Finally, the left hand rear bag split so I took both out to replace them. What I found was a hole in the left rear but that the right rear was torn. I couldn't understand how it would even hold any pressure. In the end replacing both bags was the solution and now it sits perfectly level.

What was was interesting was the the tears were inside the lower food of the bag which you can't see whilst it's in the car and may even seal the bag for a period of time and maintain pressure but maybe not for too long. I was amazed when I saw the tear and can only assume that as the bag sits on the base of the lower control arm that it folds up and seals any tear on the seam created by the fold.

replacing the rear bags is a DIY job and I did mine in under 2 hours with the assistance of some YouTube videos.