W124 Self levelling suspension check

[dstrong]

Hi,

Can anyone please tell me a simple way of checking the operation of the self levelling suspension on my 300TE-24. I have a tow bar fitted and it seems mighty low to the ground when the car is loaded up and the trailer tent attached. I am off on holiday in a couple of weeks and would like to have the peace of mind of knowing it is all ok.

Cheers

Darryl

 

[talbir]

With a load of approx 120kg in the boot, the self-levelling suspension will be activated. The levelling control arm on the rear roll bar drops and opens the valve, allowing the rear struts to be pumped with hydraulic oil, thus raising the car and 'helping' the springs.

Firstly check the level of the oil in the hydraulic reservoir, with engine switched on and no load in the boot.

Basically, the car should NOT sag at the rear under load - if it does there may be an issue with the accumulators, which maintain pressure.

Cars with conventional shock absorbers at the back will sag under load, but self-levelling cars will NEVER sag and always remani level.

 

[Peter 300TE]

it will sag slightly once loaded until the engine is running remember. also if you have the sportsline suspension they always look low, watch those speed bumps!

 

[andy_k]

if it sags under load it's unlikely to be a problem with the accumulators (at least as far as I understand the system). If it's not raising the rear of the car then you need to check the valve is functioning, the fluid in the system is at the correct level and that the shock absorbers aren't leaking.

The accumulators only effect the damping not the ride height.

Andy

 

[dstrong]

thanks guys, one note, how do I know if I have Sportline suspension??

 

[TimN]

It sounds like the exact same system as the 123 series which I have. You know that it is not functioning correctly when the rear view mirror is only showing you tarmac.

If the rear end sags after the car has been parked and the engine switched off, then the self levelling valve over the rear axle is not holding the fluid and should be refurbished. On the 123 series this was surprisingly cheap and quick to do as with a host of spanners and sockets it can be done on the vehicle. Believe me you do not want to take it off as the flow and return pipes will shear.

If the ride height does not adjust itself at all when loaded the valve is either etremely worn or there is no pressure in the system. The exact pressure can only be measured by a Mercedes approved garage but you can have a look in the fluid reservoir when the engine is running. You should see the fluid coming out of the filter into the bottle.

Other things to check are; Worn knuckles on the levers and linkages connecting the valve to the rear torsion bar and (If it is like the 123) what the disk transfering the drive from the camshaft to the pump has not been removed.

 

[MotardMan]

I can send you the factory manual testing procedure in PDF format if you want it.

Mail me off list. james.darling@eds.com