R129 ADS Oil replacement?

[dickchailey]

With some time to spare over the hols I was browsing various mercedes forums and came across a posting about the need to replace the oil in the ADS system following failure of the spheres. The claim was that the nitrogen from the faulty sphere would be disolved in the oil and allow the fluid to compress giving a damping effect.
I have never come across this claim and would have thought the nitrogen would come out with a few raise and lower cycles when some of the oil is returned to the tank. I have however noticed that my suspension takes much longer to raise since the spheres were replaced.
Any experts with an view?

 

[jaymanek]

Doubt its down to the oil... Pretty easy to do a change though, simply run the car and disconnect the hose at the filler bottle, let the old oil pour into a container and add fresh oil into the reservoir... A couple of litres will have the whole system flushed.

 

[dickchailey]

Thanks. Would this flush the oil beyond the valve or would it be better to flush at the two drain connections? The posting gives the impression that the nitrogen contaminated oil would not be changed unless the whole 9 litres was replaced.

 

[jaymanek]

I only have experience of the self levelling on W126, W124 etc... I have never done a flush on a R129 with ADS.
I didnt realise that it has 9L, that sounds a lot, where did you get that figure from?!

If you are really concerned I would change the spheres, you can get them from Euro Car parts for around £70-80 last time I got some.