Air compessor

I have heard of cases where the air suspension has dropped too far and the compressor won't start up again. That usually happens when the rear end has dropped and been left in that condition for some time. To cheat the SLABS ECU the usual trick is to jack the rear end of the bodywork say from under the towbar a small amount and the system often them kicks back into life.
However, since you say that you've changed the fuse to the circuit twice, then I'd be inclined to believe you have a wiring fault rather than a straight fault on the compressor, but a major short circuit fault in there mustn't be ruled out.

There are those who will say that the air suspension is the work of the devil, but quite frankly it's a good system which like everything else on a Disco must be looked after.
After all, why would you want to change a rubber tube full of compressed air for something made of steel?
That's going to really screw up the wheels and do nothing for the steering, braking or handling!

brian47 said:

I have heard of cases where the air suspension has dropped too far and the compressor won't start up again. To cheat the SLABS ECU the usual trick is to jack the rear end of the bodywork say from under the towbar a small amount and the system often them kicks back into life.
However, since you say that you've changed the fuse to the circuit twice, then I'd be inclined to believe you have a wiring fault rather than a straight fault on the compressor, but a major short circuit fault in there mustn't be ruled out.

There are those who will say that the air suspension is the work of the devil, but quite frankly it's a good system which like everything else on a Disco must be looked after.
After all, why would you want to change a rubber tube full of compressed air for something made of steel?
That's going to really screw up the wheels and do nothing for the steering, braking or handling!

Click to expand...

Interesting and good to now about jacking up the rear of the car. I agree fully with the maintenance side(although on more modern cars it can be a major undertaking) preventative maintenance(even just watching out for certain symptons) is best policy. 'Non service items' are a misnomer as is 'sealed for life' etc(not trying to open that can of worms) One of our clients spent a small fortune on a ML 320 4Matic (TWICE) because of dealer incompetence and his own ignorance(and you could say my colleague and mine too!) Two compressors(by Main stealer) and another by a more trusted family garage(that specialised in Porsche) AND two front air suspension assemblies.....quickly followed two weeks later by the rear suspension. Total cost was aroubd €16000-00 between the two garages. Then a month later the front on the S Class 320 4Matic started to act up too...That was only €1800-00 and didn't require anything other that air assembly replacement. That was 6 years ago. That car is still on the original rear suspension, had done 140,000km when I last saw/drive it and the same comoressor too..

The ML's indicator of imminent air suspension failure was the compressor working too much, even when driving....despite warnings to our clients they just continued driving it......money does not guarantee a normal level of common sense!

Thanks everyone for all your help, i'm going to have a proper look over the weekend and will post later to let you know what happened

Just wanted to say thanks for all the help everyone, it was the compressor that had failed.
The local garage said they could supply and fit it for around £450 so I got a used compressor from ebay for £60 and spent 2 hours this morning fitting it and so far so good, I did have to jack up the rear before it started to kick in but it seems to be ok at the moment.