Air suspension compressor

Hi Guys,

I know this is a popular problem but I require a definitive answer if possible. Today my 99 TD5 rear suspension dropped to the stops after towing my friends boat home.

Initially there appeared to be no problem when the engine was off and parked on the drive the truck stayed at normal level. When i came to use the truck again and started it up I heard a strange noise from the compressor, the truck was at normal height at this point. I drove the truck but on my return and parking up with the engine stopped the suspension dropped. I started the truck expecting it to pump up, but nothing and the compressor is not running.

My question is, can anything prevent the compressor from running or if it detects the suspension is low would it run regardless. I suspect the compressor may have failed but need to cover all the options first.

Cheers,

Jez..

The surest way to check the compressor and connected valves is to disconnect the electric plugs from the assy and give direct feed to them with an improvised wiring. Connector disposals in RAVE. U can do it for each part a time or you have to manage to feed the two air supply valves and the compressor at the same time and if there is no prob then the car will rise. Take care to stop feeding it if it's high enough as to not overinflate the bags. This way, if everything is disconnected when it's up it must stay up for days if there's no leak along the system. The air could leave the system through a defect valve too not just through a leaky airspring.

Hi Jez
I just had a recent problem with mine, it was a seized ride height sensor.
Put the Nanocom on it & there was intermittent signal from the O/S/R.
If there is any fault logged in the SLS ecu, the compressor won't fire up.
So it might be worth checking the sensors & plugs.

Andy

Mine did the same. Was a faulty ride height sensor. Also, forgive me for stating the obvious... but have you checked the fuses .

Hi Guys,

Firstly thanks for you suggestions and advice. The story does have a happy ending though.

Having left the truck overnight with the intention of stripping off the compressor the following morning, I went out to the truck, started it and up she went as normal. Has been a couple of days now and no further problems Having read the replies though I am going to order 2 new ride height sensors just to be certain.

Thanks again for all the help,

Much relieved

Jez..

The ride height sensors I doubt are the problem. Inspect them closley for cracks for sure and replace if they are. they are easily tested. There is a high chance that your compressor will develop an intermediate fault and that will be down to water ingrerss in the motor. This combined with oxidation from the armature forms a grinding paste which will wear the brushes on the motor to nothing in a matter of a just couple of months. once the brushes are worn to this degree you get intermediate failure of the compressor motor.
have a read of this: http://www.landyzone.co.uk/lz/f38/disco-ii-air-suspension-definitive-guide-61211.html

also if the doors are open the compressor wont work .

Thanks battenberg,

great information and a fantastic write up.

Question....can the compressor brushes be replaced or is it a new compressor?

Cheers,

Jez..

braelab said:

Thanks battenberg,

great information and a fantastic write up.

Question....can the compressor brushes be replaced or is it a new compressor?

Cheers,

Jez..

Click to expand...

Hi Jez, as over 95% of all air suspension problems are down to leaking air springs, it might be a good idea to check them.

The way to do it is: with the engine running, the doors and bonnet closed, reach in via the drivers door window to push the offroad mode button to jack up the rear suspension. Then spray the air springs with soapy water and watch for bubbles. They usually leak around where they fold over.

Air springs made of rubber are normally considered to be service items and to ensure reliability should be replaced every 3-5yrs along with the ride height sensors. Replace in pairs always.

Good luck

Dave

Hi Dave,

Thanks for this, did the leak check the instant the suspension came back up, thoroughly checked around the bags and pipework but nothing found. Beginning to think battenberg may be right with the intermittent fault on the compressor.

Thanks mate,

Jez..

braelab said:

Hi Dave,

Thanks for this, did the leak check the instant the suspension came back up, thoroughly checked around the bags and pipework but nothing found. Beginning to think battenberg may be right with the intermittent fault on the compressor.

Thanks mate,

Jez..

Click to expand...

just take into account that the compressor has nothing to do with the fact that the suspension drops over night..... if no leak the car must stay on level for days.

braelab said:

Hi Dave,

Thanks for this, did the leak check the instant the suspension came back up, thoroughly checked around the bags and pipework but nothing found. Beginning to think battenberg may be right with the intermittent fault on the compressor.

Thanks mate,

Jez..

Click to expand...

make you you check them in extended mode as the leaks are normally wer the bag folds at the bottom.Mine used to drop over night did the soapy water test no leaks to be seen.the law of sod everytime i looked at it the thing stayed up .After months changed bag s no props since

If you need Air Spring can get it for half price from USA look on US ebay.

Cheers Guys,

Since the initial problem the old girl has stayed up with no issue.

Will continue to monitor and keep you informed.

More worryingly got her to MOT tomorrow fingers crossed

Jez..

Well she did it she passed....one happy bunny