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Discussion Starter #1
Hi
I replaced the oringinal merc air suspension compressor with a new V Klasse Kompressor in June 2007. After this I noticed that the new compressor always released air through the blow off valve when the engine was switched off. I assumed this was to return the vehicle to an unloaded level setting. However it would, if left long enough, eventually lose all its air and upon restarting, have to reinflate the suspension from empty. This also happens if you put the suspension in a hold position by holding the suspension dashboard switch down when switching off the engine, although it takes much longer. Is this normal for a V Klasse Kompressor ? If not should I have had the suspension recalibrated by a Mercedes dealership not something I am keen on as in Yorkshire Uk money is well cared for! Any input welcome.

Thanks
 

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Merc know 'sh*tall' about the V Class air suspension......they are experts at 'replacing' the unit and fleecing the customer! Send an email query to V-Klasse and they will advise you if your case is a problem or not and how to rectify! You need to ensure that the air pipes are properly attached and secured to the solenoid valves, even a slight misalignment on fitting will cause the gradual 'leak' when vehicle is not run for a day or so. Mine has the same problem but with the original unit - I changed the solenoid valves a while ago but did not attach the pipes securely thus the 'slump' overnight. Not really bothered as I only drive it once in a bluemoon! Will sort it out when we have the long, hot sunny days!
 

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Discussion Starter #3
Thanks for the info Punjabi. I must admit when I fitted the new compressor I did not retest for air seepage as it inflated the suspension straight away. I will spray with leak tester when it stops raining. When the fault first (losing air and compressor overworking) appeared I had it checked at the Merc main agents who in their wisdom advised a new compressor two new air bellows and if that did not work take a look at the control box at a cost of £2000.00!!!!
I asked to speak to the fitter and they fetched him, he confirmed this stupid approach to the problem and offered to take me around to the rear compound for the vehicle as they would no longer drive as it was deemed unsafe. However , bless him, he told me that he had advised changing o/s rear bellow only as it was showing a air weep on the diagnostic check and that to advise me that the compressors had a limited life span due to the mounting position but at just short of a £1000 each dont fix if it aint broken. He had been told to confirm the service guys advice but was unhappy with the situation and therefore the extended site tour to fetch my V class. When I told him the price he was to say the least stunned and told me the air bellows were approx £80.00 each and explained how to fit it also that they are prone to leaks from where they are seated due to the metal rusting and flakes of rust getting trapped between the bag and its seat. The failure being accelerated by constant deflating and reflating causing the bellow to reposition very slightly each time also that they where not allowed to strip clean or repair the compressors he said the whole job ie 2 bellows and compressor would have taken him less than an hour. I changed the compressor (after stripping and examining and deciding that £320 delivered from Germany for a new V KLass Kompressor was a bargain ) in 20 mins and an HGV fitter who used to work for me collected the van changed the air bellow and returned it to me in less than an hour for £100 including parts. Mercedes agents are just overpricing manipulating morons!
 

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You mind telling me where you got the compressor from that cheap? My air suspension doesn't work anymore, since the battery went flat (yet again!), as something keeps on draining it, it doesn't last more than 2 days standing! There's no air in the suspension now, so it's on the rubbers. Have recharged the battery but when I keep the air suspension button pressed (whilst driving over 10mph), it flashes really fast. This usually happened when the fuse was blown, but I've checked all the fuses under the passenger seat and they're all OK. Now I've heard that the lights flashes fast as the car's too high or low, (in my case low), so could this be why it's not inflating? And is there any remedy for this? But I guess if you've changed your compressor then your V Class would have been on its rubbers as well, so this can't be the problem! So have run out of ideas and was wondering where to get a new (cheap) compressor! So any help would be appreciated. :)
 

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Discussion Starter #5 (Edited)
V-Klasse-Presser.de (web site)

No problem firstly avoid driving with suspension deflated it will eventually shag the air bellows for the reason I stated in my post. The following link will take to the forum page I found the most useful info if the link does not work search for Klasse Presser (key words) in posts made by ralfs then click the third post.

http://www.benzworld.org/forums/v-class/1271464-v-class-air-suspension-phew.html?highlight=klasse+presser

The next link should take you to the above site to the kompressor I bought remember euro exchange a lot lower this year total price I paid was 462 euro delivered exchange rate then 1.45 actual unit price 435 euro I suspect cost in sterling to be £370/380 now delivered their price is the same now as when I bought one last year. If the link does not work search google for the web page in the title and click for translated version.

Translated version of http://www.v-klasse-presser.de/


Last thing start the vehicle warning light should be flashing hold down the suspension switch for approx 2/3 seconds release light might go out and inflate. Worked for a few times untill new compressor fitted and believe me it is very easy to fit. Any questions feel free to ask. Air supension is much better than springs I ran HGVs light vans etc for twenty years well worth the effort to fix.

Good Luck
 

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Thanks for the quick reply.

I reconnected the battery (I have to leave the black lead disconnected nowadays as otherwise it will drain the battery in 1-2 days!), started the vehicle, the warning light stays permanently lit and is not flashing. I kept the button pressed for a few seconds but the warning light flashes very fast until I let go of the button, whereby it stays permantly lit again. Is there any way to actually check the compressor by putting 12 volts on it, to see if it works? I've *heard* that the compressor is next to the rear nearside wheel. I had a look, but didn't really know what I was looking for, I saw a little "box" thing on the edge of the nearside rear of the vehicle, which feeds onto a big tank(?) under the car, I assume that I need to remove this box cover and the compressor will be inside? Are there any instructions on how to do this or is it just a few bolts that need undoing? There's also a *thing* under the vehicle but in the middle of the vehicle, not sure if that's the compressor or what?

Thanks for the links and your help. Will do my research now in case it is the compressor thats faulty.
 

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Discussion Starter #7
The compressor is mounted under n/s floor 300mm behind the passenger door
as I remember there are three plug type connectors two of which power the solenoids that allow air to each of the rear bellows as required.The third one powers the compressor from the vehicle power source brown (earth) blue and black (postive) to the compressor these should be black (earth) and red (positive).If you unplug this one and use a 12volt circuit test light across brown and blue black, with the ignition on, and the bulb lights the compressor is receiving power because the self level valves at the rear will be calling for air. If you put a 12 volt supply to the black and red when unplugged the compressor should run.Point to note the plug requires a fair amount of pressure to unplug due to it having a green rubber seal into to prevent water getting in. Also there are two air pipes that go from here to the air bellows at the rear one blue one yellow so you will know if you are looking at the correct thing. Important any action you take is at your own risk I have just tested this on mine and both methods work but of course mine is working any way. If you jack the vehicle up to do this be very careful if the compressor kicks in the vehicle height will alter, check the feed first. I add these warnings because I have seen HGV fitters do some very stupid things in my time!!

If not sure ask first please.
 

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Hi there

I've (finally) managed to find and test the compressor. I put 12 volts to it using a jump starter and I hear a very slight "click" noise once and that's it! I assume this means that the compressor's had it?

The next step is to remove it. I noticed that it's fitted to some sort of bracket and I saw that there's 4 bolts holding this bracket to the body. 2 of the bolts hold it to the underside of the body and the other 2 bolts(?) are attached to the side of the van, the skirts, if yo know what I mean. Are these the correct bolts to remove and do I need to remove these or can I just get the compressor off somehow, without removing this bracket? These 2 bolts that fix the bracket to the side of the van, I can't see how they would come off, as they're round, whereas the bolts in the middle of the van are proper bolts and can be undone with a spanner. Do you need a special tool to remove the bolts that attach the bracket to the side of the van, as they're not screws and don't look like bolts either, as they're a "round" shape and not hexagonal? And if these are the 4 bolts to remove, is that it, before the compressor bracket can be removed or is there anything else that I need to know?

Or do I leave the bracket where it is, and somehow just remove the compressor from the bracket?

Sorry if you don't understand this, but I've tried to explain it as best as I could :) If anything's unclear, I can probably try and take some pictures to show you what I mean.

Thanks for all your help, much appreciated.
 

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Discussion Starter #9
V class compressor

Hi
The two bolts that are and look like bolts undo, the other two bolts to the skirt are not bolts but locating pegs. Unplug the electrical connections and the air pipes (with no air in the system ) as far as I can remember these pipes have small collars on that you push towards the solenoid then pull on the pipe to release, remove bolts and the complete unit plus protective guard will waggle free from the skirt. The compressor then unbolts from the guard.Because its clicking it may be repairable at a compressor specialist. I have a vague recollection of dismantling mine and noting a relay/solenoid somewhere. Sorry that I cannot be more specific, I have dismantled so many things to repair over the years computers to HGVs I simply cannot remember the details. However I do remember thinking at the time after looking at the whole things condition after six years of use it was junk and fitted the new one from V-Klasse.

If in doubt please ask
 

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Discussion Starter #11
V Class compressor

Hi
Remove the complete unit, two bolts two pipes unplug electrics, it is an easy job to do, make sure you support the vehicle correctly if jacking it up. There is also a black inlet pipe that goes to the skirt which needs to be pulled out.

Good luck
 
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