Still got issues on 2007 E class estate rear self levelling air suspension.

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Well when the car went down at the back with your wife driving the ride height sensor must be right at the top of culprits to cause this,it is just a potentiometer ,if that is damaged or has moved then ride height will go up or down,as you say it is 50 miles to a indy,have a ring around local garages one may have a star ,I found a local garage which quiet frankly I would never have used but was told they had a star and knew how to use it.

Thanks Zipdip. I did renew the arm a couple of years ago but not the electronic box it attaches to. I’ll plan on jacking the car back up and sit it on ramps while I remove the arm from the antiroll bar and see if anything operates/ moves. I presume the engine needs to be running?



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Well cannot say I am a expert of the estate version with air only at the back,but lets face it if you put 10 bags of cement in the back,the car will compensate only by that sensor telling the ECU that the pump needs to put more air into the rear air bags,on my S the pump fed a steel air tank from which the suspension demanded air,which the pump replaced,the Star diagnostics are amazing I watched as it checked my pump 5 times by emptying the tank and seeing how long it took my pump to replace the air,my pump failed the time test 3 times out of 5 so a new pump and the small air leak repaired,hope you find the cure for your car.
 
Well cannot say I am a expert of the estate version with air only at the back,but lets face it if you put 10 bags of cement in the back,the car will compensate only by that sensor telling the ECU that the pump needs to put more air into the rear air bags,on my S the pump fed a steel air tank from which the suspension demanded air,which the pump replaced,the Star diagnostics are amazing I watched as it checked my pump 5 times by emptying the tank and seeing how long it took my pump to replace the air,my pump failed the time test 3 times out of 5 so a new pump and the small air leak repaired,hope you find the cure for your car.

I’m away from home at the moment with the Mercedes partially dismantled in my workshop. When I get back I’ll jack her up properly and put her back wheels on ramps to emulate weight and start seeing if and what works. If and when I get her roadworthy my first port of call will be to find someone with Star


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A faulty compressor wouldn't cause the air springs to deflate.

The release valve for the deflation is built into the air spring. They will only deflate if the sensor triggers them to, or they leak.

In fact, to get my original air springs off I had to drill a hole in each of them to get them deflated enough to remove! Even after disconnecting the air hose they won't let any air out.

I'd start by checking jumping the compressor relay to make sure that works. When it pumps back up you can investigate the level sensor and whether there are any leaks.

For what it's worth, I had similar symptoms from the new one I installed incorrectly. The car drove fine for a couple of weeks then the spring deflated.

Hopefully it will just be the connector between the level sensor and the ARB though.

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Any idea which relay is the one for the compressor?



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Cheers Millo,

Many thanks again.

I had two hours spare today so I started with the ride height sensor/adjuster above the rear axle. This because of the ride height being a bit low. The car had lost no height/ air during the three days I was away.
Jacked it up at the rear, but put the rear wheels on ramps so the cars weight was on them. Then loosened the clamp attaching the sensors arm and tried it one way and then the other to encourage the car to lift a bit more at the rear. Nothing much happened except for a red warning message on the dash saying “car too low, stop car”. This when the clamp was swivelled in one direction giving the car the impression it was lower than it actually was.
However, it disappointedly didn’t activate any increase in ride height. So, not sure if this indicates the potentiometer/sensor is knackered or something else is amiss.



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Cheers Millo,

Many thanks again.

I had two hours spare today so I started with the ride height sensor/adjuster above the rear axle. This because of the ride height being a bit low. The car had lost no height/ air during the three days I was away.
Jacked it up at the rear, but put the rear wheels on ramps so the cars weight was on them. Then loosened the clamp attaching the sensors arm and tried it one way and then the other to encourage the car to lift a bit more at the rear. Nothing much happened except for a red warning message on the dash saying “car too low, stop car”. This when the clamp was swivelled in one direction giving the car the impression it was lower than it actually was.
However, it disappointedly didn’t activate any increase in ride height. So, not sure if this indicates the potentiometer/sensor is knackered or something else is amiss.



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Went to Arnold Clark Mercedes today and got a new ride height sensor and a relay. £129 odd quid. Fitted the ride height adjuster and bugger all difference. I did hear the compressor initially start and run and then cut off before ride height was fully up. It’s drivable without any warning messages but well down at the rear and relatively high at the front.
Looks like a new compressor next.
Mercedes 2203200104
Mercedes 2113200304
Mercedes 220 320 01 04
Mercedes 211 320 03 04
Wabco 8840103590



Fit For the Following Vehicles:

Mercedes-Benz S-Class W220 (1998-2006)
MAYBACH 240 2002-
Mercedes W220 S-Class 1998-2005
Mercedes W211 E-Class 2002-2008
Mercedes S211 E-Class Estate 2003-2009
Mercedes C219 CLS-Class 2004-2010

Joke is it’s cheaper than the sensor I’ve just fitted.

That will be just about everything changed. The one thing Arnold Clark didn’t have in stock was the compressor’s filter[emoji848]




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I got a cheapo aftermarket compressor for £99 from eBay which works fine. I've since rebuilt the original mb one just in case it's needed later. The rebuild job is really very easy. Loads of vids on YouTube showing the job.

MERCEDES E S CLASS W220 W211 C219 WABCO AIR SUSPENSION COMPRESSOR HEAD CYLINDER | eBay

FOR LAND ROVER DISCOVERY 2 RANGE L322 WABCO AIR SUSPENSION COMPRESSOR REPAIR KIT | eBay

These are the parts I used for the rebuild.

The dessicant can just be dried out in the oven and refitted.

After rebuild the old compressor tests fine and produces plenty of pressure.

The aftermarket one has been on the car for over a year with no issues.

Watching with interest to see what the end result is.

And to think I thought it was a pita replacing the spheres on my old w124. I thought air suspension would be a step up....how wrong I was!
 
I got a cheapo aftermarket compressor for £99 from eBay which works fine. I've since rebuilt the original mb one just in case it's needed later. The rebuild job is really very easy. Loads of vids on YouTube showing the job.

MERCEDES E S CLASS W220 W211 C219 WABCO AIR SUSPENSION COMPRESSOR HEAD CYLINDER | eBay

FOR LAND ROVER DISCOVERY 2 RANGE L322 WABCO AIR SUSPENSION COMPRESSOR REPAIR KIT | eBay

These are the parts I used for the rebuild.

The dessicant can just be dried out in the oven and refitted.

After rebuild the old compressor tests fine and produces plenty of pressure.

The aftermarket one has been on the car for over a year with no issues.

Watching with interest to see what the end result is.

And to think I thought it was a pita replacing the spheres on my old w124. I thought air suspension would be a step up....how wrong I was!

Cheers again.

The expensive sensor at the back had little to no resistance on the arm so think it was better replaced anyway.

I have just bought the £98 aftermarket compressor too, and was planning on doing the same as yourself by using Bagpiping Andy. Think I bought a repair kit from him for my RR L322 a few years ago.


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The relay for the compressor is in the fuse box under the bonnet. In my car its right at the back, closest to the windscreen and the outside of the car. Genuine mb ones are green and are about £13 from the dealer.

You can test the compressor by jumping the sockets for pins 87 and 30 which should turn the compressor on even without the ignition on.

Compressors are straight forward to rebuild. An eBay seller called bagpipingandy sells a good kit for about £20. Check the cylinder head for scoring as that may need to be replaced if it's heavily scored and can be bought from eBay for about £30.

It's also worth replacing the dessicant material in the compressor, and definitely replace the filter.

Perfectly serviceable aftermarket compressors are available on eBay for about £100 though.

If you do take the compressor out, be very careful refitting it.

The frame it mounts to is quite flimsy and its easy to snap the studs the compressor fits onto.

I've done that as well.

The revised part is a lot beefier, but needs new fitting kits for the compressor , so the new frame and fitting kit came to £91 from the dealer.

You have to take the front bumper off and remove the passenger side headlight to fit it . That was a fun day. Not difficult jobs, but a pita none the less.

Ok, just taken the compressor off. No dramas and took about half an hour from driving the car back into the workshop.
Jacked up, NSF wheel off, inner front splash guard off, the two front most lower trays removed, two electrical connections and air feed pipe removed at filter. Air feed pipe undone. Three compressor mounting bolts undone and out[emoji1303]


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Ok, just taken the compressor off. No dramas and took about half an hour from driving the car back into the workshop.
Jacked up, NSF wheel off, inner front splash guard off, the two front most lower trays removed, two electrical connections and air feed pipe removed at filter. Air feed pipe undone. Three compressor mounting bolts undone and out[emoji1303]


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Had another half hour this afternoon so thought it worthwhile to check out the original compressor. Of course I was hoping for an obvious fault such as wear on the barrel or the piston ring. However, no apparent wear that I can feel or see. A little grubby under where the barrel seats and a little mucky near the valve, but otherwise looks okay. Springs all intact.
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I’ll just have to hope there’s something else going on and that a replacement compressor sorts it out......

Millo, do you remember if the replacement compressor come complete, or were there items to swap over?


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It comes complete, so nothing to swap over from the original compressor.

Is there any scoring or marks on the inside surface of the cylinder head? it looks ok. mine was trashed as the filter probably hadn't been changed in 15 years.

If you remove the internal spring on the old compressor, you'll be able to get the desiccant out, and from the look of that compressor I'm guessing it'll be soaking wet in there. That's probably been impeding air flow to the springs.

It might even be worth drying it all out and connecting it back up without fitting it to the car just to see if it will pump the suspension up.

I nearly bought one of these:

Schrader Valve Tyre Valve to 4MM Air Line Hose Adaptor/Connector | eBay

so I could pump up the suspension from an external compressor.......In fact, i still might!
 
It comes complete, so nothing to swap over from the original compressor.

Is there any scoring or marks on the inside surface of the cylinder head? it looks ok. mine was trashed as the filter probably hadn't been changed in 15 years.

If you remove the internal spring on the old compressor, you'll be able to get the desiccant out, and from the look of that compressor I'm guessing it'll be soaking wet in there. That's probably been impeding air flow to the springs.

It might even be worth drying it all out and connecting it back up without fitting it to the car just to see if it will pump the suspension up.

I nearly bought one of these:

Schrader Valve Tyre Valve to 4MM Air Line Hose Adaptor/Connector | eBay

so I could pump up the suspension from an external compressor.......In fact, i still might!


That’s good the new replacement comes complete. I wouldn’t want to swap over a dodgy valve and misdiagnose yet another part/fault.

No lips or scoring within the barrel of the head. I do understand that the piston ring itself can wear to a taper due to the poor compromise of necessary angle of the con rod, but it doesn’t look worn at all.

Good point about the desiccant. If and when this matter is concluded, I’ll pull the original compressor fully apart. After all, I’d like to know for sure what the final issue is for sure.

I haven’t looked at your link yet but suspect it is so you can remotely pump up your air bags without having to rely on so many in-built car components. Good idea, and if this doesn’t cure it I may we’ll consider it!

When I disconnected the small diameter air feed pipe from the compressor there was no release of air and both air bags held their pressure. With the bags, height sensor and relay being renewed it makes me think that it can only be a compressor issue remaining.
I’ve checked the airlines for leaks, and all the multipin electrical connections which appear as new. So unless there’s a hidden damaged wire I can only imagine it’s a sub standard compressor related issue.

Probably won’t get the new compressor until later this week, but will post on progress with a picture or two once the compressor is fitted [emoji1303]




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While the compressor is out it's worth checking the wiring between the relay and the compressor .

I've read on the us forums that a lot of people have found scuffed wires around the multiplug that connector that fits onto the compressor.

A quick visual check, and check continuity from the relay base to the multiplug terminal, and also check the other terminal has a good ground.

I just crimped a spade connector onto a long bit of wire and inserted it into the relay base socket and put a multimeter between that and the multiplug.

While you're in there, it's also worth checking all the other sockets on the relay base have good connections to either 12v positive and ground

Should only take 10 mins with a multimeter to eliminate any potential issues.
 
While the compressor is out it's worth checking the wiring between the relay and the compressor .

I've read on the us forums that a lot of people have found scuffed wires around the multiplug that connector that fits onto the compressor.

A quick visual check, and check continuity from the relay base to the multiplug terminal, and also check the other terminal has a good ground.

I just crimped a spade connector onto a long bit of wire and inserted it into the relay base socket and put a multimeter between that and the multiplug.

While you're in there, it's also worth checking all the other sockets on the relay base have good connections to either 12v positive and ground

Should only take 10 mins with a multimeter to eliminate any potential issues.

All good points thank you. I actually bought that schrader adapter. The seller obviously sees you’ve checked it out as two hours later he’s offering it at £7.95[emoji3]
Hopefully by buying it I won’t need it, but it would be very interesting to lead it into the bonnet area, pump up the suspension and see how long it stays up without needing a refill. After all if all I’m carrying is a couple of Retrievers or nothing the height difference between being dog loaded and empty will be very little.


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All good points thank you. I actually bought that schrader adapter. The seller obviously sees you’ve checked it out as two hours later he’s offering it at £7.95[emoji3]
Hopefully by buying it I won’t need it, but it would be very interesting to lead it into the bonnet area, pump up the suspension and see how long it stays up without needing a refill. After all if all I’m carrying is a couple of Retrievers or nothing the height difference between being dog loaded and empty will be very little.


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Ok, compressor came today so have just fitted it along with the new relay and filter. Hardest part was refitting the holder for the relay which decided to pop out. I haven’t refitted the covers yet or driven it but did fire it up to check the compressor was operating. It came on for about 20 seconds and cut out. The car lifted at the rear slightly so the tyres are just clear of the arches. Hopefully when everything is back in place and driven it will come up another inch. I’ll report back after my Phisio and dental appointments.


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Ok, compressor came today so have just fitted it along with the new relay and filter. Hardest part was refitting the holder for the relay which decided to pop out. I haven’t refitted the covers yet or driven it but did fire it up to check the compressor was operating. It came on for about 20 seconds and cut out. The car lifted at the rear slightly so the tyres are just clear of the arches. Hopefully when everything is back in place and driven it will come up another inch. I’ll report back after my Phisio and dental appointments.


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Well got it all back together and drove it out of the workshop. Compressor runs on initial start up and cuts out after a couple of minutes. However, the ride height is still too low........if it were happy with the ride height I don’t think the compressor should be running on each engine start up.

Not sure what the issue is but I’m now wondering if it could be that the valves that are screwed into the top of each airbag might not be holding adequate pressure. I did use new seals on the plastic stems but these are valves swapped over from the original air bags, as the bags came without new valves.....
I can’t really hear if they’re leaking with the engine running and they’re too hidden (under the top air bag mounts) to see if soapy water shows if they’re continually allowing air to leak after a set pressure.

I’m now starting to wonder if I should have scrapped the car as this is getting a bit ridiculous.
Anyone know what these valves are called and where I might source them if required?


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Is your newly fitted ride height lever, the one thats on the rear axle, adjusted to the correct length. Mine snapped and when I replaced it wasn't high enough so I had to adjust the length by trial and error.
 

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