Originally Posted by bagpipingandy

that lager 8mm plastric hose in that video is a red herring, it is the output hose, this is where air comes out when the car lowers, the N111 solenoid valve on the compressor opens along with the valve block valves and lets air vent back through this pipe, i assume to silence it, a hole in it will potentially let dirt into the compressors intake, but not reduce the pressure.

Originally Posted by Redline21

Thanks for all the info. I pulled the compressor out last night and direct wired it to the battery. It is pushing air out, but it certainly isn't a ton of air, or at least there isn't a lot of pressure to it. Unfortunately I don't know how that compares to what a good compressor would put out. The odd thing here is that when it is working the compressor raises the car just fine. However I have notice fluctuations in the tone of the compressor. It will occasionally change to a deeper tone, like it is under a heavy load. Usually only for a second or two. In any case, most signs do seem to point to a compressor issue. I am about to pull the trigger on ordering one.

I did stumble upon this:

2001 Mercedes S430 Suspension Airmatic Pump Leak Problem - YouTube

When I was bench testing the compressor last night I found that it was indeed leaking at the curved end of this hose. I sealed it up with some RTV sealer but after putting things back together I still have no lift. I'm wondering if I have two problems here, intermittent no-lift and a compressor leak that is blowing fuses. In which case hopefully I just fixed the compressor leak and won't blow any more fuses if I can get the lift issue sorted out.

When the system vents air, where does it release it through? The pneumatic valve on the compressor?

Originally Posted by PetrolBear

It does not seem an easy case!
Just a quick feedback - I hope you will be able to solve this soon.

Possible problems - you schould check them out systematically! :

- LCM module damaged due to overheating of some components. Reason is the too often operation of the compressor during the decades It can go wrong after 10-11 years, so it is possible. The module should be able to communicate via OBD without interruptions. it is important. If you "loose it" sometimes, but the power positive (terminal 30) is OK, it means the module is dying.
- Magnet valve block. I don"t think so! They go wrong rarely (except if moisture comes into the airlines)
- electrical wiring. Rarely goes wrong, but check for the connections at the wheel level sensors!
- Wheel level sensors. Highly possible! Check for good mechanical ability and clean signals. In case the transmit a false signal, it can lead the LCM module to adjust false level positions - believe it or not, even from a bigger bump (reason: mechanical pinching, bad signal) The turning discs can be rusty after 8-10 years. Cleaning usually solves the problem. Note: the level can be measured even if only one level sensor per axle is in operation. If both fail, the LCM module looses the car's position.
- N111. Rarely goes wrong. Can be replaced with the compressor as I recall (it sits on it)
- Error code G291? If yes, do not change the valve block autmatically! It means that there is insufficient pressure in the alu tank -> compressor is weak or there is serious leak
- Plastic pipes. Rarely go wrong! Assembly failure happens sometimes..
- Compressor. Yes, you changed the o-ring but you need to measure the produced pressure in the alu tank ( via OBD again). In case the compressor cannot reach 11 bar, throw it out. I think your compressor is dying. Blowing the 40A fuse means it draws too much current. It is the sign that a magnet has been released on the electric motor and causes a partial short circuit (inside!). Take a look at the onboard voltage meter, in case you hear a change in the compressor's noise. If it comes to a deeper, slows down, you might see that the onboard voltage drop even to 12,6 volts, temporarily -> partial short in the compressor.
- The relay of the compressor can also make problems but that is not so common. In case you buy a new compressor, you should change the relay switch as well. Highly recommended.
- overnight parking test in jack mode, at level 2 and level 1. Measure the distance at each wheel (evening, morning) Temperature drift may occur, but that take approx the same 1/10, 1/8 inch loss.

The best way to check all these, you schould ask the shop to make LIVE data via the OBD panel, with a notebook in the hand, with the (e.g.) VCDS software. That means that you drive the car, and he tests the functions. All errors can be measured this way, such as: loosing air at any corners (on bumpy road, levels...) readiness of the aluminum tank up to 16,5 bar (or less , due to bad compressor?) , you can get the error codes and even, the operational situation of the compressor! I highly recommend this.

Originally Posted by todd g

good video and great tip on the Hose upgrade!

1) Not sure that this applies to the Allroad Compressors though...looks like the Allroad Compressors already include this type of design...can anyone confirm?

2)) only thing that the video didn't mention is whether or not the right side cylinder area needs to have a different configuration (be changed out) when using the new revised hose or whether it is the same piece as before. Can anyone confirm?

it looks like no change is needed, except for the MBZ part number A 220 327 00 00

3) does the OEM connecting hose reach to the new connection location on the right side or did that need to be lengthened?

Originally Posted by bagpipingandy

remove the 2 torx screws holding the N111 valve in, and remove valve, plunger and spring, it is possible the spring broke or it is rusted stuck, this would cause all air to just be sent out the large plastic pipe

if you dont decide to repair it "todd g" a few posts down is needing a compressor motor

regards

Andy

Originally Posted by Redline21

I pulled N111 apart the first time I had the compressor out. The spring was not broken but there was indeed some rust in there. Not sure that there was enough to keep it from functioning, but who knows. I'll reach out to todd g as I don't really want to waste a lot of time trying to rebuild mine.