Airmatic pump
 

I've been told by the shop that my compressor is not distributing air correctly(something like that) and thats why my back is really high, they said I need to change air compressor 400$, one of the hoses is leaking 50$, change relay 50$, and change valve block assembly 300$ plus labor, so total 1200$, they said valve block assembly 99% its needed to be changed, but still its better to replace it right now, cause it will cost more later, but Im not planning on keeping this car for more then few weeks. I also had top struts repaired with repair kit. Do I really need to replace valve block assembly? will changing relay fix the problem or new pump is the only option? The car sinks down(front) a little bit after few days and when I start it it comes back up, but the back still at the same spot, so the pump is working.

RE: Airmatic pump
 

Hi Gixxer,

The advice you have been given appears to be CONTRADICTORY. The air compressor pump doesn't distribute the air. Distribution is determined thru a valve block.

Airmatic does go down after a few days. this is normal. It all depends on how long it takes to get itself up again. Basically it;s a matter of how big is the leak (some leak occurs even on a new system) vs the capacity of the pump.

Likewise why do you need a new pump. Its obviously working OK. there is a pressure sensor screwed into the pump which could be reading incorrectly but this will be covered by the action that I suggest.

Anyway the car pumps itself up and your problem is one of the the rear end trim height being TOO HIGH, not too low.

The two key suspects here are.

1. The Rear Trim Height data stored in the Airmatic ECU may be incorrect / corrupted since you have had previous trouble trouble with LOW trim height previously..

2. The rear trim height sensor arm has been damaged / bent / reset incorrectly.

Maybe somebody has messed around with either the sensors or the data values in the ECU.

It is possible that the distribution valve to the rear struts has seized and that the rear end is HIGH since the problem occurred when you had a heavy load in the rear (luggage or passengers) which has subsequently been removed.

Best course of action is to get the vehicle to a main dealer with SDS STAR diagnostics and get the ECU values checked out / reset. Whilst this is being done the diagnostics will also give a code pinpointing what data aspect of the system is wrong. Unfortunately main dealers often charge for this diagnostics check however this SHOULD be only circa 50 USD (Guess but this will save you a fortune should parts be changed unnecessarily!))

I make an assumption that should the FRONT or REAR SUSPENSION has been removed from the vehicle for whatever reason that the lower suspension arms have been correctly refitted / tightened at KERB condition. If not this can upset the front / rear attitude of the car. Unlikely but just in case.

Stuart

RE: Airmatic pump
 

I actually got a copy from that shop and compared to MB dealer's, at the dealership, tech said that my pump is working fine, but my air control valves not functionin properly, or could be my height sensors. and this is what that shop said " the technician tested the airmatic suspension system and found the airmatic pressure release valve does not function properly. also found line between compressor and valve leaks. need to replace compressor and line. Also will need to install updated relay. Also recommend raplacing valve block due to high failure rate."
My car is at the dealership right now, first I told them to do the calibration, and then call me if that will not with the problem(back is too high), then we could try replacing valve block and height sensors. I think I could have damaged/bent sensors on the back, I used to have 20s on it and car was low for quite a time.

RE: Airmatic pump
 

So my advice was in line with the MB dealer?

Regards,

Stuart

RE: Airmatic pump
 

yes, he actually called me today and said that they did the calibration on my car, front got fixed, but back is still high, he said that the pressure is there so its not the pump, and the sensors looked good when tech checked it out, but he wasnt sure about it. so its probably a valve block, he wants to do more diagnoses on itbut im just tired paying all the time to just diagnose. he said to change the valve block will be around 700$, is it hard to change? is it possible to do by myself?

RE: Airmatic pump
 

IMHO it will take about an hour to change the valve block.
It all depends on how DIY competent you are whether you should tackle the job.
You will need access from under the car/
First step is to remove the panelling from under the engine (6 screws) + the cover in front of this. This will part expose the pump under the RH wheelarch.
Can't remember but I think you also need to remove the wheel arch plastic liner. (about 15 screws once the wheel is removed.) at least this will make the job easier if you are going to have to crawl under the car.
Pump removal is straight forward. Once the pump is "out of the way" you will see the valve block.
Straight forward.

HOWEVERr!
I would not put the valve block at the top of my suspect list. Near the top I agree but not top.
If the car has been on SDS this allows the trim height to be set front and rear to X inches = spec. IF the rear is high these settings MUST be wrong so why weren't they changed? IF indeed these settings were changed and the rear is still high the issue is whether the rear height can be changed by changing the setting or whether for some reason the rear trim height appears fixed and is too high. IF the answer to that altering the setting makes no difference to rear trim height then the sensor must be disconnected, damaged, bent...i.e. the correct data setting gives the wrong height. If changing the setting fails to alter the rear trim height then it iis likely the valve block that is at fault.
Strikes me the tech at the dealer didn't do the job correctly.

Finally if the guy states that the pressure relief valve is not working...how does he know this. SDS? then surely the first thing to change is the relatively inexpensive pressure valve...
HOWEVER this may only be available as part of the pump unless you can secure a used one.
Let me know how you get on.
Stuart

RE: Airmatic pump
 

thanks for the answer, as far as I understand, you're saying that I have faulty sensors? I quite didnt get the part where tech didnt do his job correctly about the settings... And how hard is it to change the pressure valve?

RE: Airmatic pump
 

snanceki, I printed out your answer and showed to the guy at the dealership, hestarted changinghis story and said that he has to talk to a technician on monday, when I was talking to him he was going in circles, solooked like he was hidding something. I wanted to find out from him how sure they were that it is valve block, since I've been told that they have high rating of failures, he said that my pump most likely needs to be changed because they have more chances failing then a valve block, but then he said that my pump is fine (that was exactly what he said),so that didnt make any sence. he also said that when tech was doing calibration, he was able to lift the front up to normal, but the back wasnt moving at all, he said that something physical was holding it, so I dont know what kind of bs is that, since when my car was sitting in my garage, I measured it every morning fow few days, at first it was 29-1/4" and after few days when I let the car run for some time it went up to 30".

RE: Airmatic pump
 

Gixxer,

The "story" now makes more sense although I suspect that there is something wrong.

So the guy who did the "calibration" couldn't get the back of the car to move but the front was fine.
So my questions would be.

have any changes been made to the suspension on this car in order to fit 20" wheels or similar. Who did the work. What did they do??
Why are you having so much trouble. You didn't answer my question as to whether you had just bought the car.

Has anybody physically looked at the back of the car to ensure that the sensors are OK?
Is this garage using SDS or some other proprietary equipment?
What codes if any is SDS showing?
Are these guys MB Airmatic trained?
Although this may appear complicated to you Gixxer this is not rocket science to a good technician and certainly not to an Airmatic trained technician. So what training has the guy who's actually working on the car got (not the reception desk guy)? Has he every worked on electronically controlled systems before? If so what has he actually done and why does he have a problem fixing the problem?
What sensor output voltage or position does SDS show?
Does this output signal change if the rear of the car is lifted slightly when connected to SDS?
What ride height have the sensors been set to?
Why did they say the Airmatic pump, relay needed to be changed?
Is the pump output pressure reading within limits?

I suspect that somebody has "fixed" the rear suspenion so as to fit wider, bigger wheels etc. Maybe they have blocked off the airlines between the valve block and the rear struts (ball bearing or similar)

Without the car and factual information I can only go on giving ideas. Can't help much more until I know exactly what has been done, why and what the remaining problem is.

The valve block could be bad but sometimes you say the car is low, other times high. The valve block failure would not give inconsistent results.

Either the data / information that I have been given is wrong or I go back to the rear sensors having been "disconnected" mechanically as the most likely cause of the problem. Must be OK electrically otherwise codes would be set...maybe codes have been set and they haven't been followed up!!

I suggest your next action before the points I list above is to determine the competency of the technicians at the place that you are taking your car to.

Who are they, who's doing the work. where is his training certificate (these should be displayed), what subject is his training ticket apply to, what date was his training certificate, who was it issued by etc etc etc......

Stuart

RE: Airmatic pump
 

I had my car for 2 years now, were driving it for little more then a year, there was no modifications done to the car to fit the wheels, the back of my car started going up after my front struts cracked and I was still driving after that, my pump worked the whole time, and then I just stopped driving it.

as for the sensors, thats one of the questions I have on the list to ask that moron, in the car histroy it says that height sensors could be messed up do to corrision, but few days ago he told me that the tech LOOKED at them and he THINKS they're ok, thats what he said.

I have my car right now at Larson Mercedes of Fife, http://www.larsonmercedes.com/