Mercedes-Benz Forum banner

1 - 20 of 25 Posts

·
Registered
2002 S430 MERCEDES BENZ
Joined
·
10 Posts
Discussion Starter #1
I have a '02 S430 and the airmatic pump is very very noisy (rattling sound and vibrations). I check it and there are 3 rubber bushing with spring on each, screws are tight, how can you get rid of the noise? Plus it always running for about less than a minute after starting in the morning but the car does not drop, it maintains the height. I check the upper part of the strut, use soap, no leak, the car does not drop at all, no messages on the dash board. Do you know where is the relay located? Can you please help me, I am new to this forum and I need help please. Thank you.
 

·
Outstanding Contributor - Always Remembered, RIP
Zotye Auto 1.5T T600 2016
Joined
·
52,804 Posts
Its evening here and I am at home, but I will take a look in WIS for you in the morning, and it does sound like the relay needs replacing, possibly the pump as well.
 

·
Registered
W210.265/2001, W220/S500/2000, Porsche 997 C2S/2006, GMC K1500/1992
Joined
·
2,157 Posts
If your air pump runs in every morning, you have a air leak in your system. In the evening, your struts has leak out the air but the air is replenished by your reserve air tank. Since the PSI is dropped in your air tank, it will triggered the air pump to refill in the morning when you start the car. One way to check your Airmatic is to raised your front wheel off the ground one by one, so your struts will extended, check the rubber bellow that covered your air struts behind your front wheels. If the bellow is off the boot, that means your system can not maintained the vacuum. that air struts is leaked but not too serious. That is exactly happened to my car last year. As soon as I resealed the front struts with two struts kits @$250 DIY, my problem goes away. My air pump run very noisy too. But since I reseal, it does not run much at all. SO I do not replace the pump or the relay. I did open up the relay and check the contact inside, it was good and has not been burn or melted. I pulled the spring backward, so this give more reset tension if the magnetic from coil is terminated. It was the Siemen relay from factory. I knew many of the post here was telling you to replace the relay to avoid over heat your pump in case of defective relay. But my logic is to eliminated the root cause of the relay being over heat. This is due to not sufficient PSI in the Air tank, going back to the problem of leaking air from the struts in the cold evening. Your leak form the struts is not serious, but it will be getting worse in time. If you do not take care of it now, you will get a bad relay and pump later. It will cost you more to replace struts, pump and relay together. The tree rubber buffer at the pump will be leak due to harden of the rubber in time and it always worked as release valve for the air system in case it is over loaded before the pump shut off by the relay. In time the buffer goes bad(harden), it can not sealed in as much PSI as required by the sensor in the Tank, air is leaking out from it to make the noise. Try tighten the screw or replace the rubber. See if this will reduce the noise level. There is also some screws attached the pump assembly to the bumper support, those will be loose after the pump operated for the mileage you drove. Check and tighten it. I wish this will help you to fix your problem. Please go to your member profile to complete your info as the vehicle you own and your location, otherwise we will not be able to help you next time. Please to post what happened to your car after you repair it, so you can share your valuable experience with this forum. I have not do anything to quiet down my pump. But what I suggested to you is got it from others post. I want to know if it works and I will do it later. Since I repair my leak in the struts, the pump hardly run anymore. When it runs occasionally as I push the raise button on the dash, the noise also quiet down. I can not reason it out.
 

·
Registered
2002 S430 MERCEDES BENZ
Joined
·
10 Posts
Discussion Starter #4
Thanks Eric, I will check the relay but the pump I think is good, my guess is, there might be some leak somewhere. Thank you so much.
 

·
Registered
2002 S430 MERCEDES BENZ
Joined
·
10 Posts
Discussion Starter #5
Thank you so much. I will do check the struts one by one and i hope that's the problem, where can I buy the seal to reseal it? What is it called? I got the rubber bushing for the pump but the springs inside the bushing, i still need to get it. I will be working on the car this Sunday and definitely, I will post it after working on the car what ever the outcome is. Thank you so much again.
 

·
Registered
W210.265/2001, W220/S500/2000, Porsche 997 C2S/2006, GMC K1500/1992
Joined
·
2,157 Posts
Struts seal are only available in your MB dealer $125 ea. Please post where you get your new rubber bushings. I wish to replace those later. I read previous posts from other threads, dealer will not replace those bushings even they install a new pump. End up the new pump is running very noisy.
 

·
Outstanding Contributor - Always Remembered, RIP
Zotye Auto 1.5T T600 2016
Joined
·
52,804 Posts
Thanks Eric, I will check the relay but the pump I think is good, my guess is, there might be some leak somewhere. Thank you so much.
If there were a leak in the system you would find other signs, ie low ride height or one suspension unit too low.
 

·
Registered
2002 S430 MERCEDES BENZ
Joined
·
10 Posts
Discussion Starter #8
That's the thing it does not drop, it is always on the right height but the pump is always running almost every stop I make. No leak on the upper part of it, I have to check the lower part maybe its there. Thank you. As soon as I work on it, I will post it what ever is the outcome.
 

·
Registered
Joined
·
25 Posts
did you have any luck finding out what the root cause was of the pump coming on all the time even when there wasn't any leaks? I have the same problem and am looking for direction.

thanks
 

·
Registered
2002 S430 AMG wannabe
Joined
·
115 Posts
If the car is not dropping, and the pump runs too much, there can only be two things wrong. Either one of the height sensors is sending the wrong signal, or the relay is going out.

Hella relays can be had from Autohaus in AZ for 8 bucks,...that's a cheap "test" (or one can swap the smog relay with Airmatic one and see what happens!).

As far as noisy pump,.....the only remedy is to get under, and check it all out. Mine has 76K on the clock now. I replaced the compressor a month ago, but I reused the rubber grommets, and springs.....the thing is as quiet as a church mouse. If the pump itself is "moaning and groaning", and the springs and grommets are ok,.....well you guessed it! It's time for the new pump.
 

·
Registered
Joined
·
25 Posts
interesting thing with my car is that I just changed the pump, valve block, height sensor links, Hella relay... all of it, but the pump still intermittently comes on as I drive - the car doesn't sink or anything, just comes on. I'm thinking it could be a leak in the air chamber? So as I drive, the pump is compensating for the air chamber leak? That's the only thing I can think of.
 

·
Forum Administrator , RC Colas® & Moon Pies®
1981 380SL 151K: 2005 S500 116K
Joined
·
39,203 Posts
I am reviving an old thread because I can't find the more recent one that I recalled reading before preparing to tackle the issue below. Some of the old discussion above is relevant to my own situation. Following my initial troubles with my airmatic suspension, including replacement of the shocks, valve block and other assorted relay bits and such, the car was maintaining height without any issues. It sat for over a week at the dealership during the recent window/quarter glass replacement and did not sink at all so I feel confident that there are no leaks, currently.

After the repairs to the airmatic system, however, I was frequently able to hear the pump when it came on. It wasn't horribly loud so I got used to it, putting it down to the car's age but I was sometimes aware when it was running, most often when decelerating into the bend of an interstate off ramp.

A couple of weeks ago, something changed.

The pump got louder and vibrated more noticeably and I heard it running in other situations as well. It got to the point that even my 'oblivious to any noise that a car makes' wife heard it and commented on it. It was time to investigate.

Taking all the usual safety precautions, I raised the front right corner, removed the wheel, front splash shield and the forward fender liner to gain access to the pump and valve block. Off the bat, I noticed that the right front mount was missing the nut/inner spring/spacer assembly and indeed, the threaded part of the stud itself was gone, no doubt wrung off by a previous tech since the nuts are apparently notorious for becoming rusted, seizing and then snapping off the spindly stud unless well lubricated in advance.



That same tech took a short cut and used a heavy duty electrical zip tie to suspend that corner of the pump from another part of the car's wiring harness tubing to keep the unit relatively in place and functional. To be fair, the people who did my airmatic repairs DID mention an issue with the mount but it seemed minor in comparison to everything else at the time and they didn't show it to me so I figured I'd deal with it later. It's later.

With the car still up on the jack stand, I drove the 210 to the pick and pull and found a 220 with the pump already gone but the bracket was still sitting there in plain view, mounted to the frame. The springs, nuts and washers were not there but I found one of the spacers in the dirt below the car that the other guy must have dropped and left behind so that was a bonus. Ten bucks and I was on my way home.

I pulled the old bracket (leaving the pump hanging from the suddenly convenient zip tie) and took the spring, spacer and nut to the local big box building supply store. I had discovered that I was still short one spacer since the rear one was missing as well although the spring and the nut and washers were still there. I bought enough parts to cobble together a similar assembly and after installing the new bracket, I remounted the pump using my Rube Goldberg parts. I don't know if the dealership had the necessary parts but I was in a time crunch so I just ran with it.

I buttoned up the underneath bits, mounted the wheel, dropped the car and took it for a drive. No more pump noise. There are times that I THINK that I can faintly hear it but truthfully, I had previously noticed that tire noise on certain pavement fooled me into thinking the pump had been running when it really wasn't.

After the next ride with the wife, I asked if she had heard it making the noise she had heard before and she didn't. The marital reward that she gave me following my mechanical wizardry was such that I...oh who am I kidding?

Regardless, the pump runs more often than you think but when it's all hanging how it's supposed to, you don't know it.
 

·
Forum Administrator , RC Colas® & Moon Pies®
1981 380SL 151K: 2005 S500 116K
Joined
·
39,203 Posts
Aaaand, looking at the pic above, I now realize that I installed the bottom tray upside down. :(



I'm blaming that other guy because I put it back the way that I found it.
 

·
Outstanding Contributor - Always Remembered, RIP
Zotye Auto 1.5T T600 2016
Joined
·
52,804 Posts
Aaaand, looking at the pic above, I now realize that I installed the bottom tray upside down. :(



I'm blaming that other guy because I put it back the way that I found it.
Chuckle snigger fart, been there done that:wink
 

·
Registered
2003 S500
Joined
·
2,476 Posts
A leaking air line or fitting anywhere on the system will cause the pump to run excessively. You can use a soapy water solution on the fittings to check for leaks.

A leaking air release valve in the valve block can also cause the problem.
 

·
Registered
Joined
·
41 Posts
"If the car is not dropping, and the pump runs too much, there can only be two things wrong. Either one of the height sensors is sending the wrong signal, or the relay is going out..."

Same problem I have on my 2012 S63 AMG, now with 100,000 miles on it. The pump became audible a while back and then I was able to tell that when starting to drive, the pump comes on for about one second, stops for about a second and then comes on again. Above 15 mph you can't tell anymore if the pump is running or not. I have been measuring the car heights above each wheel and they are all the same, look normal to me, with no more than 1/2 inch difference between the fender cut-outs.

I suspected a small leak somewhere, but should that not lead to the car settling down over night and then be lower in the mornings? Also, when parked over night, does the pump keep working to maintain the car's hight?
 

·
W220 Moderator
Joined
·
6,032 Posts
Hi,

You would probably get better answers to your question in W221 Forum, this forum is for W220 Cars :wink

Cheers Dave
 

·
W221 & Audio Moderator
2013 S550
Joined
·
10,912 Posts
The Airmatic systems on the W220 and W221 are similar; I would suspect a pump that may be starting to fail, OR a relay problem. Replacing the relay is cheap, but beyond that I would have diagnostics performed before throwing expensive parts at the problem.
 

·
Outstanding Contributor
2002 S430
Joined
·
1,923 Posts
Skylaw is correct about the systems being similar, in fact the Airmatic on most are similar and work in the same manner as each other. This makes working on the Airmatic of different models also similar. The compressor can be running excessive with the car staying at the correct height.

I find the best way to test the systems is to park the car with the drivers window open and connect Xentry/DAS through the window. First thing is run a quick test for faults on all systems, you never know what's in there. After this select the Airmatic control and set the car to the calibrated level automatically. From here run the pneumatic tests for leak detection. Final thing to do is level the car again and disconnect, measure the gap between the wheel centre and the wheel arches (write them down). Leave the car overnight and remeasure the next day at least 8 hours (12 hours is better). At this point reconnect and test the compressors ability to fill the reservoir.
This will give you a good indication of the condition of the Airmatic system as a whole.
 

·
Registered
2007 Mercedes-Benz S550 4Matic
Joined
·
13 Posts
Where is the relay located on the W221? I can't seem to find it anywhere in these threads. Is it in the same location as the W220? In the fuse box under the hood on the passenger side hear the firewall? Please kindly advise.
 
1 - 20 of 25 Posts
Top