token

Hi Guys,

So my airmatic compressor finally gave out. Last Friday when I parked the car I heard the compressor running. I just thought, hmm, that's strange, but now I think I understand what happened...

On Monday when I drove the car to work I got a ride height malfunction.

From what I've read, the relay seizes which causes the pump to stay on, which then burns out the pump and blows the fuse. Does this sound right?

I replaced the relay and fuse, but the pump didn't run and the new fuse blew immediately. I have a new pump on order, and I'll swap it out when I get it and then leak test the system to make sure there wasn't some other problem causing the pump to run too long. But it's a 2007, so from what I've read, it's about time for the pump to die of "natural causes."

But the real question I have is why isn't my car sitting on the floor? The ride height seems OK; I have about 1 1/2 to 2 inches between the tops of my tires and the wheel wells. The ride seems a bit stiffer, but not so bad. I had expected if the pump failed that the car would drop to the ground and I would get the dreaded car-too-low-stop-driving message?

Any idea why it's not sitting on the floor?

Nickthegreek

The reason why is because the air pump does not just directly pump air into the air bags. That is done with reserve air tanks that are under high pressure along with air regulator valves. So the system is constantly removing and adding air from that tank. Once the tank runs below a certain level then the pump brings air into the tank. So right now your reserve tank is pressurized but eventually it will slowly leak out. As you take a corner/go over bumps etc it lets some air out and refills so as you go over bumps and take corners it will slowly lower. It prolly wont slam as long as the valves still work but I wouldn't drive it for now until you get a pump. it might make it too low to get a jack under. I made a link on installing the airmatic pump. Its real easy just search it on the forum. I got pics and everything. any questions lemme know

token

Hi Nickthegreek! Thank you for the info! Yes, I've seen your DIY; thank you for posting it. I've got a pump on order and I'll be installing it per your DIY as soon as I get it.

For the last couple of days the car has stayed at the same height, which surprised me. It's good to know that it will probably sink over time. I'll have to be careful.

Nickthegreek

No problem. Also a big word of advice, if you live in the northeast or where salt is used on the roads get a new bracket. It will be rusted frozen on there and the threads will break right off when you try to loosen it. save yourself some trouble. Also there will be a check valve you have to unmount from the frame to make room to get at the bracket. Anti seize all bolts and nuts when you install everything back together

token

I'm in SoCal, so hopefully I won't have that problem. But if I do, do you know the part number for the bracket off hand?

EDIT: Nevermind, I got it: A 221 320 02 43. Also, if anyone is looking, the part number for the Tyco relay was 002 542 23 19, but it was replaced by Mercedes with a Hella relay, 002 542 76 19.

token

Just an update... I received the pump yesterday and swapped it out last night. Very easy job that took me a little over an hour start to finish, just because it was my first time and I was being slow and methodical. Luckily, being in Southern California the nuts holding the pump on were very easily removed with no corrosion present. I replaced the relay and fuse, started the car, pressed the rise button, and voila! Working airmatic system!

Jason B

How much was the pump?

token

I got it here for $340.20:



By the way, I can confirm that the brand of the old pump was also AMK, the same as the link, even though the new pump didn't have the Mercedes logo on it.

Jason B

Very cool! What's the dealer charge for that? Probably $800?

token

I'm not sure; I didn't check. I saw other reports on here that people were spending $900 to $1000 for the job at the dealer, and I figured I would save myself some cash! lol

Quadcammer

You can get an OEM in an MB box pump for $382 at oediscountparts.com with free shipping.

Dealer msrp is $510. They'll hit you for a few hours to do the swap, which is easy.

token

Just curious, but is there any reason to buy the pump with the Mercedes logo versus without, when it's made by the same manufacturer? Does Mercedes actually do any additional testing to the components that would justify the higher price? This is an honest question.

Quadcammer

I doubt it greatly. In most cases, bosch, denso, pierburg, xyz supplier takes one part with an mb stamp and puts it in the mb box. They take the identical part without the mb stamp and put it in their own box. The difference in price can be massive but its the same part.

In some cases, that are typically well identified, oem parts have proven not to be as robust as MB stuff.

Donnymac

Great explanation and advice in this thread. Thank you all.

Nickthegreek

Awesome to hear!!!

PS- I hate you guys in the west where your cars don't rust like here in the northeast :P

For such a simple repair the dealer will take you for a ride in pricing. It's about 1000 to have it done at the dealer here. I went with the MB pump for 410 at my dealer and 85 for the bracket so I paid 500 still half what they would've charged with labor

Jason B

I leave it in "sport" suspension mode, which keeps the car lower. One would also think that the compressor would run less in this "lower" sport mode, but that compressor just runs a lot.

Now, I know people said this isn't right, but it must be. After I park the car and it's been sitting for a while - if I open a door, I will hear an air release sound. It's can't be coincidence. Not every time, but 80% of the time. If car is sitting in garage and I open a door to get something, psssssst air release. Something must be tied into the door, or when the door handle is pulled to randomly release air.

Nickthegreek

Same. My theory is that is priming the suspension because it is anticipating a load ( you sitting in it)

newguy2008

Did you get the pump like this one: Mercedes-Benz Genuine Factory Part

Fits 2007 Mercedes-Benz ML63 AMG Base

Part Number: 1643200904
COMPRESSOR ML63 AMG
Item # on image
MSRP: $510.00
Online Price: $382.50

I ask only because the description on their web site says: " REAR SUSPENSION - RIDE CONTROL - COMPRESSOR", so I'm a little confused.

"You can get an OEM in an MB box pump for $382 at oediscountparts.com with free shipping."

Nickthegreek

Look for part number A 221 320 17 04. Oh wait after reading your description do you drive an S or an ML? If its an ML you might be better off asking in the ML forum

1bad540

Mine does this too, only if you have the key near by tho. I was actually gona ask you if yours did the same.

s550148

Just replaced mine 800

marthyh

Same here,my theory however is,that when the (heavy) door is opened, car slightly tilts, car wants to level itself within nominal specs by equalizing the height on the corner (the airsprings) concerned, releasing excess pressure on the appropriate valve..but thats my guess..