sredwine

Our 2005 E320 wagon (no Airmatic, just air springs in rear) is intermittently losing pressure, the right side usually drops more . It can go a day or two without a problem, then drops overnight. This morning it was up at normal height all night. Then an hour later with no one touching the car, it was down. I started the car, it pumped up, shut off car-right side drops, I hear a hiss. Leaking bag, right? I started the car again, it pumped up, shut off engine, no hiss and it stays up. Can this be a leaking valve or hose? I can't see how a bag with a hole would act this flaky. I would like someone to explain the system and its valves, lines, etc. I have seen some pdfs but they don't show a schematic of the air path, valves (electric and not), etc. I don't want to buy new bags from Arnott only to find there's a cracked hose or intermittent valve, etc. Also, I note that Arnott's rear air springs for the wagon reuse the old valve-that gives me pause.

Plutoe

I know you won't like my response, however if you only do one thing, do not take the car to a local grease monkey------because you do not want to take the car to a dealer who has the special tools to repair the high pressure lines if there is a leak and the diagnostic equipment to test the rear axel level control valve and sensor and or to drain the system of air prior to repairing-------therefore because you do not really know what is faulty, you have very limited options---although very unsophisticated you can test for leaks in the high pressure line.

The recommendation is to test two locations for leaks-----one under the rear seat there is a rear distribution valve(three connections) and under the car there is the connection at each air spring.

You can purchase leak detection spray to do the job--DO NOT spray with ANYTHING else except soapy water or leak spray, because if you do you are in the Sh's

PS:----If after doing all this-----who is going to repair the system??

sredwine

I installed Arnott replacement springs and reused my old valves-so far so good. I noticed the leaking spring (right side) was original (Mfg date 2004), while the left side was dated 2008 and looked a little different. Replaced both anyway. It took me a while to figure out how to depressurize the springs (both were holding air just fine when I began work)- I applied five volts to the valve solenoids with the main air line under the car at the union that feeds both rears disconnected. The system is pretty simple-compressor applies pressure to the air lines to both wheels, computer opens valves to add or reduce pressure in each independently. A leaking bag will not deflate the other side as long as valves are sealing when car is off. I had a couple of problems with the new springs-the cap on top had the mounting holes drilled a little too far apart-just opened them up a little with a drill bit, solved that. The machined billet aluminum bases of the springs would not drop into the suspension arm-ended up filing, sanding them, even then it took a lot of muscle. Tricked the suspension into thinking it was sagging with a jack and jack stand under each wheel-bags inflated, car driving great!

imaslev

sredwine

I used a 5 volt power supply I had lying around; a supply from an old modem or the like would work. For all I know battery 12V MIGHT work. But if a computer's directly controlling the valves, 5V seems as high as you should go. You don't want to fry the valves-you can't get them except with a new set of MB bags! Arnott's bags do not include them.

imaslev

my new Arnott comes with a solenid so Im trying to diflate one of the springs
if i app a 5volt strait to the bag it going to open the solenoid?

sredwine

Yes, the wiring to the top of the air spring disconnects near it-there is a two pin connector. I used small test leads. Meter probes would work fine, just don't short them together or you could blow your power supply.