95viper

Put this over in the CLS forum but applicable here too so will ask you guys.

Going to start searching but woke up to a front passenger shock down. I started the car and it cycled on and off every few seconds raising the car up a little but would not go all the way. I pressed the raise button and it didn't help. Dash just says raising vehicle. No warnings about being low.


I will search for troubleshooting steps.
07 cls550 29k miles

Ok weird. A gremlin is in there. I do some basic tests. I start car and try different settings. I press the raise vehicle button. I hear compressor and right front trying to rise. It gets an inch or so and I hear an air release. Then dumps back down to stops.

Here is where it gets weird. I stop car and check all around. Driver front and passenger rear normal but driver rear up max. I assume maybe because the front passenger is so low?

Then I lock the car with key and compressor dumps air all around. All four are low now and passenger front is lower than the others. It is on bump stop. I start car again and nothing appears to rise now. I hear compressor try again on front passenger but nothing.

Thoughts?

kajtek1

Why do you start new topic, when we have 100 identical already?
If you have easy access to SD, you can start reading the pressure raise in the system.
Without SD the easiest way is starting with compressor service/rebuild and checking for visible air leaks.
Again, lot of topics covering the issue.

95viper

Thanks kantek1, After searching airmatic and reading hundreds of posts I certainly found basic troubleshooting steps, which I started, and I found many intermittent issues but I didn't read a condition like mine where one wheel started the issue, then another raised really high, then all went low with the one even lower.

I guess the raising really high is what threw me off. Sure wish there was someone in Phoenix who makes house calls with Star.

kajtek1

Try to understand the system. It is pretty complicated, with several items interlocking each other and no indication to driver what is going on.
If you found my topic about compressor service, I installed pressure gauge that will answer about 50% of questions that might come with system malfunction.
Not knowing how dirty is air filter, how much water you accumulated in the system, if the system hold the pressure or is having leak, what is condition of your level sensors.
We can talk for days about possibilities, but somebody needs to put his hands on the troubleshooting.

95viper

Lots of testing today. Put front suspension on jackstands and removed fender liners. Started car and all wheels raised except passenger front. Lots of hissing around shock but soap in spray bottle test couldn't find anything. Compressor seems to be trying to fill it up and then gives up.

Soap test on compressor lines and valve block did not find any leaks. Car has 29k miles and everything "looks" new.

Maybe a dumb question here but wouldn't it be a cool test to disconnect the line at the top of the shock and put a pressure gauge right there? then I could validate the pressure getting to that specific shock

.....or is it possible to hook a compressor to the shock with line disconnected? I could T into the line at the compressor as I saw in my searches but curious if this would work right at the top of the suspected bad shock?

kajtek1

Pressure in the main line is going to be the same no matter where, unless you have major air draw (leak)
I Tee the gauge close to compressor, but later discover the tubing going under rear seat, what is more convenient location.
Going back to hissing, you should feel air flow with your skin. Not the hand, where skin is hard, but with forearm. Soapy water works on bubbling but not on big flow.
If that does't work - buy a pack of CUBAN cigars and start blowing smoke.

Plutoe

You are being run around the may pole and or in circles----simply find someone with the proper diagnostic equipment and he she or it will tell you in ten minutes the location of the fault-----then you can apply your excellent wrench techniques to replace the faulty part!!

95viper

Haha, love the cigar comment.
Plutoe, I actually think that I am 99% there. My last test is to try a compressor connection right on top of the shock. This is because it tries to fill it up for about 30 seconds right when I start it, and I think I feel air leaking around the shock, but the engine running with fender liners off moves a lot of air around that area too.

Having a compressor connected at the shock eliminates everything else. This assumes that I can figure out what fittings to use ☺.

I would gladly have towed it to a dealer for a real Star diagnosis but that would be $300 towing round trip and Star and I will save that as last resort.

kajtek1

Plutoe is known commercial scammer and forum clown in his free time, but he is right that SD would make the troubleshooting much easier.
Bad part that even after spending $300 for towing, $300 for troubleshooting - most likely you will get $3000 job estimate for replacing 2 front bags.
That is what Plutoe wants you to do.
Now- hooking up compressor to shock alone is not going to tell you anything.
You need to activate the valve on top of the bag to see if the bag leaks.
I recall seeing on the net options of opening shrader valve where air line is connected, or someone figured out wiring at the valve for electrical operation.
Still I think with you already hearing the hissing - visual inspection of the bag should be sufficient.

95viper

Dang kajitek1, I never even considered the shrader valve. Totally overlooked that on the previous posts. Thank you. Your information has been priceless.


I am back to more visual inspections tonight and trying to feel the air.


Thanks!!

cmriv

:h ammer:: smash:

95viper

Alright guys, 100% found the problem. Today the darn strut started whining loudly as it tried to inflate. I physically moved it around and it was changing pitch like a choking chicken. The bladder sounds like it exploded. I ordered from Arnett and used the forum discount. Thanks everyone for your help. I will search for install tips but it seems straightforward.

On a positive note I had time to replace both window regulators in my BMW and the kid across the street was helpless on a dodge crankcase sensor so I dragged some tools over there and replaced it. They certainly didn't make access to that thing very friendly.

kajtek1

Darn you. You found broken bag without $20,000 diagnostic computer
Some minds will never get the idea.
I am happy for you. Still if you plan to keep the car -think about adding pressure gauge.

Voland

A member who l believe is an MB tech but may no longer be active suggested most common issues concern worn or shorted wiring in the area of the valve block and pump...forward the wheel well. Pulled codes (3) that indicated issues with the Pressure Release Valve and Switch on the pump. Opened the skirt and sure enough, the tiny brown wire at the connector had worn and broke. Replaced the connector and the car immediately began adjusting level, filled the bags, ran like new. Saw several other worn wiring issues for the future. As the system at this location is suspended and moves a lot, worn fine wiring is suspect for many issues.
Pull the codes and isolate the problem(s). That's what they're there for.

95viper

Thanks Voland. Mine dropped overnight and never threw a code so nothing to pull for me.

95viper

Finished this weekend with an Arnott replacement. Used the 9volt battery trick to release the air from the strut. Getting it to compress sure was drama. I popped the upper a arm ball joint to get the suspension to drop just enough.

I know the w211 and w219 might have completely different clearances but did any of you disconnect the sway bar? I was ready to do that when it finally went in after hours of trial and error.

Rides perfect now. Thanks everyone!!

95viper

Just watched a video and think I found my problem. I had the driver and passenger jacked up for testing but left on stands under the control arms. I should have jacked up the driver side by the body (like I did on passenger side).

By leaving driver side on the control arm I was fighting against myself. Sway bar was being forced up over there while I was pushing down on suspension on passenger side trying to get the strut in.

Make sense?

kajtek1

I am visual guy and takes me long time to paint a picture from the words, but whatever works, it works and that what counts.
Happy motoring.