CQHall

Thankfully, all of my multi-contour seat bladders are intact, hold air, and work as expected...most of the time.

Maybe about once a week my driver's seat will inflate a random bladder (usually the side bolsters or shoulder bolsters) and hold them stiff. When I go into the menu, the setting is as I left it (usually 0 or 1), but it feels like it's jacked up to 10. I have to manipulate the settings up to 10 and back down to 0 to get them to deflate.

Any idea what's going on?

Senecat

Air leak.

CQHall

I'm not doubting your diagnosis which could very well be the case with a car so old (2008), but help me understand how an air leak would cause the bladders to inflate? And when doing so, inflate much harder than the original setting (0 or 1)?

My guess (and it's just a guess) would be that the module that regulates the pressure for the bladders is somehow borked. But, being that these cars are so old, I figured someone may have experienced and solved this already.

vettebk

I think if it was the module it would post a code. Did you check for any codes? If there are no codes, then it is more than likely you have a leak as Senecat indicated. If the bladder had a leak, the pump would try to reinflate which is what you are feeling. My 2007 has an intermittent leak in the drivers seat but not the other seats and gives the same feeling (it blows up and then deflates again). There are some posts you can research on this site with photos of re-tubing the bladders. It is a pain.

CQHall

I'll check for codes.

BTW, it never deflates again unless I go into the user interface and slide the slider to max then back down to 0.

CQHall

You two are right. I just ran a scan with my Autel and got these two stored codes:

• 9200: The module carrier for the backrest is faulty.
• 9251: Pressure loss is detected owing to leakage.

JohnLane

My ‘06 E55 did as described.... Too often it would decide I needed a FOOTBALL for lumbar support, in a side bolster or shoulders.

Module solved it until the car got fixed with a 221 S65.

CQHall

When you say "Module", do you mean that you replaced a module? If so, which one?

Maybe the module is malfunctioning and reporting a leak that isn't there...and that's why it's over-inflating?

JohnLane

If failing memory serves the module comes conveniently packaged with all the air bladders that go in the seat back. Get to peel the seat to do it. Not as awful as it sounds. Hog rings FTL. Having the seat out is your opportunity to replace the bushings the seat pivots on as they are going to be worn out. I used a Volvo 240 manual transmission shifter pivot bushing to do that. Fit well and readily available.

vettebk

This post may help you with the module. The tubing is another set of posts.

https://mbworld.org/forums/s-class-w...placement.html

vettebk

And here are the posts with the pics to help you. Also the air tubing stuff. You should be good to go.

https://mbworld.org/forums/s-class-w...g-fixed-b.html

CQHall

Yeah, I did the complete job for both seats on my E55 where almost all of the bladders were torn. It was a bear.

Documented here: https://mbworld.org/forums/w211-amg/...-my-seats.html

Senecat

You're already a pro. You got this.

Senecat

One of these days I'll be tearing apart both of my front seats and replacing all tubing. I repaired some driver seat tubing shortly after I bought the car enough to where the compressor wasn't constantly running but the seats still only function about 40% and I know there are still leaks, and if the driver seat needed repair, the passenger will as well. I'll get them back to 100% soon and post a thread. All tubing will be clear vinyl tubing from the local ACE Hardware. After restoring the pneumatic system, my seats will be A- condition, there's only one small scratch on the passenger side but other than that, they are pristine with extremely well condition leather. I really love the 221 seats.

nath_h

Has anyone replaced the cushion pad on the bottom or back? Mine still feels okay, but that foam material seems to deteriorate/fall apart over time. Curious how the job went, if anyone has tackled this project.

BOTUS

festo (they do industry wide pneumatics stuff for machinery) make pipe that is very similar to the OEM, but tend to use a different diameter... their stuff is rated at >8 bar

Senecat

It's such a low pressure system that the clear vinyl tubing will not only be sufficient, but look bad *** too.

Thanks nath_h for mentioning replaceable seat pads, I may incorporate those into my resto project. Being ventilated though, I'll have to figure that one out.

Senecat

8 bar is more pressure than the engine lubrication system, I think we can get away with less! Lol

slickman

I'm dropping my 2012 off for this same issue but, fortunately for me it's under warranty.

BOTUS

the seat squab on early cars (I guess pre 2008 facelift) had fans that fall off if fitted, and the foam and seat cover came bonded together - you are meant to buy the assembly for $1200+ just to get the lower heated element to work

post update, the cover and the foam are two Items - I guess Merc bit themselves when all the fans disintegrated and or rubbed on the foam of early cars (due to appalling build) and USA got new ones for free - the rest of the world just got screwed - its why ebay USA have so many to buy second-hand

inside of the cheap nasty cloth bit that is the rear impossible to fathom clip in section of the seat squab cover - is a label with the part number build date and trim spec - and you can change the seat squab with out disconnecting any wires or unbolting the seat - but its not much fun...

check the big seat fix post - a few clues there - the nastier than a toyota aygo quality plastic trash trim around the seat base, is basically not held on by anything, but its hard work trying to fathom how it comes apart

see post #42 for what the squab looks like

https://mbworld.org/forums/s-class-w...g-fixed-b.html