dmingo777

I have both seats removed from my SL trying to locate the air leak preventing both passenger and driver lumbar operation. I've opened the sheath that contains the hose and neither side seems to have a broken hose. When I blow into the driver's side tube there is no resistance. I have reset the 20amp fuse.

Shouldn't I hear air noise when the key is in position 2 and the control is activated? Where is the hose junction between the two seats? Don't know where to look next. Any help?

thanks

Lee Wireless

see attached. Let us know what you find.

dmingo777

Great, a diagram. That helps a lot. I'll "dig" into that tomorrow and let you know.

Thanks Lee Wireless

Essell55mb

It's all covered in the attachment, but I would just add I found my leak in the hose from the floor pan to the seat since this is bent and flexed from seat movement.
I bought a mityvac vac/ pressure tester which helped isolate the problem.
You should feel resistance if you blow into the tubes, if not that suggests a gross leak.

Also as mentioned in the attachment, if a leak is detected the vacuum port for the seats will be disabled until re enabled by star. Hence you won't hear any hissing if you have a leak.

dmingo777

More info. Thanks Essell55mb. What did the Mityvac set you back?

Heatwave

Dmingo777: Amazon Prime has Mityvac hand pump kits for $34.22. Harbor Freight has one (not a Mityvac, but a Chinese knock-off) for $24.00. Good addition for your tool chest.

I got a Mityvac many years ago ... used often for bleeding motorcycle brake lines. I see now how to use it to troubleshoot my R230's pneumatic lines.

I thank all who posted above for sharing their knowledge and information. I have just enough information now to make a real mess of things.

Essell55mb

No worries, I went for the metal bodied mityvac that does pressure and vacuum , was about £85 on eBay. Really useful tool to have in your collection.

Also worth noting I repaired the rigid (cracked) air pipe by making a clean break and using silicon vacuum hose to sleeve over and reconnect the two ends.

Essell55mb

To find the leak I ended up isolating sections of hose by cutting them and sealing the ends temporarily with the same hose and the conical stops you get with mityvac kit

carguyshu

the lumbar air bladders are also famous for splitting at the seams inside the seat. You can either take them out and take a heat gone to remake the seam or you will have to wait and have some made by mercedes in germany to get new.

Lee Wireless

Any update on the leak repair?