Left drivers side over the half shaft there are 2 lines exiting the fuel tank. One may be the fuel tank vent valve as it is cylinder shaped white plastic. The other has a 90 degree rubber molded line exiting the tank and attaches to hard line. What does this line do? My 90 molded is damp and if I replace it will I have to empty the tank first? Should I try to source a 90 degree molded or will a rubber fuel line work. Than you>

I can't quite make out your description, but on my '88 190E there is a molded hose that attaches the tank to the manifold that connects to the fuel pumps, filter, and accumulator. This molded hose has an integral smaller hose that attaches to the fuel accumulator, so if the accumulator diaphragm cracks the leaking fuel will short back to the big hose preventing an external leak.

My fuel accumulator failed a few years ago, and I tested it by removing the small hose from the accumulator, placing it in a plastic bottle then turned on the ignition, which briefly energized the fuel pump, and it leaked fuel.

The symptoms were intermittent long cracking that became more frequent with time. I documented the problem in a a couple of threads I started including photos of a destructive analysis of the accumulator including photos of the cracks in the diaphram that cause it to leak

Duke

Thank you for reply. Tomorrow I will try to find a picture of what I am talking about.

Pretty sure the answer is simple if anyone could understand the question.

Here is photo from the internet, it is not exact as I don't think it is from W124 but it is very close regarding hoses.

http://www.peachparts.com/shopforum/attachments/tech-help/163552d1635099598-260e-w124-petrol-fuel-tank-mb-w124-fuel-tank-outlets.jpg

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Sorry, I still can't make out the issue. It could be that my 201 is a different design.

Duke

Thank you for replying. My fuel level is getting towards reserve so I think I will just pull hose off and see what happens.

On a Ford, that might be a tip over valve. Closes if the car is upside down. I don’t know if Mercedes used tip over valves. It might also be a check valve for the evaporative emissions system. There’s also the possibility I’ve no idea what I’m talking about

Michael

Pulled what I think is a return line hose and drained a couple of gallons petrol.
Installed new 5/16 or 8mm hose, Old hose had some small cracks in it and was wet but did not drip.