Me three. If it was a hard line you would see the rust being wet in the area of the leak. Especially if were talking about a diesel engine. It'll lube the leaky area of the line and be very obvious. Rubber hoses, being what they are, are likely culprits when it comes to a leak.

I don't know how Mercedes holds their fuel tanks up but if they use straps like the rest of the world there's a fair chance you have a leak in the tank just up under the straps. Road dirt and salt hang up in there and make a really nice spot for rust holes to start.

Heres a tip, fill it up most of the way with fuel. that will add more pressure to the leaky area and will help you diagnose your leak. Unfortunatly if it's a leaky tank, now you have to siphon a full tank of fuel out of her.

The car I just picked up has two fuel leaks. One is the hard return line right about in the middle. The other is the rubber return hose that connects one injector to the next. Someone replaced the original with something from the hardware store. Which in of itself would have been fine but he didn't use any clamps!

So for me, both leaks should be easy fixs. Chop out the bad part of the hard line, replace it with rubber fuel line hose and a couple of hose clamps. Then find some very small hose clamps and put them on the leaky return hose on the injectors. I think I'm looking at a whooping $6 bucks or so.

Could anybody loan me $6 bucks? LOL

Wayne