Fuel lines on a w126 - PeachParts Mercedes-Benz Forum

Monomer · #1 08-25-2006, 06:34 PM

I'm a bit confused.

theirs a total of three lines running from the back. One of which I can identify as the send - it go's straight to the fuel distributer. Another line also hook into the distributer, but get sidetracked into what looks like an AC line.

Is this MB's way of cooling fuel?

Here's what I'm trying to do: I broke all three lines (in various place) that run right by the driver side wheelwell. It seems as if the rubber bushings hold in water, because every line that touched one is rusted - and most rusted through. So right now I'm "patching" everything. I noticed these lines run right nextto the exaust manifold, which is a shame because I cant be cheap and splice a rubber line in (which I did before noticing it's placement) I'm going to insulate it with fiberglass, no worries.

PS the bushing have to be a design flaw. I suggest spraying them with a rust-inhibiting paint (POR15) and then covering with spray body undercoating. this is NOT fun.

dpetryk · #2 08-26-2006, 08:55 AM

Short answer - Yes. That thing you refer to is used to cool the fuel returning to the tank. They do this because the fuel tank contents would be gradually be heated up since it circulates through the hot fuel distributor then back to the tank.

david s poole · #3 08-26-2006, 11:55 AM

one line is supply,another is return and the third is fumes from the tank to the charcoal cannister and yes the fuel cooler does exactly that.25 yrs ago i used that idea for an intercooler on a turbo 280zx-worked like a charm.

Monomer · #4 08-26-2006, 11:57 AM

Quote:

Originally Posted by dpetryk

Short answer - Yes. That thing you refer to is used to cool the fuel returning to the tank. They do this because the fuel tank contents would be gradually be heated up since it circulates through the hot fuel distributor then back to the tank.

ahhh, much like a vein pump heats oil up.

What kinda of pressure are we talking about here - The hose I bought is rated at 50PSI.

dpetryk · #5 08-27-2006, 08:23 AM

90 psi on the supply side almost nothing on the return side.

Monomer · #6 08-27-2006, 02:06 PM

Quote:

Originally Posted by dpetryk

90 psi on the supply side almost nothing on the return side.

The hose is holding up on all sides, I'm just wondering now if I have everything plumbed to the right place - she wont start right now.

Is there something I'm missing? A procedure to "bleed" the fuel lines of any air?

The Hoses are inplace of rusted through lines. What I did was flare the end of the pipe and connect the hose with the proper clamps. 90 PSI sounds about right, As I've been troubleshooting some small leeks. Does anyone by chance have a schematic of the fuel lines? (More specifically, the ones that run right into the fuel distributer)

Monomer · #7 08-29-2006, 11:05 PM

Can someone please Identify the two lines in the second pic.

I'm afraid I have lines crossed, And need to double check. I cant trace them that far back because the diff is in the way.