Fuel leak from behind fuel filter - need service manual diagram
 

Went to start my truck this morning and it sounded like it had lost its prime - not even a stumble. Over the past few days I've been smelling some diesel fuel when I shut the truck off, and have been noticing more stumbling than usual during the first start of the day.

Long story short after rubbing my thumb raw on the primer button I was able to get enough built up to get it started and find the leak. The leak is from a fuel line (I believe its rubber) between the fuel filter and the engine block - it "pulses" fuel out of the crack when the engine is running.

My filter wrench is at work along with all my other tools (why do vehicles never break down when I'm at the shop?? [laugh]) so until my dad brings his filter wrench by I can't really tell where this line is going.

Does anyone have a service manual page that shows where this line is running just so I can have an idea of what I'm dealing with, and if I even want to attempt messing with it at home or have it towed into work.

Thanks,

Dennis

Most likely the return fuel line 5/16" dia. I use EFI hose and clamps to replace. Runs behind fuel filter and to top left side of trans where a bracket is located then into a steel line down to a braided hose with a quick disconnect. I have changed many of these hoses over the years and not very easy even on a lift. But at lease your truck is not 4X4 that makes it a little easier.

Here's link to show fuel line location

https://www.dieseltruckresource.com/...tted+fuel+hose

That replacement hard line is next to impossible to thread in without removing the injection pump. As mentioned above, I threaded some new rubber line in after cutting out the cracked section. Easier if you pull the fuel filter housing also.

As has been said, it is the return line. I haven't lost the rubber part first though, mine have always dies at the flex SS line down by the drivers feet under the truck.

Now, whenever I have to deal with one, I just replace both 5/16" return and the 3/8" feed lines from where they connect at the engine, all the way back to the drivers side frame rail, that way you get rid of the flex hose, quick connects, etc. The 5/16" return line is challenging to get at, but I have managed every time without removing the filter head, i just take off the FF. YMMV.

Oh yea, and at least this last time, I couldn't get it to re-prime with just the button, I had to use air in the tank to push the fuel up to the LP to get it started. Might just have been my LP priming circuit is getting weal though, I had never had to do that before.

Thanks, tomorrow I'll go get some 5/16th hose and a couple clamps and see if I can get it repaired. I take it that the rubber line just slips over the hard lines?

Well, I managed to get the line off at the front but have had zero luck finding out where I can disconnect it and just replace a section of it. I'm beginning to think that just replacing the whole line with a good rubber hose all the way back to the tank would be the easiest way to do this so that I can be back up and running by tomorrow. Can anyone show me where on the tank this return line connects? Do I just use a hose clamp on the tank end as well or do I need to get some other kind of connections for the rubber hose?

Thanks for any advice,

Dennis

Dennis, you can pop it off at the sender quick disconnect and run it all the way back, but unless your lines are rotted running along the drivers side frame, I usually just go back a foot or so from the front quick disconnects, pull the lines away from the frame enough to use a Rigid tubing cutter, and go from there up to the engine.

Hose clamps will do just fine either way you go.

You're a wise man.
That's the only way I do it any more. Not only is it easier but is insurance against the rest of the stock system failing.
The metal lines develop leaks too.
Replace both the supply and return lines with hose all the way to the tank while you're at it.

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