My 98 has a pretty bad fuel leak under the engine. It's a constant drip, drip, drip (while the truck is running).

I'm sure it's the supply line leaking somewhere but I haven't been able to pin-point it.

My mechanic said that it's a High pressure line (metal) that has the Quick Disconnect on it. He said the whole line needs replaced because it is one piece from the engine to the tank.

I thought I read it can be replaced with regular rubber fuel line. What's the deal here ??

Also, where does the supply line connect into coming from under the truck ??

 

Not sure why he said the entire line needs to be replaced. You have metal lines along the frame rail, then they become a section of braided line, then a short section of metal, then a short section of rubber hose which connects again to the metal lines that bolt to the fuel system components.

To me, that is to many connection points, so I cut the line at the frame where the braided sections begin, flaired it and installed rubber line the rest of the way up to the metal lines along the engine (the ones that connect to the prefilter and the pump).

This is the connection point before cutting and bellmouthing (flairing) the ends:



This is the fuel lines after everyting has been connected:



It eliminates all those conection points, potential for leaks in the hoses (metal, rubber, and braided) and makes life easier next time you have to replace the lines. The rubber tubing just gets routed in a safe location with a few zip ties. I used wire loom over the hoses to protect them at critical points.

It's just a shortened version of what Infidel reccomends. He suggests going wih rubber lines from the hard lines at the engine all the way back to the tank. KD

 

Do you have any pics of where the metal line goes from the firewall to the prefilter/heater ??

I "think" this is where mine is leaking from. ????

 

Are you sure it's not the return line from the injection pump? Had mine crack while on a trip last year.

 

Rloren has a good point. You need to check your hard and soft lines to make sure of what is leaking. The hard line can be stressed (forced while working on it) or just plain old work hardening from vibration can cause a crack.

However, if your hoses have not been replaced, then it is time. Here are a pic of the return line that may help (courtesy of Infidel):



Can't find a pic of the feed line, but it goes to the fuel preheater. You can slightly make it out in that pic, but it is hard to see. Find the preheater according to the above digram, then follow the hard line that goes along the engine block and then towards the tranny. Be careful as the hoses cross and you could follow the wrong one.

The way the feed goes is from the tank to the prefilter/fuel heater assembly, then a short rubber hose goes from the preheater to the lift pump, then from lift pump to the filter aseembly.

Hope this helps some, KD