My F-350 has developed a pretty steady fuel leak. It is dripping out of the connection on the larger of the 2 lines right under the front of the head on the drivers side. Does this mean a new line? Is it one piece back to the fuel pump? Or is there a seal or some way to fix it?

 

If it's leaking out the fitting at the fuel bowl, there will be a sleeve or o-ring in there. If it's leaking from the middle of the hard line, you can just cut it in two with some tubing cutters and use a short piece of fuel injection rated rubber hose and some hose clamps as a splice.

 

It seems to be dripping out right at the connection where the line changes to steel.

 

Check the hard line that crosses over the valley and connects to the fuel rail on the front of the drivers head. They can rub on the IPR nut and wear a hole through the fuel line.

If the hard line is OK, it may just be the compression sleeve that has deteriorated enough to begin leaking.

 

While it was leaking I put my hand around the line above the leak and it was dry, so I have to assume it is the connection from the hard line to the flex line.

 

Are you talking at the fuel bowl? If so, the top or bottom line?

 

This is under the head below the oil cooler in the front. I thought it might be the cooler but that seems to be okay.

 

I am thinking you are now talking about where the hardlines transition to the flex lines as the lines cross over to the frame.

If the truck has spent some time in the "salt belt", road salts will collect in the quick connect fitting at the transition and corrode the hard line away. It may or may not be possible to separate these connections with a fuel line tool but the two lines that come down the drivers side of the block is a one-piece unit. This part is available from the dealer but you may also need new flex lines to go with it if the salts have corroded the flex line ends badly.

Some with simply replace the entire line from the pump to the fuel bowl with 30R9 fuel injection hose that has been protected with plastic wire loom.

 

The quick connect fitting is what looks bad. But I have not pulled it apart yet. I have to drive one more day. It is only about 5 miles to where I am working. Then I can have a look. If I use fuel injection hose, where can I get it and how do I make the connections?

 

The fuel line from the pump is 3/8". The return line to the tank is 5/16". This would be the hose ID you would need, depending on which line is leaking.

If you disconnect the line from the pump outlet, the quick connect barb on the outlet will allow you to slip a 3/8" fuel injection hose (30R9) over it and connect with hose clamps.
Then you would have to pull the lower fitting on the driver's side out of the fuel bowl and replace it with a 1/4" MNPT x 3/8" hose barb fitting. The hose can be fastened to this hose barb with hose clamps.

The return line may be a little more difficult as I do not know of a hose fitting that will fit the FPR threads. Maybe someone else here has found one and can report what they used, but in the worst case, you can cut the 5/16 line a few inches back from the brass nut, slip some 5/16" fuel injection line (30R7 would work fine on the return line due to very low pressure found in this line) over the tube and double clamp it. The same connection can be make on the chassis side of the return line.

Make sure to protect all of the hose from chaffing on the frame or radiator bracket with some plastic wire loom and fasten in place with plenty of wire ties.

 

Look up hoses and fittings in your area yellow pages and look for a place that sells it. Call a few places and ask them if they carry 30R9 fuel injection line. If they say no, then ask them if they know a hose and fitting business in the area that sells it.
Advance Auto parts sells it in 18 inch lengths in the help section. I do not know if they have it by the foot behind the counter. Pick up the yellow pages and your phone and look at the above general directions. If you told me exactly where in NJ you live then I can do a google search for "hoses and fittings $$$$$$$, NJ" and it will come up. Like this google search at your state level
Google

Dwayne

 

I stopped at Advance on the way home. They have the right fuel line in bulk. $4.95 a foot. I'm going to replace the whole line. I got the right fitting for the 3/8 line. I will pull it apart in the morning and go get what I need. Do the threads on the fitting need to be sealed with anything?

 

Yes, it will require a thread sealant but do not use teflon tape ... bad for injectors if a shred makes its way to one.

Use a liquid or paste pipe dope and don't over torque the fitting as it can easily crack the fuel bowl.

 

As in regular plumbing pipe dope?

 

Well the job is done and the truck is running. I couldn't find a wire loom big enough to cover the fuel line so I used a piece of garden hose over it.

It doesn't seem to leak anywhere, but it was getting dark so I will check it over tomorrow.

Thanks for all the help.