Fill neck mod?

Okay Im at a good spot to mod my fill necks. The back tank hasnt hardly taken fuel scince Ive owned the truck. From what ive read you basically gut the rollover valves, splice a new barb in them, and run a line up to the top of your fillneck. My question is what kind of fitting do you put in the fill neck, and what size line do you use? Ill do some more digging, but thought I'd ask to be safe.

Thanks

I used 1/2 inch fuel line on my setup. The rollover valve gets replaced with a 3/4 inch bushing and a 1/2 inch street ell fits that and the fill neck. The only other part you need is a 1/2 male pipe thread to 1/2 inch hose barb fitting. Be good to youself and remove the rear tank float pickup and replace the broken off suction. The rear tank will need to be dropped around 3/4 inch so all the hose and fittings fit and not hit the truck bed. My system still wont fill as fast as the regular fuel nozzles can push fuel... I don't know why either. I even cut off the roll on the steel fill necks where they couple to the rubber tank fill line. Really no differance. I thought that rolled metal lip was distrubing the fuel flow.... Another member used 5/8 hose and fittings. This mode does allow more fuel to be pumped into the tanks and faster than before... I just know the big rig fuel nozzles wont work for me.....

I used 5/8 fuel line on my mod and the tanks fill as fast as the reg pump will pump. Keep the breather line above the top of the tank or else you might get fuel in it and it won't drain back into the tank thus blocking any venting. Also when you put the fitting on the filler neck have it aimed up or at least not aimed down as this will also allow fuel into the line and limit breathing.

I'm using one inch tubing to vent the tank up to the fillter neck. It works very, very well. I use big rig nozzles and it takes less than 60 seconds to completely fill the tank. No BS.

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Heath

well i haven't done the mod but i foudn the spot to hold the nozzle to let it go full blow. but you gotta listen to hear the fuel filling the filler neck or it will shoot back at you. prety easy to hear though.

icanfixall

maybe you need to change to 5/8" line to let more air out faster...

hesutton said:

I'm using one inch tubing to vent the tank up to the fillter neck. It works very, very well. I use big rig nozzles and it takes less than 60 seconds to completely fill the tank. No BS.

Heath

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So I take it that reinforced PVC tubing is OK with diesel?

I've picked up everything but the hose to do this mod...hoping to do the rear tank soon, and the front one whenever I get a chance.

ghunt said:

So I take it that reinforced PVC tubing is OK with diesel?

I've picked up everything but the hose to do this mod...hoping to do the rear tank soon, and the front one whenever I get a chance.

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Not really. After three years, the first set leaked. I looked a lot of places to find fuel hose that big, but to no avail. I just replaced it with the same tubing.

Heath

Thanks guys! I did the rear tank this morning with 1/2" hose. Filled up fine, I didnt try the big nozzle though.

I worked on my rear tank filler neck this evening- I was suprised how loosely that inner thing that the hose attaches to is held in there! Might see if I can drop the tank this weekend and do the rest of it. I haven't been able to use my rear tank since I got the truck since the fuel lines going to it are so corroded...hoping to correct that problem.

Hey hesutton, I see that you have that small clear line on your vent tube. Is that a vent tube for the vent tube? Heard mention of that in the writeup, but didn't really understand what the guy meant. What is that black thing it's running to?

ghunt said:

Hey hesutton, I see that you have that small clear line on your vent tube. Is that a vent tube for the vent tube? Heard mention of that in the writeup, but didn't really understand what the guy meant. What is that black thing it's running to?

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That goes to the roll-over valve. I made a canister for the rollover valve and it is mounted up next to the filler neck.

Heath