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Fuel Filler Neck Mod

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29K views 20 replies 14 participants last post by  Patrick Feeley  
#1 ·
I've read a couple different ways to do this and was wondering what the most common way was for everyone that has done this mod. I've already bought 2: 5/8" plastic elbows with 1/2" threads, and 2: 5/8" brass hose barbs with 1/2" threads. I need to know what type of hose to use. Will 5/8" heater hose work, or does it need to be fuel line? Do you use just the brass hose barb in the filler neck without an elbow? Do you drill out the factory rollover valve to accept the plastic elbow fitting? I'm getting ready to remove the bed and replace it with a flatbed so I figured this would be the perfect time to do this mod.
Thanks
 
#2 ·
Heater hose probably wont work for very long. The fuel will eat it up. Napa sells a multi purpose hose that is rated for diesel and oil, but it's expensive. I just used some 3/4" clear vinyl hose from Ace hardware. It's been there for around 3 years so far with no deterioration . I used straight hose barbs in the filler necks, drilled and tapped and then coated with JBWeld. Pay close attention to how you route your hoses,you should have a downward slope all the way from the neck to the tank. If it sags, the low spot will fill with fuel and the tank won't vent. I used the rollover valves from an OBS F-superduty, they are the same outer diameter and fit the same grommet as ours but are barbed for 3/4 hose.
 
#3 ·
Thanks for the reply. I will get some clear hose today, and it sounds like I need to buy a tap for the hose fittings.
 
#4 ·
I really wouldnt bother spending the money for the tap. The neck is so thin there's not much metal to cut threads into. I have an aux tank in the bed that I have vented into the front tank with 3/8 tubing. I just drilled the neck and screwed the brass fitting in and it fits about the same as the other barb that was tapped into the neck. Both of them required JBWeld for a secure connection. If you have access to a torch and some brazing rod I think that would be the best way to do it.
 
#5 ·
Ok, I won't waste my money on the tap. I'll have to cut my filler necks to install the flatbed, so it should be pretty easy to seal the fittings in the neck.
Thanks again.
 
#6 ·
Bluemule, you wouldn't happen to have the p/n for those rollover valves would ya? I ordered the p/n off of dzljims site and it is no longer available and all the ones the salesman at ford brought out were too small on the barb end.
 
#7 ·
www.powerstrokeshop.com shows it as still being a good p/n, $17.93 ea.

I did the neck when I put in the rear tank, I used solder and a propane torch for all the joints. Works well so far.
 
#9 ·
I see dzljim says that the caps vent the tanks. Since that is true why not connect the tanks together, and leave the caps open during fueling, then the tanks could vent through each other. Any thoughts on this?
 
#10 ·
I used the 1/2NPT with 5/8 barb fitting. Once you drill a 7/8 hole in the filler neck, you a 1/2 electrical locknut to tighten down the fitting. I then put JB Weld over the locknut and fitting.

I sit am using the plain 'ole heater hose for 6 years now. It turned gummy. Bought some 5/8 fuel line hose but never did the change over.

Billy T.
gnxtc2@aol.com
 
#11 ·
Well I got my original bed off. I removed the rollover valves and got some 3/4" thread 5/8" barb elbow fittings instead of the 1/2" thread ones. I screwed the fittings right into the grommet for the rollover valve and they tightend up and fit very well. I didn't have to file the threads down and make a groove in them to set in the grommet better. Maybe tommorrow I'll get my flatbed installed and figure out where I need to cut my filler necks so I can get the fittings installed in them and finish this project. Does anyone want me to take pics of this while I have my bed off so they can be used as references to this subject?
 
#12 ·
[ QUOTE ]
Well I got my original bed off. I removed the rollover valves and got some 3/4" thread 5/8" barb elbow fittings instead of the 1/2" thread ones. I screwed the fittings right into the grommet for the rollover valve and they tightend up and fit very well. I didn't have to file the threads down and make a groove in them to set in the grommet better. Maybe tommorrow I'll get my flatbed installed and figure out where I need to cut my filler necks so I can get the fittings installed in them and finish this project. Does anyone want me to take pics of this while I have my bed off so they can be used as references to this subject?

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Most definitely...I am on the verge of doing this myself...20 minute fillups are getting a little old...I get mean looks from guys waiting behind me as they watch me top off the tanks .000001 gallons at a time...haha /ubbthreads/images/graemlins/grin.gif
 
#13 ·
A quicky band aid is to pull the tank fill hose out of the tank and cut the inside vent hose level with the top of the fuel tank. I think the SD guys called this "harpooning". Works better than stock although not as good as installing the the TransferFlowlnc kit or doing the tank mod.
 
#14 ·
The smaller inside hose is not the vent, but the actual fill hose, with venting going between the small and larger outside hose. That being said, I did do this and it does help for sure. Super Duty guys have two hoses that enter at two seperate places in the tank, and they cut them both off flush, that is the harpoon.
 
#15 ·
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Does anyone want me to take pics of this while I have my bed off so they can be used as references to this subject?

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If it is not too late and you don't mind going to the trouble I'd like to see some pics as I'm pretty green when it comes to DIY...
 
#16 ·
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. Works better than stock although not as good as installing the the TransferFlowlnc kit or doing the tank mod.

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Gotta admit the Transfer Flow filler neck is great. The vent on the stock neck is a narrow slit. Transfer Flow's vent is 3/8" round. Fuel splash back and forever fill ups are a thing of the past.
 
#17 ·
[ QUOTE ]
Well I got my original bed off. I removed the rollover valves and got some 3/4" thread 5/8" barb elbow fittings instead of the 1/2" thread ones. I screwed the fittings right into the grommet for the rollover valve and they tightend up and fit very well. I didn't have to file the threads down and make a groove in them to set in the grommet better. Maybe tommorrow I'll get my flatbed installed and figure out where I need to cut my filler necks so I can get the fittings installed in them and finish this project. Does anyone want me to take pics of this while I have my bed off so they can be used as references to this subject?

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Was going to mention this but see you figured it out.
You can modify both tanks for the cost of one roll over valve from Ford with the WATTS 3/4"NPT x 5/8" Hose Barb nylon elbow. It does screw right into the grommet and works great. Picked mine up at the local hardware and the other one at HomeDepot.
 
#18 ·
Well I got the bed installed and all the fittings and hose finished for the filler necks. I didn't get any pics with the bed off. /ubbthreads/images/graemlins/shrug.gif I was going to take them but it was one of those days when nothing went right including mounting the bed, that turned out to be about a 6 hour job. /ubbthreads/images/graemlins/mad.gif I still think I got a few good pics that would be able to help someone else wanting to do this mod. The main difference with the way I did mine is you won't want to cut your filler necks like mine unless your planning on installing a flatbed. If anyone would like some different pics let me know and I will take them.
Filler Neck Pics
 
#20 ·
I think I missed somethign with this thread...what fill neck mod are we talking about? The fast flow fill or filling dual tanks with one fill neck?

I'd love to see pics (can't see the ones listed for some reason, might be too old). I'm putting in the Aero spare tire tank and would like to have both fill necks in the same location similar to the FJ80 setup for Toyota...anyone done this?
 
#21 ·
It would be for the fast flow mod (on each filler neck separately). Cheers!