Engine/Transmission (1998.5 - 2002) AN fitting adaptors and O-rings

[Gordon Maney]

I got a big line kit from the nice folks at Vulcan, along with a line kit that runs from the tank to the filter. In that line I installed my Raptor pump.

In studying the way the AN fittings connect to the filter housing it is not clear to me that there is enough crush in the O-rings to make it work. I have a leak I can't figure out, yet am not seeing it leak from a specific site. It just drips from the bottom of the truck.

I have the original supply line still in place, ends open. I can imagine fuel coming out of that, but can't imagine the line could hold as much as I have lost. Yet, I lie under it as it runs and can't see it leaking.

Thoughts?

 

[JCyrbok]

I got a big line kit from the nice folks at Vulcan, along with a line kit that runs from the tank to the filter. In that line I installed my Raptor pump.



In studying the way the AN fittings connect to the filter housing it is not clear to me that there is enough crush in the O-rings to make it work. I have a leak I can't figure out, yet am not seeing it leak from a specific site. It just drips from the bottom of the truck.



I have the original supply line still in place, ends open. I can imagine fuel coming out of that, but can't imagine the line could hold as much as I have lost. Yet, I lie under it as it runs and can't see it leaking.



Thoughts?

If you think that it is coming from the pipe threads where the -AN fitting threads into the housing, just put some Permatex#2 on the threads of the fitting and reinstall. I havent found a fitting yet that leaks after doing that. I have not seen any -AN fittings that use o-rings on them. Got a pic?



Or are you calling the rubber/metal bango washers o-rings? If so you shouldnt need to put banjo washers on, just use the Permatex.



FYI when I changed out my fuel lines to Braided when I did my FASS but I left the stock fuel line in place it leaked maybe 3 gallons of diesel over the course of a couple of days (first night there was a fuel spot aprox 2x2ft under my truck) but it was leaking back by the tank. I blew the rest out with compressed air and it has been fine. Might try that first?





J-

 

[Gordon Maney]

If you think that it is coming from the pipe threads where the -AN fitting threads into the housing, just put some Permatex#2 on the threads of the fitting and reinstall. I havent found a fitting yet that leaks after doing that. I have not seen any -AN fittings that use o-rings on them. Got a pic?

They are not pipe threads. Pipe threads are tapered and seal from interference. Consider the banjo bolts that go in those holes; they are not pipe threads, they are straight threads.

The O-ring is on the part of the fitting assembly that screws into the filter housing.

Or are you calling the rubber/metal bango washers o-rings? If so you shouldn't need to put banjo washers on, just use the Permatex.

No, I am not.

FYI when I changed out my fuel lines to Braided when I did my FASS but I left the stock fuel line in place it leaked maybe 3 gallons of diesel over the course of a couple of days (first night there was a fuel spot aprox 2x2ft under my truck) but it was leaking back by the tank. I blew the rest out with compressed air and it has been fine. Might try that first?

If you do the math you will see that a line of that diameter, that long, could not hold 3 gallons. I am uncertain if that has been the source of my wet spots, but I believe the wet spots would take more fuel than what that line could hold.

After removing both fittings, making certain to maintain correct position relationships between the flat washers and the O-rings, it does not leak now.

 

[JCyrbok]

They are not pipe threads. Pipe threads are tapered and seal from interference. Consider the banjo bolts that go in those holes; they are not pipe threads, they are straight threads.



The O-ring is on the part of the fitting assembly that screws into the filter housing.



No, I am not.



If you do the math you will see that a line of that diameter, that long, could not hold 3 gallons. I am uncertain if that has been the source of my wet spots, but I believe the wet spots would take more fuel than what that line could hold.



After removing both fittings, making certain to maintain correct position relationships between the flat washers and the O-rings, it does not leak now.

well looks like you figured it out.



J-