Noticed a problem with non NOS fuel filters we all use (wix,Napa,etc)

[Gunfreak25]

Having torn my canisters apart for a deep cleaning, cup, spring, o ring and all I noticed a potential problem for all us deuce owners.

Pictured is a Napa Gold 3540. It’s a 6 micron filter. The cork gaskets on either end, do not seal against the bottom cup in the fuel canisters. Many other fuel filters I see posted here are built the same way.

The original filters from the military in my deuce were absolutely trashed and well past their service life. However you’ll notice they use rubber on the ends. This seals against the bottom cup in the canisters perfectly.

What this means is for those with the metal on metal cork “seal” there is unfiltered fuel getting past the elements.

My solution, add an o ring to the cup or flip it upside down which seals against the cork, you’d just have to make sure it’s centered on the cork.

Furthermore, there is another o ring in the canisters under the cup. Mine were rotten and easily replaced. These keep fuel from leaking past the threaded center shaft.

Just thought I’d share this, someone on another forum found the same issue years ago. https://forums.g503.com/viewtopic.php?t=58024

 

[jasonjc]

Just pop that center metal piece out of the filter. Then it will be metal to cork and not metal to metal. And the cork will swell when its in the fuel. Or depending on filter you can flip the metal parts of the housing over to get a better seal this depends on filter height thought.

 

[Floridianson]

Yea the metal goes the other way when we have cork top filter. On the canister center post almost at the bottom of the shaft is a hole. There is a carter key the goes in it to stop the first washer. Then spring then washer then fiber washer then metal thingy dish up to cut into cork. Then metal thingy on top of filter dish down again cutting into cork and fiber on top of that. Looks like you have the two fiber washers too. So after you install last steel washer on shaft then fiber washer then metal thingy dish / bowl up. On top metal thingy dish / bowl down then fiber washer. If your fiber washers are fitting loose or in bad shape I would think the right size O ring would do the same thing to stop leakage around shaft. Dish / bowl cutting in to cork or the rubber is what we want.

 

[Gunfreak25]

Glad I’m not the only one who noticed this problem then. But I see a lot of youtubers changing filters on trucks with no regard to this small detail. I bought some o rings that will fit on the metal cups to seal but I can see how flipping them would work just as well and really bite into the cork, like you said depending on the swelling of the cork this may be a non issue at all.

I think it’s just another good reason to switch to spin on filters but that will have to wait until next year for me as I’ve replaced and upgraded a lot of stuff already.

 

[Floridianson]

My eyes a going bad and enlarging your pic I see the O rings and the damaged one. Like the blind man that picked up the hammer and saw.

 

[KB944]

Ah-hah, thanks for this discussion. I'm doing my secondary and tertiary fuel filters today on a Deuce I just bought, and I could have sworn the lower cup came out of the housing bowl-up. I was going crazy trying to figure out why the housing wouldn't go up high enough for the upper bolt to bite even though the new filter is exactly the same length as the old one - something was blocking the housing. Now I've taken off the 3rd filter and sure enough, lower cup is bowl-down, so it had the exact issue Gunfreak brought up. I was so sure it was bowl-up since that would make perfect sense with the cut edge of the cup biting in to the cork, but I see no way to make the filter fit that way. (Napa 3512, 7-7/8" long)
I'll go with jasonjc's advice and pop out the metal insert on the filter to expose cork on the inner edge.

 

[87cr250r]

This guy made the same observation back in 1999.

M44-Series Truck Parts Cross-Reference – Mark's Tech Journal

www.nf6x.net

Metal to metal isn't necessarily a bad thing in filters. Even if oil leaks through the gap, dirt will get caught on the edge provided the gap is small enough. There is actually a type of filter that works on this principle called an edge type strainer.

 

[gimpyrobb]

I have a box of new secondary filters with all new Orings included. PM if anyone needs any