Sealing NPT fuel fittings

[RODRIG3911]

Hello fellas, I had bought the Wildhorses M1A1 fuel tank (Not bashing it at all, it's an amazing tank! Well thought out and fits like a glove) and I've been fighting a leaking issue at the fittings that come out of the pump bracket from the tank. I've already pulled it and reinstalled it 5 times. Obviously I'm doing something wrong! I'm using the permatex high tack as per instructions and this last time I tightened it down so much, the fitting was sitting flush on the pump bracket.... I Ordered 3 new fittings and I'm going to try all over again...

Any good advice for me? Should I use a gas resistant sealer with teflon? How about teflon tape? Any one ever braise the brass fittings on? I'm really feeling defeated brothers and need good advice. I'm ALMOST regretting this upgrade at this point, even though I know it's much better once I figure it out

 

[RODRIG3911]

I was also looking into different pump options for a 4.5" hole with 16 screws as a last resort. Anyone know of one that'll fit that does away with the npt fittings? The sniper fuel pump uses a 3.25" hole. Fitech uses 4.5, but the bolt holes appear different..

 

[Yeller]

for fuel (anything for that matter) with NPT threads I always use this and have yet to have a failure is
https://www.permabond.com/wp-content/uploads/2016/04/LH056_TDS.pdf

 

[RODRIG3911]

One more quick thought..

The pressure at the fitting should be very minimal since the fuel travels inside of the fitting, and the gas just sloshes up to the top of the tank a bit, which creates very low pressure. Could the issue be where the hose clamps in the bottom of the fitting coming from the pump itself, inside the tank? In my mind, it would be the ONLY way to get super high pressure at the service fitting

 

[RODRIG3911]

Thank you Yeller. I'll look into that stuff!

 

[JKH67302]

I have the same tank sitting and waiting for install this fall. I have read that the high tack stuff is not working for most. I did some searching on another forum and its was widely touted as a solution for a gasoline friendly thread sealer. I have not tried it yet so the other suggestion might be better. However I'm curious what you end up using and how it works out. Please report back!

https://www.amazon.com/dp/B004NNVQ1M/ref=cm_sw_r_cp_apa_i_Z5suFb9V2GG8W

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[RODRIG3911]

I have the same tank sitting and waiting for install this fall. I have read that the high tack stuff is not working for most. I did some searching on another forum and its was widely touted as a solution for a gasoline friendly thread sealer. I have not tried it yet so the other suggestion might be better. However I'm curious what you end up using and how it works out. Please report back!

https://www.amazon.com/dp/B004NNVQ1M/ref=cm_sw_r_cp_apa_i_Z5suFb9V2GG8W

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Hey, a fellow Wildcat fan and Tucsonian ;D!! Thanks for that link. I had seen that stuff pop up in my searches for gas friendly pipe sealer. I Actually ordered this stuff that looks similar earlier in the week and have been waiting for delivery(Wanted to pick the brains on here before using anything) https://www.amazon.com/gp/product/B0049D60I0/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1.
I'll probably try the Earls stuff first since I'll have it Saturday, and either the Permabond stuff Yeller recommended or the Gasoila stuff you mentioned If the Earls stuff doesn't work. I went to look for the Permabond stuff and Ace earlier and they don't carry it..

PS
Are you on our Classic Broncos of Tucson site yet?
https://www.facebook.com/groups/ClassicBroncosofTucson
I'm Joel with the Blue Bronco. Not sure if we've met before

 

[toddz69]

My tank's still sitting on the floor of my shop but I did get partially completed with the assembly last year before life took over again.. I did a bunch of research online because I wasn't crazy about the high-tack stuff either and kept finding this stuff recommended by a bunch of OCD aircraft types:

https://www.permatex.com/products/g...x-aviation-form-a-gasket-no-3-sealant-liquid/

I guess I should put some liquid in my tank one of these days and see if it works or not...

Todd Z.

 

[EPB72]

My tank's still sitting on the floor of my shop but I did get partially completed with the assembly last year before life took over again.. I did a bunch of research online because I wasn't crazy about the high-tack stuff either and kept finding this stuff recommended by a bunch of OCD aircraft types:

https://www.permatex.com/products/g...x-aviation-form-a-gasket-no-3-sealant-liquid/

I guess I should put some liquid in my tank one of these days and see if it works or not...

Todd Z.

Todd for thread sealant I wouldn't use hi tack or the aviation sealant you posted the link to .. I've tried both over the years without luck as well as a coworker {older timer} that used the aviation sealant alot, Then seeing some repeat reseal jobs where the aviation sealant was used on both threads and as a gasket dressing,my .02 cents............https://www.permatex.com/products/t...nts/permatex-high-performance-thread-sealant/ for thread sealant this is what I use,,

 

[RODRIG3911]

Looks like a teflon paste seems to be the most recommended... I got 2 nice long trips out of my high tack sealed fitting before they leaked.. Wildhorses Jim, Paul, Mitch have you all had 100% leak free installs with the permatex high tack? One thing I was doing that might have been wrong was tightening, backing out, tightening again, and backing up like we do with brake lines to get them tightened further. Might have been part of my issue... I can't wait to get this this in and working right. When It was working on those 2 trips, my sniper EFI seemed happier around curves

 

[toddz69]

Todd for thread sealant I wouldn't use hi tack or the aviation sealant you posted the link to .. I've tried both over the years without luck as well as a coworker {older timer} that used the aviation sealant alot, Then seeing some repeat reseal jobs where the aviation sealant was used on both threads and as a gasket dressing,my .02 cents............https://www.permatex.com/products/t...nts/permatex-high-performance-thread-sealant/ for thread sealant this is what I use,,

Thanks for the recommendation! My Bronco wouldn't be my Bronco if I didn't rework something 3 times on it so I'll switch to that stuff. It appears to be similar to the ARP Thread sealant I have so maybe that would work fine too.

It's unfortunate that we're even dealing with NPT fittings in a fuel system.

Todd Z.

 

[bmc69]

Todd for thread sealant I wouldn't use hi tack or the aviation sealant you posted the link to .. I've tried both over the years without luck as well as a coworker {older timer} that used the aviation sealant alot, Then seeing some repeat reseal jobs where the aviation sealant was used on both threads and as a gasket dressing,my .02 cents............https://www.permatex.com/products/t...nts/permatex-high-performance-thread-sealant/ for thread sealant this is what I use,,

That is exactly what we use here in my shop for all but the very high pressure (2000 psi and up) NPT connections; for those we use a Loctite HP thread sealing product that comes in "lipstick" form. Generally though, we try hard to avoid using NPT at all...but not all products come with SAE o-ring ports..

 

[bmc69]

It's unfortunate that we're even dealing with NPT fittings in a fuel system.

Todd Z.

That.

We build hydraulic systems for marine application and try hard to avoid including any NPT connections. Hard to avoid them for some of the larger low-pressure connections but we avoid them almost entirely for anything on the high pressure side.

 

[toddz69]

That is exactly what we use here in my shop for all but the very high pressure (2000 psi and up) NPT connections; for those we use a Loctite HP thread sealing product that comes in "lipstick" form. Generally though, we try hard to avoid using NPT at all...but not all products come with SAE o-ring ports..

OK - and another golden recommendation I'm looking for!

Todd Z.

 

[JKH67302]

Beardown Joel! I don't think we have met but ill check out the Facebook stuff. Nice to meet ya!

We've talked a lot about the NPT threads, but how does the other parts seal up using the high tack? Does the sender itself seem to be free from leaks?

James

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[RODRIG3911]

Thanks for all your in put guys!! I'm lucky enough that Hose Power USA is located in my town (The make all kinds of high pressure hose and sell the sealants for them) and went to pick their brain today. They told me confidently that Gasoila sealant is what I need, so I bought a can from them.

Last week I had also ordered a 6" 16 hole Viton gasket to replace my now jacked up cork one (For that, I still plan on using permatex high tack). I'm also going to replace the 5/16th efi hose that goes inside the pump to the fitting. I think after messing with mine so much it may no longer be sealing right either.

James nice to meet you on here man! We'll have to meet up for a Bronco ride sometime..... Good question, my sending unit didn't appear to be leaking, but I'll definitely keep that in mind if I continue having issues

 

[RODRIG3911]

Here's the new fittings and part numbers

 

[jamesroney]

I was also looking into different pump options for a 4.5" hole with 16 screws as a last resort. Anyone know of one that'll fit that does away with the npt fittings? The sniper fuel pump uses a 3.25" hole. Fitech uses 4.5, but the bolt holes appear different..

I used the Tanks, INC fuel pump stand and plate in a northwest Fab tank. I like the northwest tank, because it sits higher than the strut mounted tanks. But I don’t like their EFI tanks, because they leak at the gasket.

The Tanks Inc fuel pump stand uses 1/4 NPT female fittings. I wrap the fittings with PTFE tape, and they don’t leak. Or at least if they leak today, they don’t leak tomorrow.

 

[RODRIG3911]

I used the Tanks, INC fuel pump stand and plate in a northwest Fab tank. I like the northwest tank, because it sits higher than the strut mounted tanks. But I don’t like their EFI tanks, because they leak at the gasket.

The Tanks Inc fuel pump stand uses 1/4 NPT female fittings. I wrap the fittings with PTFE tape, and they don’t leak. Or at least if they leak today, they don’t leak tomorrow.

Looks like the plate and stand m1a1 uses. I hope you stay leak free! I got mine put back together. Going to wait for it to cure before trying it out again

 

[RODRIG3911]

So a little after action review...

I hate to jinx it lol, but the Gasoila and new gasket worked!! Went on a long cruise and even added like 17 gallons of fuel. The Bronco ran like a champ and the only leak I had was at my fuel pressure gauge. Tightened that up and all is fantastic again!!

I like this tank and recommend it, but I'd stay away from permatex on the fittings (Use it on the gasket and bolts for sure) instead use a gas proof sealant that doesn't dry like Gasoila. After reading all your post, it seems like there's more then one good way to do it, but for sure those NPT fittings are finicky