The Stovebolt Site Forums The Shop Area Engine Shop fuel pump

Good morning, I am struggling a bit and looking for some help with a 41 235 fuel pump.

I ordered a replacement line for our antique fire truck from the pump to the carb because someone had cut and placed a fuel filter and rubber hose immediately above the manifold. Its been bothering me for a couple years.

Anyways, the new line has brass nuts on the flares while the older one had steel. I have been having a hard time getting it to seal up and not leak, it wasnt dripping fuel, but with a paper towel I could see after shutting it down that there was some seeping.

I eventually got the carb side leak free so all is well there, but I am still having a little trouble down at the outlet of the pump and now I am wondering if there is an issue with the steel outlet fitting there with the old mating surface?

I have done some reading on the forum here about not using sealers which I am currently not using at all anywhere, but there was back and forth on putting sealer on the 1/8-27 threaded into the pump. I dont know if I have NPT or the fuel threaded type that would not need a sealant, or if that steel flared fitting is damaged. I think the leak is now where the 1/8-27 connects into the pump but given its location and how much I struggled with this project, it was hard to tell.

I am thinking of replacing the fitting with a brass one that is a dorman MNPT 1/8-27, but didnt want to damage the pump, or maybe I just need to thread seal that existing end. I wasnt sure, so wanted to see if anyone could make a couple suggestions for me. Thanks so much all!

If the new line came as an assembly with the flare nuts already on the tubing, you have inverted flare fittings. I'm not familiar with the 1941 pump but would expect it to be inverted flair also. Do the new inverted flair nuts match the old ones visually? There is the possibility that the seat in the pump is nicked or rusty but not very likely, the brass nuts should seal quite easily given the soft material although if overtightened they may be distorted. The face of the flair is the sealing surface with flair or inverted flair applications, whereas pipe threads are tapered and the sealing surface is the threads and typically need some type of additional sealer such as liquid sealer or Teflon tape

The usual fuel line configuration is a 1/8" NPT female thread at both the fuel pump and the carburetor with brass or steel adapters threaded into them to convert to either 1/4" or 5/16" OD steel or cupro-nickel tubing with inverted flares at both ends. The flare fittings do not require thread sealer, but the male pipe threads on the adapters can leak if they're not sealed. I use a gasoline resistant brush-on liquid sealer (sparingly) such as Permatex Super 300. Super 300 was developed back in the 1950s to be used on fittings exposed to aviation gasoline, and it's by far the best liquid sealer I've ever used. It's a little difficult to find- - - -I think NAPA stores list it as a special order item, and I can usually find it on Ebay with a little searching. Good luck!

shop.advanceautoparts.com/p/permatex-super-300-form-a-gasket-sealant-non-hardening-4-ounces-80057/7010206-P

Jerry

Jerry - I just did some web searching for sources starting with your link to get "Permatex Super 300". All the listings, including the Advance Auto Parts link, I found showed "out-of-stock' or "not available".

A check of the Permatex main page for the original Part Number 80057 takes me to what is evidently the replacement for the "Super 300", now listed as Permatex® Aviation Form-A-Gasket® No. 3 Sealant Liquid, 4 OZ with the new part number "80019".

My local NAPA lists the "80019" as Permatex Gasket Sealer Form A Gasket Seal and is in stock, ready for pickup.

In case it helps folks "North of the border" in Canada, the Permatex Part No. is "CAN Item # : 58931".

Hope this info helps you and anyone else looking to acquire the product as it looks like the old "Super 300" isn't available any longer.

Thanks for all the replies, I ended up just tightening them down a little better with flared nut wrenches and it seems that has stopped the leakage. I ran it last night and everything is in order which is a great feeling.

Great to hear you got it leak free and thanks for letting us know what took care of the problem.

BTW - I've searched high and low through the forums and can't seem to find a single pictures of your truck. Is this the 1941 (or maybe '42?) 1-1/2 ton Military Fire Truck you've mentioned in previous posts? Would love to see some pictures.

Here are some photos!

That is one absolutely awesome and beautiful Fire Truck sir!!!

I know you've been with Stovebolt for nearly 20 years, but I think it would great if you actually introduced yourself and your truck in the Welcome Centre with pictures and some history on the truck.

Definitely got to be shared IMHO. Maybe even a post in The Stovebolt Volunteer Fire Department as that's also a great place for showing off a very appropriate truck to the forum.

Okay, sorry if I got carried away - lol! Where's my bib - drool, drool, drool!

Aviex #3 is a really poor brush-on sealer that predates Super 300 by several years. +3 is kind of chocolate brown- - - -300 is almost black, and it's a much better sealant. I've used both types for 60+ years, and there's no comparison at all. Too bad they've chosen to discontinue the good stuff!
Jerry