The Stovebolt Site Forums The Shop Area Engine Shop 57 3100 gas tank sender gasket leak?

What is the best way to keep a original style / repro gas tank and sender unit from leaking?

I have a new tank and gasket and new sender and have just spent $75 on fixing some leaks around the gas tank neck as a result of damag in shipping but there are still some leaks from the rubber gasket around some of the screws (on the sending unit on the top of the tank) when they presure tested it.

Is there a really good gasket sealant I should use that has worked well for you guys in the past and stays somewhat plyable so it will last a few years and not leak?

Or should I just use some Permatex products like fuel-resistant (#2, #3 Aviation, Super 300) ?

Permatex_Aviation_Form-A-Gasket_No_3_Sealant which resists gasoline, oil and grease?

I am concerned that it says resists and not fuel or gasolene proof.

Permatex® High Tack™ Gasket Sealant also says resists gasolene.

What about "Permatex® Hylomar® Universal Blue Racing Formula Gasket Dressing & Flange Sealant" It says: "Suggested Applications: Thermostat housings, differential coverings, hydraulic drives and motors, gearbox assemblies, intake manifold assemblies, oil, fuel and water pump housings and seals, fuel injectors and fuel pumps, transmission and torque converter seals"


What have you used with success on ruber type gaskets on gas tanks?


And how did you apply it?

don't know how high a pressure they used, but keep in mind the tank is not pressurized in use .... I'd just put a dab of any good RTV or gasket maker on the holes before installing the screws, or at most wipe a light layer of sealer on the underside of the rubber seal

Bill

Ok thanks. Do you know if it is the normal practice to just assemble it with only the rubber gasket and no RTV or sealer of any sort?

My old tank and sender had some sort of goop slathered all over it at some point. It was all hardened and had run down the side of the tank. But it was a sealent of some sort.

What did they do from the factory???

What should I do to make keep it from possibly leaking?

When I did a simple presure test with my mouth blowing air into the filler vent tube and holding a finger over the filler tube and over the sender tube it seemed to hold pressure fine. Well like a couple minutes and then my mouth and tongue got tired! Then it al blew out when I released.

And if I do the same on the gas cap it seems to vent at a lower presure than that so I would think it would not leak unless the pressure got really high really fast and the cap could not release it.

Thoughts??

can't say I've noticed any tanks that had what appeared to be sealer, most I've found had cork gaskets that came off easily .... I wouldn't worry much about leaks from the sender and haven't used any sealer there, the only time liquid will actually push against the top will be when you fill the tank til it's up the filler neck, bad practice as temperature expansion will run it out the filler and ruin your paint .... fumes are the problem and the fumes some complain about in the cab are most always from the hose connections on the fill and vent tubes, make sure those fit properly and are tightened well - as for "the pressure getting really high really fast", how could that happen? the tank isn't pressurized, when the fuel gets sucked to the engine, it needs air in from the vented cap, a plugged cap would make for a negative pressure that'd pull air in any leaks and/or cause fuel starvation

Bill