Fuel System: Trouble stopping gas leak exiting tank

[64V19816]

Why do have so much difficulty stopping gas weeping out of the gas outlet/rubber fuel line union? This is using new 5/16 rubber fuel line and two hose clamps. Is there a secret here? Or is New 5/16 fuel hose larger in diameter than needs to be?

[sweetolbob]

Why do have so much difficulty stopping gas weeping out of the gas outlet/rubber fuel line union? This is using new 5/16 rubber fuel line and two hose clamps. Is there a secret here? Or is New 5/16 fuel hose larger in diameter than needs to be?

If you are using the newer FI hose it's harder to clamp so if you are using two clamps on each end, be sure they are clocked about 180 apart and if it's still an issue try some sealant like this. I suspect you know this but don't use silicone. I'd start with a new piece of hose also.

[rockne10]

And, if you are using the new stainless worm screw hose clamps, I've found you can get them much tighter with a nut driver or ¼" ratchet and socket than with a screw driver.

[64V19816]

The fuel outlet pipe is .312 and 8mm hose is .315. Ive got two cars with this same leak. Both have new hose and two tight clamps. Was OEM fuel tube narrower?

[Greenstude]

Is it possible to get hose very slightly smaller than the pipe, so that it would need to be forced on and make a tight fit?

[JoeHall]

About 20 years ago I replaced all Studebaker rubber fuel lines with the newer stuff for fuel injection, and have not experienced any problems. But about 30 years ago, I had a tank fuel nipple begin to leak where it is silver soldered to the tank. I used JB Weld to seal it, and had to re-do the job about every 1-2 years, till I finally removed and repaired the tank. To the OP, are you sure yours is not leaking where the nipple goes into the tank? If it's leaking there and running forward to the rubber line, it would be difficult to discern from the rubber line leaking.

[64V19816]

It soldering looks good. I’m thinking my troubles are from the cheap hose clamps getting egg shaped from tightening on that spongy rubber. I got different clamps, made for fuel injection and they tighten much more circular. Will try that today.

[JoeHall]

It soldering looks good. I’m thinking my troubles are from the cheap hose clamps getting egg shaped from tightening on that spongy rubber. I got different clamps, made for fuel injection and they tighten much more circular. Will try that today.

I use the newer, FI type clamps on everything. Definitely superior to the old type which, as you say, tend to become oblong, especially in small diameter applications. If in doubt, you can also double up on the clamps, plant of room for two of them there.

[altair]

I have a tank off a 63 Lark and the outlet pipe is .325 therefore a 5/16 (.312)ID rubber tube should fit tight and not leak with no clamps. Originally there was no clamp on the rubber tube, but the rubber completely detreated to mush from the alcohol gas.

[altair]

I think you should try an imperial diameter hose 8mm is too big. If your outlet is .312 then a .300 rubber tube should fit. That same size rubber tube is used on the vent pipe on Lark type cars the ID is .300 therefore it would be a tight friction fit and possibly no clamp would be needed.

[64V19816]

Driving me crazy. This should Not be so damn difficult and I’m ready to scream. I forced a thin plastic tube over the outlet and really worked hard forcing the fuel hose on, used two injection clamps... and Still the drip drip drip. Put my finger over the end of the pipe it stops.•••••no stores are open here but I think I’ll try 1/4” line, The outlet pipe itself seems “rough”, maybe rust corrosion, I’ve sanded it some but maybe the fuel weeps out through this corrosion? Smear pipe when dry with JB and sand smooth?

[doofus]

64V, sounds like you have hit on the answer. i did this to a problem nipple,sanded well and cleaned then added heat shrink tubing to cover nipples entire length. lasted for years. Luck Doofus

[64V19816]

The answer to the fuel leak was finally; permatex smeared on tank outlet tube, a short section of 1/4” fuel hose well forced onto the outlet tube to a 1/4” to 8mm stepup, then that into the new 8mm fuel line, Small wide fuel injection clamps. For the heck of it I applied more permatex to the unions and over the end of the hose to tank. .....a few weeks in, it has all held.

[sweetolbob]

Permatex - never be without it when working on auto mechanical parts. Glad you solved the leaking issue.

Bob