New owner fuel tank question

[beeryboats]

I just bought a KF IV that's been setting for 10 years. I stumbled across a post about fuel smells and some sort of tank issue. My plane has evidence of a tank or line issue at the upper aft corner of the right door. I have not had time to work on it yet as my truck needs attention first. But I'm getting confused as to what issues I may find with 1991 vintage tanks. I just emailed the former owner as to what fuel he was using, so I hope to have that info tomorrow. Some posts I read are related to some sort of release agent coming off, and some are about tanks coming apart inside. Can anyone give me an idea of what I should be looking for?

[HighWing]

I have experienced the same symptoms on my first Model IV.. I would first check to see if there is any seepage at the fittings at the tank outlet. The outer bushing that actually mates to the tank can leak as it is brass to fiberglass interface. That bushing is actually a finger strainer to catch large particles before they enter a fuel filter. Also most early fuel hose will allow vapors to escape through the hose. New non permeable hose is on the market. Others will offer leads on that. However, since that area is also the low point on the wing root, any leakage of the tank itself would manifest it as fuel odor in that area.

[t j]

To test for leaks before filling with fuel:

Attach a balloon to the fuel cap vent and clamp all the hoses except one closed. Blow into the open hose...with lung pressure only...until the balloon inflates. Clamp the hose shut and check for leaks around the fittings with soapy water applied with a small paint brush. Dish soap works well. You won't be able to check all the seams in the tank but if the balloon doesn't lose pressure you will be pretty sure fuel won't come showering out when you do fill it.

As said above, the stain on the door at the rear is often due to a leaky quick drain sump valve.

This photo is before I installed the tank.
Fuel tank leak test.jpg

[beeryboats]

[quote=t j;34500]To test for leaks before filling with fuel:

Attach a balloon to the fuel cap vent and clamp all the hoses except one closed. Blow into the open hose...with lung pressure only...until the balloon inflates. Clamp the hose shut and check for leaks around the fittings with soapy water applied with a small paint brush. Dish soap works well. You won't be able to check all the seams in the tank but if the balloon doesn't lose pressure you will be pretty sure fuel won't come showering out when you do fill it.

As said above, the stain on the door at the rear is often due to a leaky quick drain sump valve.

Oh, that was so smart to leak check before installing the tank. I never would have thought of that. I would have built it into the wing thinking it was pressure tested at the factory all fat dumb and happy.

[cap01]

highly recommended to pressure check before its installed . i had one that leaked , pure luck that i caught it before i installed it . happened to notice the bottom was wet while i was sloshing it to clean it out . the mcbeans , the standup people that they are , made it right .