[rockitdoc]

I like the idea of using a manometer to check for fuel tank leaks instead of blowing the tank up with more than 1 psi from my hand pump or 10 hp compressor. Anybody have a picture of how to do this without getting water in the tank?

 

[Desert Rat]

no picture needed.

1. tank elevated
2. clear hose goes down from where it exits tank. Like for example, if the tank is on a workbench, the hose would go down to the floor
3. makes a U turn and goes straight up, next to a ruler, mark on a post, whatever
4. water in hose in the U but NOT so full that it can run into the tank
5. pump enough air into tank to force water up vertical section.
6. mark level
7. check level later. If its gone down more than would be accounted for by barometric pressure changes you have a leak. If it's still hanging out where you left it, good to go.

FYI- As far as pressurizing the tank with a compressor- You're supposed to pump air in through the vans fitting, but also put a party balloon over the fuel vent to act as a pressure relief valve. Whatever psi it takes to blow up a balloon is the max that should be in there during that test, and even then the real test is to douse the outside of the tank with it with soapy water and look for air bubbles seeping out

 

[PilotjohnS]

Same setup

I did the same setup as above, but no party ballon. I put water in my mouth, blew in the hose as much as I could and on the last breath put the water in the hose. The water column held the pressure in the tank with about about 10” of differential.
While the tank was pressurized with the wtaer column, i put soap suds on all the seams and found a leak on the back baffle.

For the repair, i left the water column in place, drilled out some rivets where the leak was, and put a slight vacuum on the tank by spacing the vacuum nozzle away from the tank fuel filler. So the water column showed a slight vacuum. This was enough so that the fresh proseal would be drawn into the seam. Re riveted, tested again with water column for 3 days and soap suds and no more leak. I did the re sealing on a very warm day.

Havent put fuel in the tanks yet, but they held air for a few days. More details in my blog or here under my build section

 

[wirejock]

Manometer

I like the idea of using a manometer to check for fuel tank leaks instead of blowing the tank up with more than 1 psi from my hand pump or 10 hp compressor. Anybody have a picture of how to do this without getting water in the tank?

Terry explained it well. I'll show you also when you get my manometer kit.