Crack in Fuel tank

[grillage]

Is this little fella enough to cause the stank I've been experiencing or should I keep looking?




I already had it fixed while it was out of the car, just curious as it seems like a pretty small crack:

[944 Ecology]

Pressurize the tank while underwater. Bubbles will indicate leaks.

[MJinCO]

Just having repaired the tank from my 924, search for fuel tank leaks/repairs/cracking and you will find one long thorough thread on the forum. That is the traditional area for the steel tanks to crack. Not to be critical, but pressurizing the tank isn't easy, and any repairs are quite difficult, apparently it is basically a design/manufacturing problem with the tank. The apparently best solution from the thread is to use aircraft tank sealants, but my call to the local aircraft mechanic said it is intended for internal use and he had no idea if it would work on the outside and finding someone to solder a patch to the tank(the traditional method)is getting difficult.

I went looking for a flexible, gas resistant sealant and used some stuff called Seal All from the local FLAPS, Permatex and Loctite have similar products. It hasn't been long enough to know if it was successful. I also put and epoxy/kevlar reinforcing patch over the crack(mine was at that metal plug about 3 inches from yours). I also put some epoxy/kevlar reinforcing strips on the flat sections trying to change the flex characteristics of the tank as it is in the shape of a saddle and that area where it cracks has the lowest cross section so is a flex point.

Hope this helps, wish you luck.

[grillage]

Originally Posted by MJinCO

Just having repaired the tank from my 924, search for fuel tank leaks/repairs/cracking and you will find one long thorough thread on the forum. That is the traditional area for the steel tanks to crack. Not to be critical, but pressurizing the tank isn't easy, and any repairs are quite difficult, apparently it is basically a design/manufacturing problem with the tank. The apparently best solution from the thread is to use aircraft tank sealants, but my call to the local aircraft mechanic said it is intended for internal use and he had no idea if it would work on the outside and finding someone to solder a patch to the tank(the traditional method)is getting difficult.

I went looking for a flexible, gas resistant sealant and used some stuff called Seal All from the local FLAPS, Permatex and Loctite have similar products. It hasn't been long enough to know if it was successful. I also put and epoxy/kevlar reinforcing patch over the crack(mine was at that metal plug about 3 inches from yours). I also put some epoxy/kevlar reinforcing strips on the flat sections trying to change the flex characteristics of the tank as it is in the shape of a saddle and that area where it cracks has the lowest cross section so is a flex point.

Hope this helps, wish you luck.

Thanks! I took it to a radiator shop and they soldered the two sides - one with a crack, and the other that could crack.

Getting it all back together today so fingers crossed!

[ERAU944]

The aircraft tank sealant you're looking for is called 'Pro-seal' and it *can* work on the exterior of a tank but the other fellow is correct - it is meant for internal use. It is also meant to work with Avgas so my recommendation would be to create a test article and expose it to mogas and see if there is a reaction/unbonding tendency before trying the fix on the real deal.

https://www.aircraftspruce.com/catalog/appages/proseal09-04493-4.php?gclid=CjwKCAjwjLD4BRAiEiwAg5NBFvukle3OOcDQwU RZFZWhLCnUGemy87dimnHZYdtHxVS4_i_Zx0aA4RoCMT8QAvD_ BwE

If I were to attempt this on my own car I would clear an area about 1" from the crack in all directions of paint and contaminants, apply the Pro-seal, and give it enough time to cure thoroughly before attempting to use. You can then paint over it for corrosion protection.

[grillage]

I got everything together saturday and filled it up with fuel and there was immediately a small puddle from dripping off the top of the tank.

Ugh.

So either there is another leak in the tank other than what was repaired, or there is another leak. Possibly the plastic "expansion tank"?

I looked at the area around the sender and it's dry. so I don't think that's the issue.