I have a Cat 22 that probably has not run in 20 or more years. I cant  get the fuel tank open. I have tried PB Blaster and Liquid wrench with no luck. I gave up on the big pipe wrench before I ripped the spout out of the tank.  I really dont want to take a heating torch to it and maybe blow myself up. Any other ideas???       Grant.

you could try a needle scaler on low pressure. some times you need to do something up first to get it to undo

I had not thought of using the needle scaler. My go to is typically heat but a torch and a gas tank dont go well together. I will give it some "Good Vibrations" this week.

Thanks Grant.

Any rusty parts the vibration method can work wonders. Using 2 hammers one bucking and one hitting with the other works great on pipes. Or this tank cap.

Hi, Grantj.
Sometimes with things like fuel caps or pipe fittings, or well exposed nuts, freezing them or at least applying some form of severe cooling will help - takes time to chill the offender and then let it warm up again to ambient temp. but it tightens the outer fitting on the inner part and then lets it expand again - creates compression and then release. Dry ice works well or simply packing ice around it can do the trick.

It'z sorta the reverse of freezing a track master pin to make it go in easier.

Just my 0.02.

I will try all of the above. They make sense to me. Thanks.

the two hammer trick is how most steering joints are done if you dont have a joint separator. the second hammer acts sort of like a mirror and gets the hit to bounce back.

I use a 1500 watt heat gun when i don't want an open flame

I think you could get a heater band to just about fit that. Get it cherry red for you. And I must tell all I have never used ice, but I think I like heat the better.