Since I bought my truck, I have been unable to fill the rear gas tank. When I try to pump fuel, it just fills the neck and then overflows. Looking for some advice on where to start troubleshooting. never worked on the gas tank before so any advice is appreciated, especially for safety. to my knowledge there is no gas in the tank (I have knocked on it and it sounds dry as a bone)

thanks in advance

1991 Ford f150 4x4 I6 Regular Cab

 

Is the filler neck/hose kinked anywhere?