An old fire truck is beginning to look like the 550 I drove over a half a century ago. I took the axles and the rest of the air brake stuff out of an old LCF parts truck. I mounted a Fontain 5th wheel of the era the way we did it back then. U-bolts and a 2x4 for a cushion. Not DOT legal any more, but I want it to be the way we did it. The fuel tanks are just dummies. 100 gallons of gas would get stale on me. I thought a pickup tank would fit behind the seat, but the larger original tank is several inches taller and the fill neck doesn't fit. The hole in the cab is higher than a pickup and I didn't want to deal with that. I mounted a spun aluminum tank behind the seat. I have to flop the seat forward to fill it, but that's OK.
https://photos.google.com/share/AF1...aWRyU1NYNnRCZ09OVElhckdEelNLbXNobjlnTnNnThe tubeless tires are coming off in favor of 10.00x20 tube required like I ran on my old GMC. I bought a trailer from Saunders Leasing in 1967 that had tubeless tires and I have been running tubeless ever since.