Does anyone know why the 75 gas tank has lining inside? It's made of rubber too I think. Doesn't the lining reduce the volume of the tank? Could this be part of the problem I'm having with my gas guage, i.e., not reading the right amount?

Thanks for any info.

The rubber lining is called a bladder and is for safety purposes. In case of a rear end accident it is supposed to keep the gasoline from leaking out very fast and creating a fire. I think 75 had the first bladder, and in 78 they made a better one out of high density poly-ethylene.