Removing Chassis mounted Petrol Tank in +4 and 4/4 roadsters

It is rare that you get to work on an older Morgan that has not already been buggered by well meaning or incompetent previous owners. With that in mind, if you find yourself with a leaking gas tank or you just want to remove it to clean and de-rust its environs, be prepared to make an appointment with Mr. Sawzall.

When the car left the factory the gas (or petrol if you prefer) tank was supported between the lower flanges of the chassis rails by two ash planks. The boards were four quarters thick, minimally dressed and pretty rough. Most likely they were probably chunks of wood that were unusable for anything else. The boards were not equal width and they were strapped together by two 3/4″ wide steel strips screwed to the underside. The strapped together boards were fastened into the chassis by three 1/4″ diameter carriage bolts with torque washers under the head. Lock washers and square nuts completed the assembly underneath. The tank is fastened by four hex-head cap screws from the top through a reinforcing plate under the boards.

Because the boards are so tatty it is not uncommon to assume the end cuts, which are not square, were unintentional. Most restorers, including myself for many years, replace the factory boards with a single piece of plywood as an “improvement”.  Wrong. A rectangular platform, whether of plywood or solid lumber cannot be removed without removing a spring.TANKBOARDS

The factory intended for the tank to be removed from the bottom by removing the three carriage bolts, the two straps, and the four tank screws. The non-square end cuts (approximately 10° making the board a parallelogram) allow the boards to be rotated until they clear the bottom flange rails and drop out. It is not necessary to remove the springs or bumper hangers.

Another subtlety that is often missed, particularly when drilling holes in a new chassis, is that the two forward carriage bolts are located very near the bend in the rail flange rather than being centered on the flange. This is intentional. It allows the carriage bolts to clear the springs for removal.

gas tank installed, '64 +4 four seater
gas tank installed, ’64 +4 four seater

Eventually all gas tanks have to be removed. If you are not the first to do it… well; happy sawing.