The petrol tank rear mounting bolt is important as it is a special stepped bolt with a long, unthreaded shank that passes through rubber mounting washers.
This bolt is applicable to 1963-1966 Triumph 6T, TR6, T120s
The stepped bolt has a special profile that allows it to pass through the petrol tank mounting hardware to secure the rear of the tank. The bolt is 1-1/2″ long and has 5/16-26 TPI CEI threads.
The bolt is used in conjunction with a cupped washer, rubber washer, and a double-spigot rubber to comprise the rear tank mounting assembly.
The petrol tank mounting bolt captures the rubbers and cupped washer and passes through the assembly. It is bolted directly to the tank mounting boss cast into the frame.