This plain nut is from the body parts section in the Rolls-Royce & Bentley parts catalogue for models built between 1956 to 1965.
This nut has a number of uses within the car such as the nut for the main bolt of the mounting bracket, one of the nuts for the flywheel to crankshaft or the nut for the propshaft centre bearing support.
Whenever you fit a car part - or fix any material for that matter - using a combination of nuts and bolts, washers should always be used. It is not merely a cosmetic accessory, instead it actually performs two functions, the first being to protect the metalwork from being damaged due to the tightness of the nut, and secondly to provide a smooth, flat surface so that the nut and bolt stay done up tightly or as long as possible.
All our parts branded Prestige Parts have a 3 year warranty.