If the components of a gear type pump are severely worn and spare are not available then, the rotor type pump can be provided. After taking out the used oil pump, you shall also have to take out the pivot pin, washer, and plug as well. Subsequently, place the sealing washer and then tighten the pipe with the help of a new pivot pin and lock washer which should be bought along with the new pump. Last of all, fit the new rotor type pump, sprocket and 24 link chain and if required fit a shim while ensuring that the same is aligned to the oil hole such that the driving chain will be just deflecting with light pressure applied by the thumb.