Remove the distributor cap . Before removing the distributor (See Removing and refitting the distributor ), mark the position of the rotor arm so that you can refit it just as it was.
You have to consider the speed at which the shaft will be moving, the housing bore, and the runout. These are important to make sure that you choose an oil seal that will not be exposed to unconducive abrasions.
The mechanical seal is used in a pump, mixer and other mechanical engineering scenarios to contain the fluid within a vessel where a shaft rotates through a stationary (or rotating) housing.
5. TYPES OF FLUID: Numerous oil seals can interact with oils, fuels, grease, water and more. However, know exactly what type of fluid the rotary shaft seal will be in contact with will ensure the longevity of the seal and the machinery.
EPDM

In this kind of seal, wider tolerances are possible between the OD of the seal and the seal housing. Irregularities of the housing surface can be taken up by the resilient rubber layer on the outside of the seal. However, the rubber covered seal can be blown out under high pressure in a reciprocating application whereas, with a metal case, there is no such danger.
The allowable total eccentricity is the maximum total eccentricity at which the sealing edge can accommodate shaft rotation and retain adequate sealing performance. The oil seal's allowable total eccentricity is affected by the design of the oil seal, the accuracy of the shaft, and the operating conditions.
In this blog, we attempt to highlight what are Oil Seals and the various Rotary Shaft Seals including Mechanical Face Seals, Water Pump Seals, Gland Packings, and V-Seals that are readily available.