Gaskets - always replace used gaskets with new gaskets. Never use the same gasket twice. Be sure that gasket holes match up with holes in the mating part.
- Serious damage to the vehicle can result if any holes on the flanges are blocked by the gasket.
Lip type seals - Lip seals are used to seal oil or grease. To seal in oil, the lip is installed facing toward oil to be sealed. To seal grease, the lip usually faces away from grease.
- Seals should not be removed. Only remove seals to get at other parts or if the seal is damaged or worn.
- Leaking oil or grease usually means that a seal is damaged and needs to be replaced. Replace leaking seals so that bearings don't overheat. Do not use the same seal twice.
O-Rings (preformed packings) - O-rings should always be replaced if they are removed from the mated part. To prevent leaks, put a coating of the same lubricant being sealed on O-rings before putting them on the part.
Gasket, O-ring, and seals' mating surfaces must always be cleaned before installing the new part.
Gear - Always watch for damaged or worn teeth on gears.
- Burrs and rough spots should be removed with a honing stone or crocus cloth before putting gear in place. Lubricate mating surfaces before pressing gear on shafts.
Shafts - If a shaft does not come out easily, check that all nuts, bolts or retaining rings have been removed. See if other parts are in the way before using force.
- Shafts fitted to tapered splines should be very tight. If shafts are not tight, disassemble and check tapered splines. Discard parts that are worn. Be sure tapered splines are clean, dry, and free of burrs before putting them in place. Press mating parts together tightly.
- Clean off rust from all machined surfaces of new parts.
Part replacement - Always replace worn or damaged part with new parts.