Basic Maintenance Skills

Bearing Maintenance

Keep things clean

• Do not unpack new bearings until you're sure you're going to mount them.
• Do not open seals unless you really really have to.
• Clean your skin and clothes before opening bearings.
• Sanitize the work area as much as possible. At a minimum, lay bearings and tools on clean newspaper.
• Cover parts with clean newspaper when not working.
• Flush bearing parts with solvent before reassembly
• Keep clean. Bearing failure is almost always caused by contamination.

Be careful when pulling bearings

• Use proper equipment; something that only contacts the inner bearing race. Don't press against the balls/cages.
• Do not apply uneven pressure to bearing. That will twist it in its support. Push/pull tool must be cut square.
• Do not hammer on housing or shaft.

Bearing/shaft inspection

• Bearings should be round. Replace if any surface is pitted, nicked or flattened.
• Bearings should rotate freely. Replace if rotation catches or makes noise.
• When in doubt, replace. If in a critical position, replace at each overhaul.
• Surfaces that contact the bearing should be smooth. Check that shaft and shoulders are square with no burrs.

Inspect new bearings

• Compare bearing dimensions to requirements. EX: don't use a 5mm wide bearing when a 10mm width is called for.
• Check bearing construction against application. EX: don't use angular contact bearings to take a thrust load.
• Ensure bearing shields are as specified. EX: don't use water resistant shielding when water proof is necessary.

Carefully install bearings

• Spread some oil lightly over the inner surface of the bearing.
• Check bearing markings for proper orientation upon installation.
• Press firmly against shaft shoulder.
• Install accessories like snap rings properly, flat side against bearing.
• Lubricate according to manual