Ball and Roller Bearings

Ball and Roller Bearings

When removing and installing bearings, ensure that the following practices are observed to ensure component serviceability.

• Remove all traces of lubricant from bearing under inspection by cleaning with a suitable degreasant; maintain absolute cleanliness throughout operations.
• Conduct a visual inspection for markings on rolling elements, raceways, outer surface of outer rings or inner surface of inner rings. Reject any bearings found to be marked, since marking in these areas indicates onset of wear.
• Hold inner race of bearing between finger and thumb of one hand and spin outer race to check that it rotates absolutely smoothly. Repeat, holding outer race and spinning inner race.
• Rotate outer ring gently with a reciprocating motion, while holding inner ring; feel for any check or obstruction to rotation. Reject bearing if action is not perfectly smooth.
• Lubricate bearing with generous amounts of lubricant appropriate to installation.
• Inspect shaft and bearing housing for discoloration or other markings which indicate movement between bearing and seatings.
• Ensure that shaft and housing are clean and free from burrs before fitting bearing.
• If one bearing of a pair shows an imperfection, it is advisable to replace both with new bearings; an exception could be if the faulty bearing had covered a low mileage, and it can be established that damage is confined to only one bearing.
• Never refit a ball or roller bearing without first ensuring that it is in a fully serviceable condition.
• When hub bearings are removed or displaced, new bearings must be fitted; do not attempt to refit the old hub bearings.

• When fitting a bearing to a shaft, only apply force to the inner ring of the bearing. When fitting a bearing into a housing, only apply force to the outer ring of the bearing.
• In the case of grease lubricated bearings (e.g. hub bearings) fill the space between bearing and outer seal with the recommended grade of grease before fitting seal.
• Always mark components of separable bearings (e.g. taper roller bearings) when dismantling, to ensure correct reassembly. Never fit new rollers in a used outer ring; always fit a complete new bearing assembly.