Ball and roller bearings

GENERAL INFORMATION

03-8

Ball and roller bearings

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

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Remove all traces of lubricant from the bearing 
under inspection by cleaning with a suitable 
degreasant; maintain absolute cleanliness 
throughout operations.

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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.

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Hold inner race of bearing between finger and 
thumb of one hand and  spin outer race to check 
that it revolves absolutely smoothly.  Repeat, 
holding outer race and spinning inner race.

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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.

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Lubricate bearing with generous amounts of 
lubricant appropriate to installation.

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Inspect shaft and bearing housing for 
discoloration or  other markings which indicate 
movement between bearing and seatings. 

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Ensure that shaft and housing are clean and 
free from burrs before fitting bearing.

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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.

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Never refit a ball or roller bearing without first 
ensuring that it is in a fully serviceable condition.

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When hub bearings are removed or displaced, 
NEW bearings must be fitted; do not attempt to 
refit the old hub bearings.

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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.

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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.

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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.