Put the protective cap back on the grease fitting.
With the drain plug still removed, put the unit back in
service. As the bearing warms up, excess grease will be expelled from the drain hole.
After the unit has been running for a few hours, the drain plug may be put back in
place. Special drain plugs with spring-loaded check valves are recommended because
they will protect against further buildup.
Generally, the time between flushing and repacking for greased
bearings should be divided by 2 for every 25F (14C) above 150F (65C) operating
temperature. Also, generally, the time between lubrications should not be allowed to
exceed 48 months, since lube component separation and oxidation can become
significant after this period of time, regardless of amount of use.
Another point worth noting is that grease is normally not
suitable for moving elements with speeds exceeding 12,000 inches per minute (5 mps).
Usually, oil lubricating systems are used for higher speeds. Lighter viscosity oils are
recommended for high speeds, and, within the same speed and temperature range, a
roller bearing will normally require one grade heavier viscosity than a ball bearing.
Keep lubricant containers tightly closed, except when in use,
to prevent contamination of the lubricant by the entrance of dust, grit, and abrasives.
Store lubricants in dust-free areas. Before using lubricant containers, wipe the spouts
and lips; before using grease guns, wipe the gun and fitting to ensure the absence of
A good rule of thumb is to change and flush oil completely at
the end of 600 hours of operation or 3 months, whichever occurs first. More specific
procedures for flushing and changing lubricants are outlined by most equipment
Every operator should be aware of the dangers of overfilling
with either grease or oil. Overfilling can result in high pressures and temperatures, and
ruined seals or other components. It has been observed that more antifriction bearings
are ruined by over greasing than by neglect.
A thermometer can tell a great deal about the condition of a
bearing. Ball bearings are generally in trouble above 180F (82C). Grease-packed
bearings typically run 10 to 50F (5 to 30C) above ambient temperature.