Kaydon bearing remanufacturing program

At a glance: six steps to save slewing ring bearings

More than 96% of slewing ring failure could be avoided by following simple maintenance tips.

Grease regularly.
Apply a liberal shot of extreme-pressure grease to the fittings around the bearing's circumference at intervals recommended in the operator's manual.

Purge with grease.
Pump grease into the bearing until you see old grease squeeze past the seal. Purged grease can help carry any contaminants out of the bearing.

Inspect the grease.
Rub some of the purged grease between your thumb and forefinger. If you see or feel grit or metal chips in it, there may be a bearing problem.

Honor load charts.
Even slight overloads can dimple the bearing race. One 1/1000 of an inch depression will worsen with subsequent loads and cause eventual failure.

Avoid repetitive, heavy loads.
Lifting with the boom and undercarriage in the same position, such as repetitive curbside digging with an excavator, can put a dimple in the bearing race close to the uneven load. If possible, change the angle of approach from job to job.

Predict failure and repair the bearing.
If the turning torque of the bearing increases substantially, or if you notice a clicking or grinding noise when rotating the structure, grease the unit and have some of the purged lubricant analyzed for wear metals.

Play or clearance in the bearing can indicate a problem and will show up as a lack of 'stiffness' in the extended boom. Free play magnified over the length of the boom allows it to rock back and forth under load. Check bearing clearance with a dial indicator that measures how much the structure tilts when the boom is loaded.

Even when a detailed maintenance program is followed, bearings will eventually become worn. Well-maintained bearings can usually be repaired at less than half the cost of buying a replacement, if it is repaired before it fails.