Taper Roller Bearings, Fault Diagnosis

Fault
Bent cage.
Cause
Improper handling or use of tool.
Remedy
Renew the bearing.

Fault
Galling.
Cause
Marks on roller ends due to overheating, lubricant failure or overloading.
Remedy
Renew the bearing. Check the seals and ensure that the bearing is properly lubricated.

Fault
Step wear.
Cause
Wear on the roller ends caused by fine abrasives.
Remedy
Clean all components and housings. Check the seals and bearings, and renew if leaking, rough or noisy.

Fault
Fretting.
Cause
Corrosion caused by small movement of components with no lubrication.
Remedy
Renew the bearing. Check the seals for leakage and ensure that there is adequate lubrication.

Fault
Misalignment.
Cause
Outer track misalignment usually due to a foreign body under the track.
Remedy
Clean all components and replace or renew the bearing and ensure that the new track is correctly seated.

Fault
Indentations.
Cause
Surfaces are depressed on the race and the track caused by hard particles of foreign material.
Remedy
Clean all components and housings. Check the seals and bearings, and renew if leaking, rough or noisy.

Fault
Flaking.
Cause
Flaking of the surface material due to fatigue.
Remedy
Renew the bearing and clean all related components.

Fault
Indentations.
Cause
Surface indentations in the track caused by rollers either vibrating or impact loading while the bearing is not rotating.
Remedy
Renew the bearing if rough or noisy.

Fault
Cage wear.
Cause
Wear around the outside diameter of the cage and roller pockets caused by poor lubrication and abrasive material.
Remedy
Renew the bearings and check the condition of the seals.

Fault
Roller wear.
Cause
Marks on track and rollers caused by fine abrasives.
Remedy
Clean all components and housings. Check the seals and bearings, and renew if leaking, rough or noisy.

Fault
Cracked race.
Cause
Race cracked due to incorrect fitting to shaft, tipping or poor seating.
Remedy
Renew the bearing and check the condition of the seals.

Fault
Discoloration.
Cause
Discoloration ranging from black to light brown caused by moisture or incorrect use of lubricants.
Remedy
Re-use bearings if stains can be removed by light polishing or if no evidence of overheating is apparent. Check the seals and other component part condition. Renew as necessary.

Fault
Discoloration.
Cause
Heat discoloration ranging from blue to faint yellow, resulting from overload or incorrect lubricant. As excessive heat can cause softening of tracks and rollers, check by drawing a fine file over a softened area. If faulty, the file will grab and cut metal. If still hard, the file will skid over the surface without removing any material.
Remedy
Renew the bearings and seals if any heat damage is evident.

Fault
Seizure.
Cause
Seizure caused by lack of lubrication, excessive loads or the ingress of foreign matter.
Remedy
Renew the bearings. Check the seals for wear and ensure that there is adequate lubrication.

Fault
Etching.
Cause
The bearing surfaces are grey or greyish black, with the rollers and track material being etched away. This is usually related to uneven spacing of the rollers.
Remedy
Renew the bearings. Check the seals for wear and ensure that there is adequate lubrication.

Fault
Rotating track and inner race material removal.
Cause
Removal of material due to slippage. This can be caused by poor fit, incorrect lubrication, overheating, overloading and poor assembly.
Remedy
Renew the bearings and clean all related parts. Check the fit and ensure the replacement bearings are the correct type. Renew the shaft or housing if damaged.