SYMPTOM
CAUSE
SOLUTION
 Flaking

A.

On rolling elements 1. Excessive loading 1. Inspect machine design and bearing selection.
2. Excessive preloading 2. Careful installation
3. Overloading due to expansion 3. Analyze machine design and bearing application
B. Localized on raceway Presence of dirt, rust, or scratches Replacement, and consider use of a better protected bearing
C. Circumferential on raceway Presence of dirt, rust, or scratches Replacement, and consider use of a better protected bearing
D. Areas facing each other on the raceway 1. Misalignment of shaft or bearing housings Correct misalignment and install replacement with care
2. Improper installation
3. Wear
E. Off-center, i.e., circumferential on one side Excessive thrust load Correct misalignment or improper installation; select more suitable bearing
F. Diagonal on the raceway 1. Deflection of shaft Correct misalignment or improper installation; select more suitable bearing
2. Misalignment of inner and outer races
G. Areas spaced at pitch intervals of the rolling elements 1. Vibration without rotation Suppress vibration; better protection of bearings
2. Rust
 Seizing
A. Cracking 1. Overloading Misapplication; Preload properly; check method of lubrication and selection of lubricant
  2. Improper lubrication, e.g.,
  3. Improper lubricant
B. Visible damage Overloading Select more suitable bearing
 Cracking
A. Cracking 1. Flaking due impact while in operation or during installation 1. Careful handling and installation
2. Excessive clearance 2. Inspect mounting and preloading
3. Excessive interference or out of roundness 3.. Check for proper fit and concentricity
B. Splitting large shaft radius at bearing mounting shoulder Inspect accuracy of shaft and bearing housing construction
 Rust
A. Throughout bearing 1. Improper storage Consideration of storage, maintenance and corrosion inhibition
2 Left unprotected
3. Poor cleaning
4. Inadequate rust inhibition
B. Localized 1. Improper packaging Improved storage and maintenance practices
2. Sweating hands
C. Corrosion on mounting surfaces, i.e., inner ring bore or outer ring outside diameter 1. Loose mounting Reconsider construction of shafts and bearing housings; reconsider moisture protection
2. Inadequate protection
 Wear
A. Rapid wear of rolling elements or races 1. Presence of dirt in lubricant Inspect lubricants and lubrication
2. Rusting
B. Retainer wear Improper lubrication, e.g., lack of Inspect lubricants and lubrication
 Electrical erosion
Crater-like pitting (fluting) Electrical sparking Ground stray currents; insulate bearing
 Roughening
A. Roughness Dirt pressed between rolling elements and raceways Improve maintenance practices
B. Sparkling surfaces Improve maintenance practices
C. Striking during handling Careless handling Improve maintenance practices
D. Damage during installation Careless installation Improve maintenance practices
 Smearing
Scratched surfaces of raceways or rolling elements 1. Improper lubrication Inspect lubricant and method of lubrication
2. Skewing of rolling elements
3. Improper lubricant
 Creep
A. Wear of race mounting surfaces 1. Excessive clearance in mounting Inspect seating and accuracy of construction of shaft and bearing housings; reevaluate design
2. Looseness of bearing retainer
B. Slippage, discoloration Abrasion Inspect seating and accuracy of construction of shaft and bearing housings; reevaluate design