Investigate noise, heat, vibration and damage. Build an evidence trail before choosing a replacement.
Turn an observation into a focused inspection record. This tool suggests checks, not a diagnosis, a replacement or permission to keep operating.
Choose the main observation to build an inspection plan.
Lubrication, contamination, contact damage or mounting conditions may be involved. The sound can also come from nearby components.
Next check: Describe the sound and record its timing beside speed and load. Compare the same location under comparable conditions.
Open the noise observation guide →Lubrication quantity, reduced clearance, mounting or seal friction are possibilities; a temperature reading alone cannot distinguish them.
Next check: Keep the measurement location and method consistent. Check the machine's own alarm limits and the event before the rise.
Open the overheating investigation →A vibration change needs investigation, but does not by itself identify bearing damage.
Next check: Retain the original measurements and acquisition setup. Compare with the same machine position at a comparable operating point.
Open the vibration evidence worksheet →Foreign material, contact-surface damage or mounting conditions can affect movement.
Next check: Use the equipment's isolation procedure before physical inspection. Preserve the as-found condition rather than forcing the bearing to turn.
Open the inspection procedure →Ingress or wear may be involved. Appearance alone does not establish the material's identity or the cause.
Next check: Record the lubricant and sealing history. Keep an appropriately identified sample before cleaning removes evidence.
Open the contamination checks →Do not remove guards or touch moving parts to collect evidence. Follow the machine's controlled shutdown and energy-isolation instructions before hands-on inspection. This planner provides no safe running time, alarm threshold or reuse approval.
Technical basis: NSK operation inspection, bearing inspection and damage guidance; JTEKT test-run and failure-analysis guidance. Original BearingScope decision workflow. Reviewed 4 October 2026; source snapshots retained in the private audit.
Filter by the damaged interface and visible feature. These original diagrams explain patterns; they do not identify a failure from a photograph or replace inspection.
10 pattern references · not a diagnosis
Pieces of contact-surface material have detached, leaving an uneven, coarse area.
Compare the damage distribution with load, alignment, lubrication, contamination and clearance history. Earlier dents or corrosion may have contributed.
A spall describes damage, not its unique origin. It does not prove a defective material or that calculated fatigue life was reached.
Sliding and disruption of the lubricating film can produce local adhesion and a rough, smeared contact surface.
Review speed and load together, starts and stops, lubricant suitability and water ingress. Preserve the original surface and lubricant evidence.
Do not infer an exact temperature from a mark or prescribe more preload. The acceptable load, clearance and lubrication depend on the bearing arrangement.
Inspect pocket bridges, side faces and guiding surfaces for fracture, distortion or wear.
Retain fragments and their positions. Check handling, mounting, load, vibration, speed changes, lubrication and temperature history.
A broken cage need not be the initiating failure. Changing cage material or fitting an arbitrary cage from another bearing is not a verified remedy.
Debris trapped in rolling contact can indent a surface. Shock or excessive loading can also leave dents; mounting impacts may produce marks at element spacing.
Record debris, handling and transport events, assembly-force paths and the spacing of marks.
Repeated marks alone cannot separate indentation from false brinelling. Compare surface condition and loading history before naming the mechanism.
Small repeated movement can wear hollows at rolling-element contact positions, including during standstill vibration or small-angle oscillation.
Separate running history from transport, storage and standby vibration. Record the surface texture and lubrication condition.
This is not simply another name for impact indentation. Similar spacing is possible in different mechanisms; there is no universal transport or rotation schedule.
Relative slip between a ring and its shaft or housing seat can leave shiny, worn or scored fitting surfaces.
Measure the ring seat and mating component against the drawing. Review fit and sleeve-tightening records for the actual arrangement.
Internal bearing clearance is not the same as a loose shaft or housing fit. Adhesive or increased interference is not an automatic repair.
Discharge through a contact can produce local melting and craters; developed damage may appear as groove-like fluting.
Preserve magnified surface evidence. Qualified personnel should investigate the electrical system and possible current path with appropriate methods.
A striped track or a vibration spectrum alone does not establish electrical damage. Compare mechanical wear, false brinelling and corrosion evidence.
Corrosion can affect rings and rolling elements, sometimes across a surface and sometimes at repeated contact positions.
Trace water or corrosive exposure, condensation, lubricant condition, handling and storage protection.
Colour and spacing are not conclusive. Removing staining does not restore a pitted rolling contact or establish that reuse is acceptable.
Repeated small sliding movements can cause wear at fits or rolling contacts; associated debris may appear reddish-brown or dark.
Document the exact damaged interface and small-motion history. Check the relevant fit and lubrication condition.
Fretting is not identical to moisture corrosion or sustained ring creep. False brinelling is a contact-position wear pattern within this small-motion context.
Sliding can progressively deteriorate raceways, rolling elements, ribs or cage contact surfaces. Debris and lubrication problems may contribute.
Check the affected surfaces together with sealing, cleanliness and lubricant evidence. Record changes before cleaning.
A bright surface alone does not quantify wear. Acceptable dimensions and reuse criteria require the exact component and its service specification.
No pattern in this reference matches both filters. This is not proof that damage is absent. Clear a filter or use the full inspection procedure.
Technical basis: NSK Bearing Doctor, individual damage-type references. Original BearingScope illustrations and investigation prompts, reviewed 4 October 2026. Colour, shape and depth are illustrative; source snapshots are retained in the internal audit.
Find a guide, table or tool by your question, task and equipment. Product records stay in the model catalogue.
The cage separates and guides rolling elements; it is not a replacement for the raceways' load-carrying function. A damaged cage can be an outcome of another problem, so retain…
Diagnose a problem ↗Flaking or spalling is loss of material from a rolling contact surface. Replacing the bearing removes the damaged component but does not establish why it failed. Record where…
Diagnose a problem ↗A sound description narrows an investigation; it does not identify a failed part. Compare the noise with speed, load, temperature and vibration before choosing a replacement.…
Diagnose a problem ↗Start with the temperature trend and operating conditions, not a universal alarm temperature. Too much lubricant, too little lubricant, unsuitable lubricant, excessive load and…
Diagnose a problem ↗Ring creep is relative movement between a bearing ring and its seat. It is different from rolling motion inside the bearing. Inspect both the ring seat and the shaft or…
Diagnose a problem ↗Corrosion is a surface condition to investigate, not an instruction to clean and reuse. Record where moisture or chemicals could enter and whether damage reaches rolling…
Diagnose a problem ↗A seized or heavily smeared bearing calls for an investigation of lubrication, loading and assembly conditions, not an attempt to free it and continue running. Retain evidence…
Diagnose a problem ↗Trend vibration at comparable speed and load, then investigate spectral features with known bearing geometry. BPFO, BPFI, BSF and FTF describe idealised kinematics; slip and…
Diagnose a problem ↗Wear, scratches and debris need to be considered together with lubricant and sealing condition. A worn bearing may have increased movement, but a measured clearance must be…
Diagnose a problem ↗Electrical discharge across the lubricating film can damage rolling contacts. Fine craters or washboard-like fluting warrant an electrical investigation, particularly in…
Diagnose a problem ↗Similar-looking marks can come from different mechanisms. False brinelling is associated with small repetitive movements at contacts; permanent indentation involves local…
Diagnose a problem ↗A hum or rumble does not uniquely identify a wheel bearing; tyres, brakes and driveline components can produce similar symptoms. Wheel-bearing identification and inspection…
Diagnose a problem ↗Remove a filter or try a shorter term. A missing guide does not mean a product is unavailable.