Wheel-end maintenance (hub bearings, seals, lubrication) — SKF TFO guide + STEMCO/TMC RP 631

• Source / publisher: SKF (Trouble-Free Operation programme); STEMCO; TMC Recommended Practice 631 (STEMCO-hosted)
• Type: guide + standard (maintenance manual + inspection schedule + industry RP)
• Topics: wheel-end inspection intervals (pretrip leak check, annual/100k-mile detailed, pre-adjusted hub service), bearing removal/installation (the #1 cause of premature failure is improper R&I — the core lesson), end-play adjustment procedure, seal condition checks, lubricant type/level (oil vs semi-fluid grease, 3-and-9-o'clock fill), hubcap/sight-glass checks, ProTorq keeper logic, TMC RP 631 lubrication inspection levels
• Vehicle scope: truck + trailer
• Region: global (US-published)
• Language: en
• Link: cdn.skfmediahub.skf.com | License/access: public
• Notes:
  • SKF TFO guide is the definitive wheel-end teaching doc — it teaches failure causality (R&I damage → seal leaks → bearing death), not just intervals.
  • STEMCO Tech Tip #21 (Oct-2020) gives the interval ladder: daily pretrip visual → annual/100k detailed → RP631B semi-fluid-grease Level-III: stemco.com
  • TMC RP-631C itself (free via STEMCO): stemco.com — genuine industry-standard practice text.
  • Cross-ref: wheel/tyre servicing safety lives in OSHA rim-wheel safety — this file covers the hub internals side.