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Do It Yourself - Outdoor Power Equipment Repair & Maintenance

Electric PTO Clutches Handy Hints

Electric PTO Clutches Handy Hints Posted in Lawn Mowers

The two most important requirements for a successful clutch application or installation:

  1. Anti-rotation device must allow both axial and radial free-play. Failure to allow this free-play will result in field bearing failure. The greater the restriction the faster the bearing will fail.
  2. Mounting bolt torque to be minimum of: 3/8"-24 UNF use Grade 8 bolt torqued to 40/45 lb.-ft. (Grade 5 bolt is unacceptable) 7/16"-20 UNF Grade 5 or 8 bolt torqued to 50-55 lb.-ft. (Grade 5 or 8 bolt is acceptable) M 10 X 1.50 Class 10.9 torqued to 55-60 N-m.

Install mounting bolt and retaining washer and torque to spec for the clutch to work properly.

Use Grade 5 or Grade 8 bolt only. Minimum torque:

  • 7/16 in. UNF bolt is 50ftlb/67 Nm
  • 3/8 in. UNF bolt is 31ftlb/42 Nm
  • M10x1.5 bolt is 35ftlb/48 Nm

Most applications that mount directly to the crankshaft use a "CCW" for standard mount (pulley away for engine). A "CCW" rotation is normally used for reverse mounting (pulley towards engine). If a clutch is mounted incorrectly then the springs will be run in compression and it will cause the springs to fail.

Warning - Anything less than required mounting torque could result in clutch failure, thus voiding warranty.

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