Cummins/Onan — Generator Disassembly / Reassembly
Repair & overhaul · Generator assembly
From a Cummins/Onan service manual — check it applies to your exact model before use.
Applies to: Cummins/Onan DFE
Before you start
- To prevent personal injury, use adequate lifting devices to support heavy components. Keep hands and feet clear while lifting.
- Drive disc damage can be caused by allowing the rotor assembly to hang on flywheel.
Procedure
- Reassembly is the reverse of disassembly procedure.
- Locate the generator assembly into position near the engine flywheel housing.
- Align engine adaptor endbracket holes with flywheel housing holes and install capscrews and lock washers; tighten to 65-70 ft-lbs (88-95 N-m).
- Align rotor drive disc holes with engine flywheel holes; install capscrews and flat washers.
- Secure rotor assembly to flywheel; tighten to 75-85 ft-lbs (102-115 N-m).
- Secure generator foot brackets to vibration isolators; apply Loctite 271 to M20 screw and tighten to 270-330 ft-lbs (365-447 N-m).
- Install endbracket to stator frame using capscrews and lock washers.
- Insert and start threads of bearing cartridge fasteners into cartridge housing.
- Lift endbracket slightly and remove wooden shims holding rotor on center with stator.
- Tighten endbracket fasteners securely.
- Tighten bearing cartridge fasteners to 4.5 ft-lbs (6 N-m).
- Install PMG assembly if removed.
- Use lifting device to mount control housing to skid; replace capscrews and lock washers and tighten to 18 ft-lbs (24 N-m).
- Connect all control wires and generator leads using the proper generator set AC and DC wiring diagram.
- Connect the negative (-) battery cable, connect battery charger, and test the generator set.
Tools required
- Adequate lifting device Amazon
- Hoist and sling Amazon
- Forklift Amazon
- Wood pry bar Amazon
- Wooden shims Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Engine adaptor endbracket: 65-70 ft-lbs (88-95 N-m)
- Rotor to flywheel: 75-85 ft-lbs (102-115 N-m)
- Foot brackets M20: 270-330 ft-lbs (365-447 N-m)
- Exciter stator: 4.5 ft-lbs (6 N-m)
- Bearing cartridge: 4.5 ft-lbs (6 N-m)
- Control housing: 18 ft-lbs (24 N-m)
Full service-parts list: Cummins/Onan DFE →
Source: Cummins/Onan service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.