Cummins/Onan — AC Generator Removal and Disassembly

For these Cummins/Onan models: GS-107-AC, J120-8/967F, J120-S/967F.

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Procedure

1. Release the end cover by removing the securing hardware to expose the bearing bracket assembly
2. The exciter field frame may then be released from the bearing bracket assembly or the complete bearing bracket assembly may be removed and disassembled at a more convenient working area
3. Locate and identify inter-connecting wires before disconnecting
4. Place blocking under the stator housing and remove the brushes to prevent damage when assembly is drawn off the rotating parts
5. Release the bearing bracket assembly by removing the nuts and washers securing it to the stator housing at the long studs
6. The exciter armature is now exposed and can be released by removing the nut and washer securing it to the shaft extension
7. Release the generator leads at the connection board, the fuel line and electrical connections to the engine and the support structure for the control box and fuel tank from the generator housing
8. Disengage the stator housing from the adapter frame, placing blocking under it to prevent dropping and maintain alignment
9. Remove the stator studs from the adapter frame
10. Place blocking under the rotor assembly
11. Release the rotor by removing the long nut and washer securing it to the shaft extension
12. Disengage the rotor from the crankshaft extension and remove it
13. Release the adapter frame from the engine by removing the securing screws and lock-washers

Source: manual:HOL-GAR GS-107-AC.pdf. Figures and steps are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.