Disassemble and Service. Unless a complete overhaul is required, disassemble main rotor assembly only to the
extent required to dean, repair, or replace a dirty, damaged or defective component. Do not disassemble rotor if
coil rewinding is required. Rewinding is performed by depot or the manufacturer. Remove, inspect and dean; or
repair main rotor assembly components and auxiliaries in accordance with the procedures below. Install
components in accordance with step c, below. Disassemble main rotor assembly as follows:
Dry deaning solvent. PD-680, Type III, or equivalent, Is flammable and moderately
toxic to the skin, eyes, and respiratory tract. Assure adequate ventilation. Skin,
eye, and respiratory protection Is required to avoid injury to personnel.
Compressed air used for cleaning or drying can create airborne particles that may
enter the eyes. Pressure shall not exceed 30 psi (207 kPa). Wearing of goggles Is
required to avoid Injury to personnel.
Coupling drive discs and spacer (22 and 24, Figure 5-1).
(a) Remove. Remove coupling drive discs (22) and spacer (24) in accordance with step a, above.
(b) Inspect and dean.
1 Inspect coupling drive discs (22) and spacers (24) for distorted or bent edges and other damage.
Check for worn mounting holes. Inspect drive disc hexagonal head screws (20) for damaged threads.
2 Clean coupling drive discs (22) and spacers (24) with solvent PD-680, Type 111, or equivalent. Dry
thoroughly with compressed air.
(c) Repair. Repair by replacement of damaged components. Replace all defective discs as necessary.
Replace spacers, if damaged. Replace screws if damaged.
(d) Install. Install drive discs in accordance with paragraph 5-9.
(a) Remove. Remove the machining adapter (25, Figure 5-1) in accordance with step a, above.
(b) Inspect and Clean.
1 Inspect the machining adapter for cracks, burred or rough mating and other damaged surfaces.
Inspect the hexagon head screws (26) for stripped threads. Replace if defective.
2 Clean the machining adapter (25), hexagon head screws (26), and screen assembly (3) in solvent
PD-680, Type III, or equivalent, to remove all dust, dirt, and grease. Dry the parts thoroughly with
(c) Repair. Repair by replacement. Replace the machining adapter (25) if damaged. Replace the
hexagon head screws (26) as needed.
(d) Install. Install machining adapter (25) in accordance with paragraph 5-9, step b.
Ball Bearing and Bearing Cap (39 and 18, Figure 5-1).
(a) Inspect and Clean. inspect the ball bearing (39) for damage or wear while bearing (39) is installed on
the rotor assembly (15, Figure 5-1). Inspect bearing cap for worn threads in the screw mounting holes.
(b) Repair. Repair by replacement. Replace bearing cap if threads are wom.
If the ball bearing is removed for any reason, always install a new ball bearing.
1 Remove retainer ring (38), then remove the ball bearing (39) with a general purpose puller with 20
ton (9072 kg) capacity.
2 Slide off bearing cap (18) from the main rotor shaft. Remove and discard oil seal (7) if bearing cap
is to be removed.