Steps Prior Installing Gear Clutch In The M242

Do not clean annular ball bearings in solvent or allow solvent to run into bearings. Solvent will remain in bearing and dissolve lubricant, resulting in excessive wear or damage to bearing.

CLEANING - Continued

CLEAN CLUTCH ASSEMBLY PARTS.

a. Using brush and dry cleaning solvent, clean spur clutch gearshaft (1) and shouldered clutch shaft (2).

b. Wipe annular ball bearing (3) with clean, dry wiping rag.

INSPECTION

1. INSPECT CLUTCH ASSEMBLY PARTS.

a. Visually inspect spur clutch gearshaft (1) and shouldered clutch shaft (2) for cracks and broken shaft splines and gear teeth. If any of these conditions are found, replace defective part.

b. Visually inspect torsion spiral springs (3) and clutch rollers (4) for cracks, bends, and galls. If any of these conditions are found, replace defective part. Replace torsion spiral springs (3) as a set, if damaged.

1005 454 0396
DOUBLE SPRING CLUTCH ASSEMBLY

LUBRICATION

LUBRICATE CLUTCH ASSEMBLY PARTS.

Using acid brush, apply a light coat of grease to clutch assembly components (1), annular ball bearing (2), and inner and outer surface of each torsion spiral spring (3).

Torsion Spring Firearms

ASSEMBLY

1. ASSEMBLE CLUTCH ASSEMBLY.

Insert shouldered clutch shaft (1) in spur clutch gearshaft (2).

ASSEMBLY - Continued

2. INSTALL CLUTCH ROLLERS AND TORSION SPIRAL SPRINGS ON DOUBLE SPRING CLUTCH ASSEMBLY.

a. Insert inner torsion spiral spring (3) into outer torsion spiral spring (4). Make certain ends of springs are flush with each other.

Torsion Spring Pistols

b. Place three clutch rollers (5) into slots (6) in spur gearshaft (2).

c. Position assembled inner and outer torsion spiral springs (3) and (4) over clutch rollers (5). Slide torsion spiral springs (3) and (4) along clutch rollers (5) until seated firmly against spur clutch gearshaft (2).

TESTING

TEST CLUTCH ASSEMBLY SLIPPAGE TORQUE.

a. Place the base (1) of receiver clutch slippage torque test holder tool in vise.

b. Insert splined gearshaft (2) into tool.

c. Using torque wrench and top piece (3) of torque test tool, torque clutch gear (4) in clockwise direction. Record the highest torque value (slippage torque) at which the torsion spiral springs (5) expand and allow the clutch gear (4) to rotate (slip).

d. Double Spring Clutch Only: Replace torsion spiral springs (5) if slippage torque is not 50 ft-lb ± 12 ft-lb (67.8 N-m ± 16.3 N-m).

e. Triple Spring Clutch Only: Replace torsion spiral springs (5) if slippage torque is not 71 ft-lb ± 21 ft-lb (96.5 N-m ± 27.8 N-m).

Direct Current Motor Removal M242

NOTE

For clutch assembly INSTALLATION procedures, return to WP 0067 00.

END OF WORK PACKAGE

UNIT

M242 25-MM AUTOMATIC GUN (NSN 1005-01-086-1400) M242 25-MM ENHANCED AUTOMATIC GUN (NSN 1005-01-454-0396)

CHAIN GUIDES AND MECHANICAL INTERLOCK DISASSEMBLY/ASSEMBLY DISASSEMBLY, CLEANING, INSPECTION, LUBRICATION, ASSEMBLY

INITIAL SETUP:

Tools and Special Tools

Artillery and turret mechanic's tool kit

(item 41, WP 0085 00) Goggles (item 19, WP 0085 00) Rubber gloves (item 18, WP 0085 00) Turret mechanic's supplemental tool kit (item 44, WP 0085 00)

Materials/Parts

Acid brush (item 4, WP 0116 00)

Adhesive (item 1, WP 0116 00)

Cotter pin (MS24665-132)

Dry cleaning solvent (item 27, WP 0116 00)

Grease (item 11, WP 0116 00)

Lockwire (item 34, WP 0116 00)

Sealing compound primer (item 20,

WP 0116 00) Spring pin (12524618-1) Wiping rags (item 21, WP 0116 00)

References

WP 0008 00

Equipment Conditions

WP 0026 00 Automatic gun feeder removed WP 0049 00 Recoil mechanism removed if required (see note prior to step 1 in this work package)

WP 0050 00 Barrel support assembly removed, if required (see note prior to step 1 in this work package) WP 0051 00 Breech assembly removed, if required (see note prior to step 1 in this work package)

WP 0053 00 Bolt and track assembly removed WP 0060 00 Straight drive shaft removed WP 0061 00 Direct current motor removed WP 0063 00 Cover assembly and sear retractor assembly removed WP 0064 00 Sear catch assembly removed WP 0065 00 Sear removed

Special Environmental Conditions

Well-ventilated area required when using dry cleaning solvent.

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