TM-9-2320-272-24-4

TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)

TECHNICAL MANUAL; UNIT, DIRECT SUPPORT, AND GENERAL SUPPORT MAINTENANCE MANUAL; VOLUME 4 OF 4

JUNE 1998

TM-9-2320-272-24-4 - Page 614 of 836

5-102. BOOM

TM 9-2320-272-24-4

WARNING

Drycleaning solvent is flammable and will not be used near open

flame. Use only in well-ventilated places. Failure to do this may

result in injury to personnel.

1.

Clean all parts of elevating cylinder with drycleaning solvent and dry with lint-free cloth.

2.

Inspect piston rod (9) for burrs, scoring, scratches, and stripped threads. If minor scratches and

burrs are present, remove with crocus cloth.

3.

If piston rod (9) is scored, scratched, or if stripped threads are evident, replace piston rod (9).

4.

Inspect piston (13) and cylinder body (1) for scoring. If piston (13) is scored, replace. If cylinder

body (1) is scored, replace elevating cylinder.

1.

Install two lubrication fittings (2) in cylinder body (1) and piston rod (9).

2.

Install sleeve (10) in piston rod (9).

3.

Install two half rings (3) on piston (13).

4.

Install piston rod bushing (6) in cylinder head (5) with bushing installer and handle.

5.

Install new O-ring (4), new packing (7), packing nut (8), and new wiper strip (11) on cylinder head (5).

CAUTION

Be careful not to damage wiper strip when passing over threads

on piston rod.

6.

Install cylinder head (5) on piston rod (9).

7.

Install new rod seal (12), piston (13), new seal (14), retainer (15), and washer (16) on piston rod (9).

8.

Install nut (18) on piston rod (9) and secure nut (18) with lockwire (17).

9.

Slide piston rod (9) into cylinder body (1) and install cylinder head (5) on cylinder body (1).

10.

Using spanner wrench, tighten cylinder head (5).

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