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 616 of 836

5-103. BOOM

TM 9-2320-272-24-4

THIS TASK COVERS:

a. Removal

b. Installation

INITIAL SETUP:

APPLICABLE MODELS

M936/A1/A2

REFERENCES (TM)

LO 9-2320-272-12

TM 9-2320-272-10

TM 9-2320-272-24P

SPECIAL TOOLS

Spanner wrench (Appendix E, Item 167)

TOOLS

General mechanic’s tool kit (Appendix E, Item 1)

Boom lifting device

MATERIALS/PARTS

Packing (Appendix D, Item 510)

GAA grease (Appendix C, Item 28)

EQUIPMENT CONDITION

Parking brake set (TM 9-2320-272-10).

Boom lowered (TM 9-2320-272-10).

GENERAL SAFETY INSTRUCTIONS

All personnel must stand clear during lifting

operations.

WARNING

All personnel must stand clear during lifting operations. A

snapped cable, or shifting or swinging load ,may cause injury to

personnel.

1.

Place wrecker boom (2) cylinder control lever (7) in UP position.

2.

Raise wrecker boom (2) with lifting device and install shipper braces (TM 9-2320-272-10).

3.

Place boom cylinder control lever (7) in LOWER position to release pressure from elevating cylinder (6).

4.

Using spanner wrench, loosen packing nut (3) from cylinder head (5).

5.

Slide nut (3) up on piston rod (1) to expose packing (4).

CAUTION

Use care not to scratch piston rod surface when removing packing.

6.

Slide packing (4) up piston rod (1) and remove. Discard packing (4).

1.

Coat packing (4) with GAA grease and position around piston rod (1).

2.

Install packing (4) into cylinder head (5) and slide nut (3) onto cylinder head (5).

3.

Using spanner wrench, tighten nut (3).

4.

Remove lifting device from wrecker boom (2).

5-610