TOPIC 2. MAST ASSEMBLY

TM 10-3930-644-14&P

TOPIC 2. MAST ASSEMBLY

A. GENERAL

C. REMOVAL

The conversion of the hydraulic system fluid energy into

CAUTION

mechanical energy necessary in lift truck operation is

Fully retract or lower lift cylinders.

accomplished by the mast assembly. The high free lift

mast is constructed of two structural uprights. All high

1. Remove the carriage. (Refer to CARRIAGE

free lift masts utilize two (2) lift chains for safety and to

MAINTENANCE MANUAL.)

minimize the effect of off center loading. The chain

2. With the mast fully lowered, attach a sling From

anchors are individually adjustable to ensure equal

an overhead hoist to the mast lift eyes to secure

tension and a level fork carriage. The chains are

entire mast assembly during removal.

centrally located so as to offset any bending action on

the lift cylinder plunger(s).

CAUTION

Be certain overhead hoist is rated to

Should it become necessary to re-center the mast

safely

support

mast

assembly

uprights for smooth and even operation, the following

weight.

alignment Procedures are provided (adjustment method

varies with the model and load capacity of mast

3. Disconnect tilt cylinders from outer mast.

employed) : canted bearing type; wear plates and

4. Disconnect hydraulic hoses from lift cylinder: .

aligning shims; and roller bearings and aligning shims.

Each of these methods of adjustment is detailed in the

NOTE

following Paragraph F, ADJUSTMENTS.

Cap or plug hydraulic hoses and Inlet

and outlet parts on lift and tilt

B. MAINTENANCE LUBRICATION

cylinders to prevent contamination

by foreign particles.

1. 50 Hour Service

5. (PIVOT PIN TYPE) Remove lockwires,

After every 50 hours of operation, all inner and

capscrews, and lockwashers which retain pivot

outer web surfaces of the mast uprights should

pins to mast assembly. Raise overhead hoist

be lubricated. To perform this requirement, Fully

high enough to relieve pressure on the pins and

extend the mast; coat all inner and outer web

remove them. Use hoist to lay mast on suitable

surfaces of the mast uprights with a moderate

supports.

amount of high quality Grade 2 wheel bearing

grease or Grade 2 lithium base grease

NOTE

(characterized by the word "Moly").

Also

Adjustment of anted bearing type

lubricate all grease fittings.

mast

must

made

before

reassembly of mast.

(Refer to

2. 100 Hour Service

following

Paragraph

ADJUSTMENTS.)

Lubricate interlock spacer and screw, located on

inner section of cluster type or primary and

D. DISASSEMBLY-INSPECTION

secondary type cylinder mast. Use SAE 10 or

20 engine oil.

Refer to REPAIR MANUAL for proper DISASSEMBLY,

INSPECTION, REPAIR and REASSEMBLY procedures.

NOTE

E. INSTALLATION

The bearings used on the canted

bearing

type

mast

are

the

1. Use a properly rated hoist and maneuver the

prelubricated type and do not require

mast assembly into its relative mounting position

periodic lubrication. However, with

on front of lift truck.

this type of mast construction, the

2. Connect and properly secure the tilt cylinders.

camber or roller site of the bearing is

3. Reinstall hydraulic hoses.

designed to thrust against the face of

4. reinstall the carriage.

the mast uprights.

5. Lubricate mast uprights (Refer to preceding

Paragraph B, MAINTENANCE LUBRICATION.)

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