SECTION V. UNIT MAINTENANCE PROCEDURES
4-9. GENERAL MAINTENANCE PROCEDURES. This section describes general procedures that apply to
all maintenance tasks detailed in this manual. To avoid repetition, these general procedures will not be
repeated elsewhere in the manual.
4-9.1. General Removal and Disassembly Instructions
Troubleshooting. Before removing any item, refer to the troubleshooting table. This ensures that faults
are isolated to a particular component.
Cleanliness. Work areas must be kept clean. This avoids contamination of internal parts. This is
especially true for areas where controls, valves, cylinders, or other hydraulic or air system parts are
De-energize and De-pressurize. Before removing any part of electrical, hydraulic, pneumatic, or foam
systems ensure the system is not energized or pressurized (e.g. disconnect batteries or relieve all
pressure from air system by opening drain valves). Ensure that all controls are in the OFF position before
starting any removal procedure.
Preparation. Study the task description before disassembling or removing any item. This reduces job time
as all tools and equipment will be available and procedures will have been noted.
Work Space. Ensure there is sufficient clearance to remove or disassemble a particular part.
Disassemble adjacent parts as necessary to provide reasonable working clearance.
Lifting. Use a hoist, jack, or other aid when lifting heavy parts. Lifting devices should be positioned and
attached to the part to remove all strain from mounting hardware before part is removed. Never work
under a part which is supported only by a lifting device. Always support that part on maintenance trestles
or other supports before starting work.
Lifting Truck. In certain cases it will be necessary to raise the truck so that all tires clear the ground. The
following procedure describes a safe method of lifting the truck.
Drain water tank to reduce truck weight.
Park truck on level, hard surface. Position gear selector to N (neutral) and apply parking brakes.
Chock wheels of opposite axle.
Place 1O ton hydraulic jack beneath differential. Raise the jack until tires clear the ground.
Place maintenance trestles beneath axle, one on each side of differential. If truck is to be
supported by frame, and tires still need to clear the ground, raise the truck high enough to
compensate for leaf spring sag.
Carefully lower truck onto maintenance trestles. Be sure maintenance trestles are adjusted to the
same height and are of sufficient capacity to carry truck weight.
Repeat steps 4 through 6 to raise other axle.