Lull 944E-42, Service Manual

Page: 147 / 844

5.3 Model 644E-42/944E-42 Rev. 6/04
Axles, Drive Shafts, Wheels, Tires and Brakes
5.2 GENERAL INFORMATION
IMPORTANT: To help ensure optimum performance, the
drive shaft assemblies are specially balanced as a unit at
the factory. When servicing any flange yoke, slip yoke or
drive shaft tube, order a complete assembly if
components are bent or damaged. Refer to the
appropriate Parts Manual for ordering information.
Before performing any inspection, maintenance or
service operation, thoroughly clean the unit. The axles
and drive shafts should be checked and repaired only by
experienced service technicians who are aware of all
safety instructions and particular component features.
Use suitable products to thoroughly clean all
disassembled mechanical parts to help prevent personal
injury to the worker and damage to the parts. Carefully
inspect the integrity of all moving parts (bearings, yokes,
tubes, gears, shafts, etc.) and fasteners (nuts, bolts,
washers, etc.) as they are subject to major stress and
wear. Always replace elastic-lined nuts and any
damaged, worn, cracked, seized, or otherwise improper
parts that could affect the safe and proper functioning of
the vehicle, axles and drive shafts.
5.3 AXLE ASSEMBLIES
5.3.1 Axle Assembly Description
The front (parking brake-equipped) and rear (no parking
brake) ZF axles are designed for heavy-duty, off-road
industrial use. Each axle consists of a beam-type axle
case, housing the differential center section, inboard wet-
disc brakes, a pair of trumpet-like shaft housings and
stub-axle/wheel-hub units at each end. O-rings and oil
seals retain fluid within the axle. The axles have a semi-
floating mounting configuration. Each axle center is
secured to the vehicle frame with semi-rotating front and
rear supports, and at one side with a cylinder, anchor and
pins.
The frame sway cylinder is mounted on the right side of
the front axle. Steering cylinders and ball joints are
mounted inboard on each axle.
5.3.2 Axle Assembly Operation
Power from the engine is transmitted to the transmission
by way of a driveshaft. The transmission distributes
power through the output drive shafts to the front and rear
axle differentials. The axles work through gearing to turn
the wheel and tire assemblies, and to ultimately cause
the vehicle to move.
The front differential is equipped with limited-slip, self-
locking gears, supported by bearings. The design of the
differential permits adjustment to the bevel gear set.
Internal axle service and adjustment procedures are not
the scope of this publication, and are thoroughly covered
in the appropriate ZF axle manual. The beveled ring gear
is adjusted by means of ring nuts located opposite each
other. The position of the pinion, supported by two
bearings, is adjusted through the addition or subtraction
of adjusting shims.
The wheel hubs containing the planetary reduction gears
are supported by two tapered roller bearings. The oil-bath
(wet) disc-type brakes are located in the center housing
and are operated by an annular piston. The parking brake
is located in the center section of the front axle. The brake
is spring-applied, hydraulically released (SAHR). The
parking brake uses the same discs as the service brakes.
A double-rod hydraulic steering cylinder is mounted on
the differential support. Directional steering input is
transmitted to the axles by means of articulated track
rods that allow toe-in adjustments.
The axles are supported with two specially designed
support trunnions (one at the front and one at the rear of
each axle), attached to the axle center and chassis. The
trunnions allow the axle to pivot freely, the front axle
movement is limited by a hydraulic cylinder attached to
the bridge casting bearing lug.
Note: Detailed axle service instructions (covering axle,
brakes and wheel end safety, repair, disassembly,
reassembly, adjustment and troubleshooting information)
are provided in the ZF Axle Repair Manual, (944E Front)
Model MS-T 3060, JLG P/N 8990430 (ZF P/N 5871 560
002) and (944E Rear & 644E Front and Rear) Model
MS-T 3045, JLG P/N 8990419 (ZF P/N 5871 550 002).
One wheel type with nominal dimensions of 9'' x 24'' is
used on the Model 644E. The wheels are a one-piece
design with eight one-inch diameter holes equally spaced
on a 13.188" (275mm) diameter bolt circle.
A 12-ply (or better), directional-tread tire, 13.00 x 24"
size, can be used on the Model 644E. There is a 13.00 x
24" Foam fill option as well as 13.00 x 24" Radial and
13.00 x 24" Rock Tire.
One wheel type with nominal dimensions of 13" x 25" is
used on the Model 944E. The wheels are a one-piece
design with ten one-inch diameter holes equally spaced
on a 13.976" (355mm) diameter bolt circle.
A 12-ply (or better), directional-tread tire, 15.5 x 25" size,
can be used on the Model 944E. There is a 15.5 x 25"
Foam fill option as well as 15.5 x 25" Radial and
15.5 x 25" Rock Tire.
WARNING:
DO NOT service the vehicle
without following all safety precautions as
outlined in the “Safety Practices” section of this
manual. Failure to follow the safety practices
may result in death or serious injury.