Operation & Maintenance Manual
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LG968 /969Wheel Loader
103
Oil line mainly includes pilot oil line and main oil line. The flow of pilot oil line controls the flow of
the main oil line to make sure the variation of oil flow from main line to steering cylinder in some
ratio, so that the small flow with low pressure can control large flow with high pressure, as a result,
the steering operation is handy and flexible. Safety valve is on the flow amplification valve, the
system pre-set pressure is 14MPa.
When the system working pressure of working equipment is below 16MPa, the hydraulic oil of
steering system will flow through PF port of flow amplification valve, unload valve and will converge
with the oil of working equipment hydraulic system to let working equipment hydraulic system
achieve large flow with low pressure working. When the system working pressure of working
equipment is above 16MPa, unload valve will unload. The working equipment can get oil supply only
from working pump, so that to achieve small flow working with high pressure.
3 Brake System
Brake system is used when the machine decelerates even stops or the long-term parks on the level
ground or incline. The brake system of this machine is composed of driving brake system, emergency
and parking brake system.
1-Air booster pump 2-Shuttle valve 3-Air brake valve
4-Air tank
5-Combination valve of oil water Separator
6-Air compressor
7-Braking electromagnetic valve 8- Parking brake air room
Figure 5-3 LG968/969 Braking Sytem Theory
