HYDRAULIC SYSTEM 1300A
2-16 01-22-2019 Control # 051-08
NOTE: If the temperature sensor in the cooling core fails,
the fan runs continuously even when the crane
ignition is off.
Mesh Filter Screen
There is a 100-mesh filter screen (8) (Figure 2-4) in the
crane manifold to protect the HRC pilot circuit from
contamination.
1. Unscrew and remove the screen from the crane
manifold.
2. Clean the screen with kerosene or replace.
3. Insert the screen into the crane manifold and tighten
Hydraulic Valves
Directional Control Valve
The directional control valve controls the hoist, swing, lift
cylinder, and telescope cylinder. The valve is located in an
enclosure on the right side of the turret.
Inspection
Inspect the control valve for visible damage, binding spools,
and evidence of leakage. If excessive internal leakage is
suspected during operation with a spool in its center position,
it is possible that the area between the spool and working
section bore of the valve body is worn beyond serviceable
limits. If this condition exists, the spool and body must be
replaced as an assembly.
Valve Leakage
Dripping hydraulic oil indicates some type of external
leakage. The machine should be removed from service for
immediate repairs. External leaks sometimes develop at
fittings and seals. Spool seals are susceptible since they are
subject to wear. Seals may be damaged by temperatures
that are too high, or by dirt or paint accumulation on the
spool. Damaged seals must be replaced.
A component functioning at reduced efficiency may indicate
that the control valve for that component is leaking internally.
If preliminary check-out reveals that adequate volume is
being supplied to the affected valve bank, relief valves are
properly adjusted, and the component is not at fault, check
the valve for scored or worn parts. Scoring is a usually sign of
contamination (external contamination by dust or internal
contamination by debris from deteriorating components or
oxidized hydraulic oil). Scored or severely worn valve
components must be replaced.
Check valves in the control valve are designed to permit a
flow of hydraulic oil in one direction only. If a piece of dirt or
rust has worked its way into the check valve and lodges
between the poppet and seat, it will keep the valve open and
allow a return flow of hydraulic oil. Clean the valve and check
that the hydraulic system filter is still serviceable.
Binding Spools
Some of the most common causes for stiff spool movement
or jammed spool action are system overheating, excessive
pressure, contaminated or deteriorated hydraulic oil, or
warped mountings. When scorched or deteriorated hydraulic
oil or contamination is the cause, flush the system and
replenish with clean hydraulic oil. If the spool bores are badly
scored or galled, the valve must be removed for servicing.
Warping occurs when mounting plates are not level or they
become distorted from machine damage. The valve can be
shimmed level to correct this problem.
Check the valve for rust. Rust or dirt collecting on the valves
can prevent free movement of the spool, and keep it from the
true center position. Excessive system pressure can create
both internal and external leaks in valves that are otherwise
sound. Only qualified technicians using the correct
equipment should make pressure adjustments when
pressure adjustments are needed.
Directional Control Valve
Removal
1. Tag and disconnect the hydraulic lines from the valve.
2. Cap the lines and plug ports.
3. Loosen and remove the valve mounting bolts and
remove the valve bank.
Fan Relay
Access
Panel
Hydraulic
Oil Cooler
FIGURE 2-11
Cooling Core
To Next Page
Loading...
Need help?
General
