TROUBLESHOOTING WITHOUT A DIAGNOSTIC CODE - CONTINUED
Table 7. Hydraulic System Troubleshooting.
TEST OR INSPECTION
WARN I N G
Injury or death to personnel can result from sudden machine move-
DO NOT disconnect or remove any hydraulic system line or fitting
unless engine is shut down and hydraulic system pressure has been
relieved. Tighten all connections before applying pressure. Escaping
hydraulic fluid under pressure can penetrate skin, causing injury to
At opening temperature, hydraulic oil is hot. Allow hydraulic oil to
cool before disconnecting any hydraulic lines. Failure to follow this
warning may result in injury to personnel.
To prevent injury to personnel, wear protective eye covering and
CAU T I ON
Wipe area clean around all connections to be opened during removal. Cap
lines and hoses and plug openings after removing lines. Contamination of
system could result in premature failure.
N OT E
Tag hoses prior to removal to ensure correct installation.
Use a container to catch any fluid that may drain from hoses or sys-
tem. Dispose of fluid IAW local policy and ordinances. Ensure all
spills are cleaned up.
On 924G machines, each valve has poppets which act as load check
valves. Poppets close ports so there is almost zero drift of imple-
ments. Relief valves in auxiliary circuit and in tilt circuit protect
components from pressures in circuits when control valves are in
Oil Pressure for opening relief valves for main system and auxiliary
circuits must be within specifications. Pressures that are too low will
cause a decrease in lifting force and dig characteristics. Pressures that
are too high will cause a decrease in life of hose and other components.
Circuit drift is caused by leakage past cylinder pistons, O-ring seals in
control valves, check valves that do not seat correctly, or makeup
valves that do not seat correctly. Poor adjustments of control valves or
incorrect fit may also contribute to circuit drift.
Cycle times that are longer than normal can result from oil leakage,
pump wear, or pump speed.
If basic tests indicate a leak in circuit, install a flow meter and per-
form a test.
Many of these problems can create diagnostic or event codes in ET.
These codes can help find the root cause of a problem. ET should be
used to retrieve logged and active codes.