Fiat Kobelco EX355 Tier2, Technical Manual

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EX355 T4-5-7
COMPONENT TEST
MAIN RELIEF VALVE SET PRESSURE
Summary:
Measure the main relief valve setting pressure at the
main pump delivery port.
The main relief pressure can also be measured with
Dr.EX.
Preparation:
1. Properly shut down the engine.
2. Press the air release valve on top of the hydraulic
oil tank to release any remaining pressure.
3. Remove the plug from the main pump delivery port.
Install adapter ( 75301519 ), hose ( 75301523 ) and
pressure gauge ( 75301524 ) on the port.
: 6 mm
Or connect Dr.EX to monitor the main pump deliv-
ery pressure.
4. Start the engine. Confirm that no oil leakage is
observed at the pressure gauge connection.
5. Maintain the hydraulic oil temperature at 50 ± 5 °C
(122 ± 9 °F).
Measurement:
1. Select the following switch positions:
Engine E Mode HP Mode Work
Control Switch Switch Mode
Dial Switch
Fast OFF OFF General
Idle Purpose
Mode
2. Slowly operate bucket, arm, and boom control
levers to the stroke ends to relieve each function
one at a time.
3. As for the swing function, secure the upperstruc-
ture so it is immovable. Slowly operate the swing
lever to relieve the swing function.
4. As for the travel function, secure the tracks against
an immovable object. Slowly operate the travel
levers to relieve the travel function.
Evaluation:
Refer to the Performance Standard Table in Group
T4-2.
NOTE: If the measured pressures in all circuits is
lower than the specified range, a decrease in the set
pressure of the main relief valve may be probable
cause.
In cases where the relief pressure of a particular circuit
is lower, the probable cause may be something other
than the main relief valve.
SM6111
Pressure
Check Ports