Method For Releasing Internal Pressure In Hydraulic Circuit; Check Nitrogen Gas Charge Pressure In Accumulator (Control Circuit); Check Nitrogen Gas Charge Pressure In Accumulator (Control Circuit) - Komatsu PC130-7 Operation & Maintenance Manual

MAINTENANCE PROCEDURE

METHOD FOR RELEASING INTERNAL PRESSURE IN HYDRAULIC CIRCUIT

q The hydraulic system is always under internal pressure, so when inspecting or replacing the piping or
hoses, always release the pressure in the circuit before starting. If the pressure is not released, high
pressure oil may spurt out and cause serious personal injury.
q The parts and oil are at high temperature after the engine is stopped, and may cause serious burns.
Wait for the temperature to go down before starting the operation.
q When the oil filler cap is removed, oil may spurt out, so turn the cap slowly to release the pressure
before removing the cap.
1. Stop the machine on firm level ground.
2. Within 15 seconds after stopping the engine, operate all
the control levers (work equipment, travel) fully in each
direction to release the internal pressure.
3. Remove cover (1) on top of the hydraulic tank.
4. Loosen oil filler cap (F) at the top of the hydraulic tank
slowly to release the internal pressure.

CHECK NITROGEN GAS CHARGE PRESSURE IN ACCUMULATOR (control circuit)

NOTICE
If the nitrogen gas charge pressure in the accumulator is low and operations are continued, it will become
impossible to release the remaining pressure inside the hydraulic circuit in a failure occurs on the
machine.
Check the nitrogen gas charge pressure as follows.
1. Set the work equipment to maximum reach as shown in the
diagram on the right.
2. Stop the engine and carry out the LOWER operation for the
boom.
3. Check that the tip of the bucket drops at least 1m.
If the tip of the bucket drops less than 1m, the charge pres-
sure inside the accumulator is low, so please contact your
Komatsu distributor.
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WARNING
MAINTENANCE
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