Maeda MK0003, Service Manual, Page: 98 / 348

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7.6 FAILURES AND COUNTERMEASURES
Details of failure Major cause(s) Remedy
Does not start. Malfunction of hydraulic units other than
traveling motor Check the motor inlet pressure, inspect each
unit and repair or replace as required.
Malfunction of hydraulic motor
･
Breakage of internal parts
･
Leakage of hydraulic oil from check valve
for draining
Replacement of broken parts (kit)
Removal of foreign matters
or replacement of body 1 kit
Malfunction of counter-balanced valve
･
Spool fails to stroke.
Removal of foreign matters
or replacement of body 1 kit
Malfunction of reducer
･
Breakage of internal parts
Replacement of broken parts (kit)
Vehicle speed
cannot be
increased. Malfunction of hydraulic units other than
traveling motor Inspection, repair, or replacement of each
unit
Malfunction of hydraulic motor
･
Drop of volume efficiency caused by
abnormal abrasion due to catching foreign
matters
Replacement of broken parts (kit)
Does not stop,
or delays to stop. Malfunction of counter-balanced valve
･
Return failure of spool
Removal of foreign matters
or replacement of body 1 kit
Brake fails to work
or braking force is
weak.
･
Abnormal abrasion of steel plate, disk plate
or brake piston
Replacement of abraded parts
･
Breakage of spring
Replacement of spring
･
Back pressure is so high that the hydraulic
oil in the braking line cannot be discharged
smoothly.
Review the piping
Oil leakage Damage of O-ring Replacement of O-ring
Breakage of oil seal
･
Outlet pressure of motor is excessively
high.
･
Malfunction of check valve for draining
internal oil
Replacement of oil seal
Review the piping
Removal of foreign matters
or replacement of body 1 kit
Abnormal abrasion of mechanical seal Replacement of floating seat and seal ring