Maeda MC815C - Boom Telescoping Is Slow or Weak; Gear Positions 1 and 2 of Winch Cannot be Shifted

T-422
H-10 [Winch gear positions 1 and 2 cannot be shifted]
Content Gear positions 1 and 2 of winch cannot be shifted
Assumed cause
and action to be
taken
Cause Diagnostic method and action to be taken
1
Crane high-speed solenoid
operation fault
• Check if there are operation faults with the crane high speed
solenoid (travelling / outrigger control valve)
2
Shift position 2 switching
solenoid operation fault
• Check for shift position 2 switching solenoid operation faults
3
Air inclusion in the shift
position 2 switching hose
• With the gear shifted to position 2, loosen the 2-speed shift
hose joint, and vent the air
H-11 [Boom telescoping is slow or weak]
Content Boom telescoping is slow or weak
Assumed cause
and action to be
taken
Cause Diagnostic method and action to be taken
1
Boom telescoping operation
valve (spool) operation fault
• Check for malfunction of the boom telescoping operation
valve spool
2
Boom telescoping cylinder
fault
★ Stop engine to perform preparations and conduct diagnosis
at a high engine idling speed.
•
Boom telescoping cylinder: during retracting relief
Cylinder leakage rate: 10 cc / 10 min
•
Check for malfunction of the boom telescoping cylinder
counter-balanced valve
•
Check for malfunction / deformation in the boom telescoping
cylinder
3 Swivel joint faults Check for internal leakage due to swivel joint faults