Speed Or Power Of Arm Is Low - Komatsu Galeo PC800-8 Shop Manual

SEN00794-02
H-6 Speed or power of arm is low
Failure

• Speed or power of arm is low

phenomenon
• Check that the speeds of the other work equipment, travel, and swing are normal.
(If they are abnormal, carry out the related troubleshooting.)
Relative • Check that the machine does not deviate.
information (If the machine deviates, carry out the related troubleshooting.)
• Carry out all the troubleshooting in working mode P.
• Before carrying out troubleshooting, check that electric circuit related to arm control is normal.
Malfunction of left PPC
1
valve (arm circuit)
Malfunction of arm
2
Possible causes
control valve (spool)
and standard
value in normal
Malfunction of arm
state
3 control valve
(safety & suction valve)
Defective arm control valve
4
(body)
Defective seal of arm
5
cylinder
16
Cause Standard value in normalcy and references for troubleshooting
aPrepare with the engine stopped, then carry out troubleshooting with
the engine at high idle.
L.H. work equipment control lever
Since the spool of the arm control valve (Lo, Hi) may have a malfunc-
tion, check it directly.
The safety-suction valve of the arm control valve (Lo, Hi) may malfunc-
tion. Check it directly. (After checking the safety-suction valve by
exchanging it with a valve of another work equipment circuit, be sure to
return it since its set pressure is different from others.)
Since the body of the arm control valve (Lo, Hi) may have a malfunction,
check it directly.
aPrepare with the engine stopped, then carry out troubleshooting with
the engine at high idle.
L.H. work equipment control lever
Relieved in arm IN position
Arm IN, OUT
Full stroke
40 Troubleshooting
PPC valve output pressure
+0.8
2.9 MPa
–0.2
+8
{30 kg/cm 2 }
–2
Leakage from cylinder
Max. 20 cc/min
PC800, 850-8