Speed Or Power Of Arm Is Low - Komatsu PC130-7 Shop Manual

TROUBLESHOOTING
H-8 Speed or power of arm is low
Trouble

• Speed or power of arm is low.

Related
• Carry out the troubleshooting in working mode A.
information
Malfunction of left PPC
1
valve (boom circuit)
Malfunction of arm control
2
valve (spool)
Possible causes
Malfunction of arm control
and standard
3 valve (pressure compensa-
value in normal
tion valve)
state
Malfunction or defective
4 seal of arm control valve
(suction valve)
Malfunction or defective
5 seal of centralized safety-
suction valve
Malfunction of arm cylinder
6
(cylinder unit)
PC130-7
Cause Standard value in normal state/Remarks on troubleshooting
aPrepare with engine stopped, then run engine at high idling and carry
out troubleshooting.
Left work equipment control lever
The spool of the arm control valve may have a malfunction. Check it
directly.
The pressure compensation valve of the arm control valve may have a
malfunction. Check it directly.
The suction valve of the arm control valve may have a malfunction or a
defective seal. Check it directly.
The centralized safety-suction valve may have a malfunction or a defec-
tive seal. Check it directly.
(A trouble of the centralized safety-suction valve have bad effects on the
boom and bucket.)
aPrepare with engine stopped, then run engine at high idling and carry
out troubleshooting.
Relieved in IN position
Neutral position
Arm IN position
Arm OUT position
Arm cylinder
PPC valve output pressure
0 MPa
2
{0 kg/cm }
2.84 – 3.43 MPa
2
{29 – 35 kg/cm }
Leakage from cylinder
15 cc/min
20-511
H-8
(1)