Large Shock Is Made When Upper Structure Stops Swinging; Large Sound Is Made When Upper Structure Stops Swinging - Komatsu PC130-7 Shop Manual

TROUBLESHOOTING
H-25 Large shock is made when upper structure stops swinging
Trouble

• Large shock is made when upper structure stops swinging.

Related
• Carry out the troubleshooting in working mode A.
information
Malfunction of swing PPC
1
Possible causes
valve
and standard
value in normal
state
Malfunction of swing PPC
2
slow return valve
Malfunction of swing motor
3
(shockless valve)
H-26 Large sound is made when upper structure stops swinging
Trouble

• Large sound is made when upper structure stops swinging.

Related
• Carry out the troubleshooting in working mode A.
information
Malfunction of back-pres-
1
sure check valve
Malfunction of swing motor
Possible causes 2
(safety valve)
and standard
value in normal
Malfunction of swing motor
state
3
(suction valve)
4 Defective swing machinery
20-524
(1)
Cause Standard value in normal state/Remarks on troubleshooting
aPrepare with engine stopped, then run engine at high idling and carry
out troubleshooting.
Right work equipment control lever
The swing PPC slow return valve may have a malfunction. Check it
directly.
The shockless valve of the swing motor may have a malfunction. Check
it directly.
Cause Standard value in normal state/Remarks on troubleshooting
The back-pressure check valve may have a malfunction. Check it
directly.
The swing motor (safety valves) may have a malfunction. Check it
directly. (It may be checked by exchanging both valves and seeing the
change of phenomenon.)
The swing motor (suction valves) may have a malfunction. Check it
directly. (It may be checked by exchanging both valves and seeing the
change of phenomenon.)
The swing machinery may have a defect in it. Check it directly. (It may
be checked by abnormal sound, abnormal heating, metal chips in drain
oil, etc.)
In NEUTRAL position
In SWING position
H-25, H-26
PPC valve output pressure
0 MPa
2
{0 kg/cm }
2.84 – 3.43 MPa
2
{29 – 35 kg/cm }
PC130-7