Komatsu PC58UU-3 User Manual

TROUBLESHOOTING H-6
PC58UU-3
20-517
1
a) Boom RAISE speed or power is low
★
When measuring the boom RAISE relief pressure, reset the interference prevention system.
★
When the boom speed is low, if the result of troubleshooting No. 1 is [NO], take actions against the
relief pressure and carry out troubleshooting No. 2.
H-6 Boom speed or power is low (Other work equipment is nor-
mal)
Cause Remedy
1
• 26.5
+1.0
- 0.5
MPa
{265
+10
-5
kg/cm²}
• Run engine at full throttle
Is boom relief pressure normal?
No
Yes
2
• 2.45 MPa {25 kg/cm²}
• Run engine at full throttle
Is EPC valve output pressure normal
(at PPC pressure inlet of control
valve?
No
Yes
3
Does control valve spool move
smoothly?
No
Defective operation of con-
trol valve spool
Repair or
replace
Yes
4
Does pressure compensation valve
move smoothly?
No
Defective pressure compen-
sation valve
Repair or
replace
Yes
5
• 26.5
+1.0
- 0.5
MPa
{265
+10
-5
kg/cm²}
• Run engine at full throttle
Is boom LOWER relief pressure nor-
mal?
No
Defective centralized safety
valve
Replace
Yes
Defective suction valve
(Boom RAISE side)
Repair or
replace
6
When pilot hose of boom assist valve
is disconnected, is speed increased?
No
Defective boom cylinder
packing
Repair or
replace
Yes
Defective seat of check valve
of boom assist valve
Repair or
replace
7
(Move arm IN and RAISE
boom)
When PPC hose of control valve is
replaced with arm IN hose, is trouble
repaired? (Return hose immediately
after checking.)
No
Go to troubleshooting No. 3 —
Yes
• 2.94
+ 0.5
- 0.1
MPa
{30
+ 5
- 1
kg/cm²}
• Run engine at full throttle
• Measure at solenoid valve
inlet
8
Is PPC valve output pressure normal?
No
Defective boom RAISE PPC
valve
Repair or
replace
Yes
Defective boom RAISE EPC
valve
Repair or
replace

Komatsu PC58UU-3 Specifications

General

Brand	Komatsu
Model	PC58UU-3
Category	Construction Equipment
Language	English