jcb JS70 Service Manual

60 - 3
Fault Finding
Trouble Causes Solutions
Set pressure is high Back pressure on port T. Adjust the port T back pressure.
Small hole in the Poppet 4 is Dismantle and clean valve,
blocked. reassemble.
Set pressure is low Spring setting 19 Replace the spring or add shim.
Small hole in the Poppet 4 is Dismantle and clean valve,
blocked. reassemble.
Does not relieve pressure Malfunction of the poppet 4 Dismantle and clean valve,
repair/replace if any fault identified.
The leakage value from the ACC Damage to the check seat section 8 Dismantle and clean valve,
port P1 or P2 is more than normal. or contamination. Check the bearing, repair/replace.
Does not return to neutral. Malfunction of the solenoid valve 2 Refer to solenoid valve section.
Malfunction of the spool 18 Dismantle and clean valve,
repair/replace if any fault identified.
Spring 9 defective Replace the spring.
Does not return to neutral. Malfunction of the spool 16 Dismantle and clean valve,
repair/replace if any fault identified.
Spring 7 defective Replace the spring.
During Operation
Set pressure is low Low inlet pressure Adjust the relief valve.
Malfunction of the spool 13 Dismantle and clean valve,
repair/replace if any fault identified.
Spring 21 defective Replace the spring or add shim 1.
Set pressure is high Malfunction of the spool 13 Dismantle and clean valve,
repair/replace if any fault identified.
Back pressure at port T Adjust the port T back pressure.
Malfunction of the solenoid valve 2 Refer to solenoid valve section.
During Locking
No inlet pressure Malfunction of the solenoid valve 2 Refer to solenoid valve section.
The leakage value is more Damage to the seat section Dismantle and clean valve,
than normal. or contamination. Check the bearing, repair/replace.
Defective operation Low voltage Ensure correct voltage.
Malfunction of the solenoid coil 20 Replace coil
Malfunction of the spools 23 and 24 Dismantle and clean valve,
repair/replace if any fault identified.
Spring 6 defective Replace the spring.
Section E Hydraulics
9803/6020
Section E
60 - 3
Issue 1
Multiple Valve
Relief Valve
Check
Valve
Shut off
Valve 1
Shut off
Valve 2
Shuttle
Valve
Solenoid
Valve
Pressure Reducing Valve 2

jcb JS70 Specifications

General

Brand	jcb
Model	JS70
Category	Excavators
Language	English