Dismantling and Assembly
Auxiliary Relief Valves
Eight A.R.V's are fitted at positions
4H
to
4Q.
These are
identical in design but have various pressure settings, refer
to
Technical Data
.
Note:
Valve
4Q
is only fitted to machines equipped with a
Powerbreaker.
The numerical sequence shown on the illustration is intended
as a guide to dismantling.
For assembly the sequence should be reversed.
Dismantling
Dismantle sub-assembly
14
from item
1
using a special tool
(see
Service Tools
). The special spanner locates in cross
holes
B
.
Dismantle sub-assembly
14
into its component parts.
Make sure that small drilling
A
is not blocked.
Discard old and worn O-rings and back-up rings.
Assembly
Renew all O-rings and back-up rings.
Lubricate O-rings and back-up rings with JCB Hydraulic
Fluid.
Fit back-up ring
13
on the upper side of 'O' ring
12
as shown
in the inset.
Fit flat face of sleeve
9
against shoulder of poppet
10.
Torque tighten item
14
using the special tool (see
Service
Tools
), until its shoulder seats firmly against item
1
.
Pressure test the relief valves, refer to
Service Procedures,
Excavator Valve - Pressure Testing
.
Torque Settings
Item
Nm
kgf m
lbf ft
1
65
6.6
48
3
24
2.5
18
A.R.V. Position Key
Control Layout
JCB
ISO
Case
Ford
Slew Right
4H
4H
4H
4H
Slew Left
4J
4J
4J
4J
Boom Rod
4K
4M
4M
4K
Boom Head
4L
4N
4N
4L
Dipper Rod
4N
4L
4K
4N
Dipper Head
4M
4K
4L
4M
Bucket Rod
4Q
4Q
4Q
4P
Bucket Head
4P
4P
4P
4Q
Note:
The bucket rod side A.R.V. is only fitted to machines
equipped with a Powerbreaker.
61 - 4
Section E
9803/3280
Section E
61 - 4
Issue 2*
Excavator Valve