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
Hydraulics
9803/3280
Section E
61 - 4
Issue 2*
Excavator Valve
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