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Section E
51 - 2
Dismantling and Assembly
Precision Control (Servo)
(Machines from January 2003)
Dismantling
The loader valve block is a 'sandwich type', which is made
up of a number of separate sections. The illustration shown
on the opposite page is intended as a guide to dismantling.
Be sure to note the location of all components when
dismantling. Although some components may appear to be
identical they are not interchangeable. Make sure that
components are assembled in their original positions.
1
Remove the loader valve block from the machine.
2
Remove the three tie rod nuts 1.
3
Carefully separate and remove the end plate 2 followed
by the remaining service sections 3. If the inlet section 4
is to be replaced, remove and retain the tie rods 5.
Assembly
Assembly is the reverse of the dismantling sequence.
1
Clean the valve components in an appropriate solvent.
Ensure that the mating faces of the valve sections are
thoroughly clean before assembly.
2
Renew the 'O' rings located between the valve sections.
Make sure the 'O' ring seals are not trapped or
damaged.
3
Lubricate parts with JCB Hydraulic Fluid before
assembling. Make sure that all the parts move freely.
Torque Settings
Item
Nm
kgf m
1
35
3.6
7A
10
1
7B
10
1
7C
10
1
7D
10
1
8A
20
2
8B
10
1
8C
10
1
8D
10
1
9A
10
1
9B
10
1
9C
10
1
10
70
7.1
10A
70
7.1
11
60
6.1
12
30
3
9803/3280
Hydraulics
Loader Valve - Fixed Flow
lbf ft
25.8
7.4
7.4
7.4
7.4
14.8
7.4
7.4
7.4
7.4
7.4
7.4
51.6
51.6
44.3
22.1
Purchased from www.WorkshopManuals.co.uk
Service Spools
Care must be taken to ensure that the spools 6 are not
damaged when removing them from the block. Note that all
spools may be similar in appearance but must not be
interchanged as they are matched to their bores.
Standard Spool
The dismantling and assembly procedures for the standard
spool assembly 7 are detailed separately, refer to Standard
Spool.
Electric Detent Spool
The dismantling and assembly procedures for the electric
detent spool assembly 8 are detailed separately, refer to
Electric Detent Spool.
Mechanical Detent Spool
The dismantling and assembly procedures for the
mechanical detent spool assembly 9 are detailed separately,
refer to Mechanical Detent Spool.
Auxiliary Relief Valves
The A.R.V's 10 appear identical but have various pressure
settings, refer to Technical Data. Ensure that they are
correctly adjusted and fitted in their specified positions.
The dismantling and assembly procedures for the ARV's are
detailed separately, refer to Excavator Valve, Dismantling
and Assembly - Auxiliary Relief Valves (ARV's).
Pressure Compensator Valves
Each of the pressure compensator valves 11 can be
removed as shown. Note that all valves are identical in
appearance. Note that components are not interchangeable.
Load Hold Check Valves
Each of the load hold check valves 12 can be removed as
shown. Note that all valves are identical in appearance.
Ensure good condition of seating faces on poppets and on
the mating faces in the valve block.
Section E
51 - 2
Issue 1
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