16 - 9
Loader Valve
Dismantling
The illustration opposite shows a typical valve with a
manually operated spool. Valves may have two or three
spool sections depending on equipment fitted. For
dismantling of servo spool section see page E/16-10 and for
solenoid spool section see page E/16-11.
On machines from serial number 678316, a different end cap
incorporating a spool lockout solenoid is fitted to the manual
spools as shown at X. The spool is prevented from moving
unless the solenoid is energised. All other components are
as shown on the main view.
Always work on a clean, dirt free surface.
1 Remove the cap screws and washers 1 and 2. Remove
seal retainer 3 and end cap 4.
On machines after serial number 678316, remove
solenoid 27, remove capscrews 28 and lift off end cap
29.
2 Remove shoulder screw 5 (or 30) from the spool (use a
bar through the eye end of the spool to stop it rotating).
Remove spring seats 6, spacer 7, spring 8 and seal
retainer 9.
3 Remove spool 10. Remove and discard ‘O’ rings 11 and
wiper seals 12.
4 Loosen tie rod nuts 13 at the inlet cover end of the valve
assembly. Position the valve assembly upright on its
outlet cover.
5 Remove tie rod nuts 13 and washers 14. Remove the
inlet cover 15. Identify each section to note the order of
assembly.
6 Carefully separate all the sections from the tie rods.
Discard all inter-section seals 16 and shims 17.
Note: Work on the spool sections individually. Do not
interchange parts from individual sections.
7 Remove check valve guide 18, spring 19 and poppet 20.
Note that the check valves are secured in position by
one of the tie rods.
8 Remove the auxiliary relief valves 21 and 23 (if fitted)
from each spool section. Remove and discard 'O' rings
22 and 24.
9 Remove the main relief valve 25 from the inlet section.
Remove and discard 'O' ring 26.
10 Clean all parts in kerosene, inspect and check for
damage.
Damaged sections should be replaced complete.
Assembly
Assembly is a reversal of the dismantling procedure.
Renew all seals and 'O' rings.
Lubricate all parts with hydraulic oil before assembly.
On machines after serial number 678316, apply 2 or 3 drops
of JCB Threadlocker & Sealer to threads of shoulder bolt 30
after degreasing threads.
Ensure that the spools are inserted in their correct bores.
Before finally tightening tie rod nuts 13, position the valve
assembly on its mounting feet and ensure the valve is sitting
flat.
On machines after serial number 678316, check operation of
lock-out solenoid 27 after assembly. With the solenoid de-
energised the spool should be locked in the neutral position.
Connect a 12 volt electrical supply to the solenoid and check
for free spool operation. Carry out check three times to
confirm correct operation.
Torque Settings
Item Nm lbf ft kgf m
1 & 2 5 - 8 4 - 6 0.5 - 0.8
5 5 - 8 4 - 6 0.5 - 0.8
13 26 - 28 19 - 21 2.6 - 2.8
21 20 - 24 15 - 18 2.0 - 2.5
23 20 - 24 15 - 18 2.0 - 2.5
25 20 - 24 15 - 18 2.0 - 2.5
27 20 - 24 15 - 18 2.0 - 2.5
28 9 - 12 7 - 9 1.0 - 1.2
30 5 - 8 4 - 6 0.5 - 0.8
Section E
Hydraulics
9803/8500
Section E
16 - 9
Issue 2*
Valves
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