17 - 2
Excavator Valve
Dismantling and Assembly
The numerical sequence shown on the illustration is
intended as a guide to dismantling.
For assembly the sequence should be reversed.
Check Valves
Each spool has an identical load hold check valve which can
be removed as shown at 4W. Note only 4W shown on
illustration.
Ensure good condition of seating face on poppet 10 and on
the mating face in the valve block.
Note: All valve block adapters are torqued to 81 Nm (60 lbf
ft; 8.3 kgf m).
Spools
Spools 4B, 4C, 4D, 4E, 4F and 4G are identical but must not
be interchanged as they are matched to their bores. Slew
spool 4A is different in design from the above spools.
All spools have the same centring and sealing components
items 11 to 19 and 24 to 27.
To completely dismantle a spool, follow the sequence 11 to
19 and 24 to 27. To prevent spool rotation when turning
screw 13, hold a rod through the eye end of the spool.
Lubricate new seals with Hydraulic Fluid and take care to
prevent them from being damaged by the sharp edges of
the spool.
Apply JCB Lock and Seal to threads of screw 13.
Torque Settings
Item Nm kgf m lbf ft
1A 17.6 - 20.4 1.76- 2.04 13 - 15
1B 41 - 49 4.2 - 5 30 - 36
11 6.1 - 7.5 0.62 - 0.76 4.5 - 5.5
13 9.5 - 10.9 0.97 - 1.11 7 - 8
Relief Valves
Ensure that A.R.V's 4J to 4T are correctly adjusted and fitted
in their specified positions.
Torque tighten A.R.V's to 41 - 68 Nm (30 - 50 lbf ft, 4.15 -
6.9 kgf m).
The manufacturers do not recommend renewing individual
components of the A.R.V.'s. Each valve should be renewed
as a unit if a component is defective.
Renew all 'O' rings. Lubricate parts with Hydraulic Fluid
before assembly.
The A.R.V's are tested/adjusted on a bench (see page E/15 -
2).
Section E Hydraulics
9803/8550
Section E
17 - 2
Issue 1
Valves
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