Dismantling And Assembly - jcb JS300 Service Manual

Dismantling
Note: All parts are precision made and require the utmost
care when being handled.
Note: During dismantling, do not use excessive force to
separate components which could cause scratches or
burrs on bearing surfaces. Failure to observe this
instruction will cause
performance.
Note: Label all parts during dismantling, to ensure correct
assembly.
Note: Storing the valve when dismantled could cause
rusting of parts. Ensure they are suitably protected by anti-
rust treatment.
Note: Refer to the illustration for part number identification
K Fig 4. ( T
E-104).
1 Push down upper section of gaiter 19 and remove roll
pin 20.
2 Remove control handle from mounting knuckle 3.
Note: Take care when removing handle to avoid damage
to wiring loom and switches. These should be removed by
separating the line connectors in the control handle and
below the valve body.
3 Remove gaiter 19 from valve housing.
4 Slacken locknut 22 and remove mounting knuckle 23.
5 Slacken and remove joint nut 24 and rocker plate 25.
!M
WARNING
Always wear safety glasses when dismantling
assemblies containing components under pressure
from springs. This will protect against eye injury from
components accidentally flying out.
GEN-6-2
Note: The return spring 15, retaining plate 18 and plunger
11 will rise when knuckle joint 26 is loosened.
6 Using a jig, slacken and unscrew knuckle joint 26,
releasing retaining plate 18.
E-102

Dismantling and Assembly

oil leaks leading to
Note: Ensure retaining plate moves freely to prevent
sudden release due to spring pressure beneath.
7 Clean the valve exterior using approved solvent and
using soft metal pads for protection, clamp the valve
body into a vice.
8 If the return springs 15 are weak, the sliding
resistance of the seal 9 will cause the guides 8 to stick
poor
in the casing. Using a screw driver, carefully ease out
the guides 8 and plungers 11.
Note: Care must be taken to prevent damage to the guides
when removing. Ensure the guides do not fly out due to the
force of the return springs.
9 Remove spring seats13, split washers 12, return
springs 15, pressure control springs 14 and spools
17.
Note: Identify each set of parts and their locations for
assembly.
10 Loosen the two hex bolts 27 on the base of the valve.
Remove the base plate and `O'-ring 30 from the valve
casing.
11 Slacken and remove body assembly screw 6.
Remove and discard `O'-ring 7.
12 Separate upper and lower body sections 1 and 2 and
remove dowel pins 5.
13 Remove and discard `O'-rings 3 and 4.
Note: The surface of spool 17 and spring 13 can be
damaged by mis-handling. Take care not to damage the
surface of the spool during removal and do not push the
spring seat down more than 6mm (0.24 in).
14 Hold spools 17 firmly on the work bench and depress
spring seat 13 and remove split washers 12.
Note: Avoid scratching the surface of the spools. Do not
depress the spring seats more than 6 mm (0.24 in).
15 Separate spools 17, spring seats 13, springs 14 and
15 and shims 16.
16 Remove plungers 11 from guides8.
9813/5100-1
Section E - Hydraulics
Hydraulic Control Levers
Dismantling and Assembly
E-102