UPPERSTRUCTURE / Pilot Valve IMPORTANT: The quantity of shims (2) has been determined for each port during the performance testing at the factory. Do not lose the shims. Keep the shim carefully in order to install the shim to each former port when assembling. 9. Remove special tool (ST4146). Remove spring guides (7) (4 used), return springs A (5) (2 used), B (6) (2 used), balance springs A (3) (2 used) and B (4) (2 used) from spools (19) (4 used). 10. Remove shim (2) and spacers (1) (4 used) from spools (19) (4 used). 7. When compressing the spring, do not lower the spool. Install special tool (ST 4145) to the port hole on casing (18) as illustrated. : 6 mm ST 4146 18 IMPORTANT:
Spool (19) has been selected to match the hole of casing (18). Replace spool (19) and casing (18) as an assembly. 11. Remove special tool (ST4145) from casing (18). Slowly turn and remove spool (19) from casing (18). IMPORTANT: Retaining ring (22) may come off while disassembling. Do not drop retaining ring (22) inside casing (18). If retaining ring (22) falls inside casing (18), remove retaining ring (22) completely. Retaining ring (22) cannot be reused. 12. Remove retaining ring (22) from casing (18) by using a screwdriver. Install the bolt (M8, Pitch 1.25 mm) to plug (21). Remove plug (21) from casing (18). W178-02-07-048 8.
Install special tool (ST 4146) to the pusher hole on casing (18). Push special tool and compress the spring. Tighten special tool (ST 4146) by using the socket bolt (M14, Pitch 2.0 mm). Remove retaining rings (8)(4 used) from spools (19) (4 used) by using a screwdriver. ST 4145 : 12 mm : 13 mm W2-7-21