Hitachi EX20UR-2 Manual page 134

Disassemble Pilot Valves (Front Pilot Valves)
1. First, loosen cam (2), then remove universal joint
(18) from housing (10).
"NI : 50 mm
W554-02-07-003
2. Remove cam (2) and screw joint (1) from universal
joint (18).
W02-06-08
UPPERSTRUCTURE / Pilot Valve
Precautions for Disassembling
1. As housing (10) and spools (9) are precision
parts specially made to fit each other, they must
be replaced as a set. Do not attempt to replace
only one part.
2. Note that ports 1 and 3 and ports 2 and 4 re-
quire different springs, namely springs (7) for
ports 1 and 3, and springs (13) for ports 2 and
4. Take extra care to identify them when disas-
sembling/assembling these parts.
3. Keep disassembled parts separate in port
groups in order not to mix them when reassem-
bling. Port numbers are cast on the periphery of
housing (10).