5-27
GROUP 4 DISASSEMBLY AND ASSEMBLY
1. PRIORITY VALVE
STRUCTURE
6
2
5
4
2
3
1
9
7
8
1)
1 Plug
2
Seal ring
3 Orifice
4
Spool
5
Spring
6
Plug
7 Name plate
8 Drive screw
9 Housing
5-28
DISASSEMBLY
Cleanliness is the primary means of
assuring satisfactory the priority valve life.
Select clean place.
Before removing the piping, clean the
surrounding area of valve ports.
3)
Ɠ
Loosen the LS plug using the 22mm open-
end spanner.
(2)
Screw out the PP plug using the 8mm
hexagon socket spanner.
Remove the seal ring.
(1)
PP
LS
TOOLS
şOpen-end spanner 22mm.
şNylon pin.
şHexagon socket spanner 8mm.
şTorque wrench.
şSocket spanner 22mm.
şHexagon socket spanner insert 8mm.
2)
5-29
Disassembled priority valve.
(5)
Press out the spool using the nylon pin.
(4)
LS
PP
Pull out the plug with seal ring and spring.
(3)
LS
5-30
Put in the PP plug.
Remember seal ring.
ASSEMBLY
Guide the spool into the bore. Use the
nylon pin to center the spool in the bore.
(1)
5)
LS
PP
LS
PP
(2)
MODIFICATION
The control spring pressure can be altered by replacing the spring(See table below). Replace
name plate so that code no. and control spring pressure match each other again.
4)
(1)
L
d
Di
Control spring
pressure(bar)
4
7
d(mm)
1.8
2.0
Di(mm)
6.9
6.5
L(mm)
54
55
Cleaning
Clean all parts carefully in low aromatic kerosene.
Inspection and replacement
Check all parts carefully and make any replacements necessary. All seal rings must be replaced.
Lubrication
Before assembly, lubricate all parts with hydraulic oil.
(2)
(3)
(4)
5-31
Guide the spring and LS plug into the
bore.
Remember seal ring.
LS
(3)
Tighten the LS plug with torque wrench
using a 22 socket spanner insert.
şTighten torque : 5.1Ź1kgfşm
(36.9Ź7.2lbfşft)
LS
(4)
Tighten the PP plug with a torque wrench
using a 8mm hexagon socket spanner
insert.
şTighten torque : 5.1Ź1kgfşm
(36.9Ź7.2lbfşft)
(5)
PP
The priority valve is now assembled.
(6)
PP
LS
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TROUBLESHOOTING
6)
Problem
Steering wheel
is heavy
(Steering wheel
is heavy at
engine low idle)
(Steering speed
is