GROUP 4 MAIN CONTROL VALVE

1. REMOVAL AND INSTALL OF MOTOR

1) REMOVAL
(1) Lower the work equipment to the ground
and stop the engine.
(2) Operate the control levers and pedals
several times to release the remaining
pressure in the hydraulic piping.
(3) Loosen the breather slowly to release the 13031GE18

pressure inside the hydraulic tank.

Escaping fluid under pressure can
penetrate the skin causing serious injury.
ö When pipes and hoses are disconnected,
the oil inside the piping will flow out, so
catch it in oil pan.
(4) Disconnect hydraulic hose.
A10 A9
B10

(5) Disconnect pilot line hoses. B8

B5
A5
A4

A2

B2

(6) Sling the control valve assembly and

remove the control valve mounting bolt. R27Z97MCV01

ÂWeight : 25 kg (55 lb)

(7) Remove the control valve assembly.
When removing the control valve G
J
F
H

assembly, check that all the piping have

B
D
A

been disconnected.
2) INSTALL
Pa10

(1) Carry out installation in the reverse order Pa8

Pa5

Pa3

to removal. Pb10
Pb8
Pb5
Pb3

(2) Bleed the air from below items.

Η Cylinder (boom, arm, bucket) R35Z77MCV02

Θ Swing motor
Ι Travel motor
ö See each item removal and install. A

(3) Confirm the hydraulic oil level and

recheck the hydraulic oil leak or not.
Pb8'
Pa8
Pa7
Pa6

Pb8 Arm
Ground

Pb7 Boom
Up

Pb5
Pb6

A
R35Z77MCV03

7-22
2. STRUCTURE (1/3)
4-10
4-11 14
4-6
4-9
4-5 4-10
4-12
4-4 4-11
4-8
4-3
4-2
3-6 3-10
4-7 3-5 3-8 25
3-4
4-7 3-3
4-13
4-16 2-6 2-10
4-14 3-7 2-5 2-8
2-4
22
2-3
4-15
1-6
4-17 3-7 16 2-7 1-5
4-18 1-8
1-4
3-2 1-3
1-10
2-7 16 1-7
3-9
2-2
3-10

1-7
2-9
1-2 23
2-10

1-9 24
1-10
1692MC02

1 Dozer work block 2-9 Cover-pilot 4-7 O-ring

1-1 Body-work 2-10 Bolt-soc head w/washer 4-8 Cover-pilot
1-2 Spool assy 3 Swing work block 4-9 Bolt-soc head w/washer
1-3 Poppet 3-1 Body-work 4-10 Plug
1-4 Spring 3-2 Spool assy 4-11 O-ring
1-5 O-ring 3-3 Poppet 4-12 Plug
1-6 Plug 3-4 Spring 4-13 Piston
1-7 O-ring 3-5 O-ring 4-14 O-ring
1-8 Cover-pilot 3-6 Plug 4-15 Body-pilot
1-9 Cover-pilot 3-7 O-ring 4-16 Bolt-soc head w/washer
1-10 Bolt-soc head w/washer 3-8 Cover-pilot 4-17 Orifice
2 Boom swing work block 3-9 Cover-pilot 4-18 Filter-coin type
2-1 Body-work 3-10 Bolt-soc head w/washer 14 Relief valve
2-2 Spool assy 4 Connecting block 16 Plug
2-3 Poppet 4-1 Body-work 17 O-ring
2-4 Spring 4-2 Spool assy 22 O-ring
2-5 O-ring 4-3 Poppet 23 Bolt-tie
2-6 Plug 4-4 Spring 24 Nut-hex
2-7 O-ring 4-5 O-ring 25 Anticavitation valve
2-8 Cover-pilot 4-6 Plug

7-23
 STRUCTURE (2/3)

13

7-8
7-6 15
8 7-4
13
7-3
6-10
6-6
7-5 6-5 6-8
7-1 6-4
19 17 6-3
17 15
6-7 5-6
7-5 5-5
15 6-1
18 5-4
7-2 17 5-3
5-10
6-7 5-7 5-8
7-7 15
18 5-1
6-2
7-8

5-7
6-9 17
18
5-2
6-10

5-9

5-10

1692MC03

5 PTO work block 6-2 Spool assy 7-4 Plug

5-1 Body-work 6-3 Poppet 7-5 O-ring
5-2 Spool assy 6-4 Spring 7-6 Cover-pilot
5-3 Poppet 6-5 O-ring 7-7 Cover-pilot
5-4 Spring 6-6 Plug 7-8 Bolt-soc head w/washer
5-5 O-ring 6-7 O-ring 8 Inlet work block
5-6 Plug 6-8 Cover-pilot 13 Relief valve
5-7 O-ring 6-9 Cover-pilot 15 Overload relief valve
5-8 Cover-pilot 6-10 Bolt-soc head w/washer 17 O-ring
5-9 Cover-pilot 7 Travel work block 18 O-ring
5-10 Bolt-soc head w/washer 7-1 Body work 19 O-ring
6 Arm work block 7-2 Spool assy
6-1 Body-work 7-3 O-ring

7-24
 STRUCTURE (3/3)

117
25
115
119 113
12-10 112 116
12-6 118 114
12-5 12-8 11-6
12-4 12-7 112
11-2 111 120
12-3 11-5 110
107
11-4 102
11-11 101
11-9 104
15 12-1 11-12 106 108 109
17 103
105
12-7 11-10 10-6 10-10
15 20 10-5 10-8
18 10-4
12-2 21
10-3
17 9-6
9-10
9-5
12-9 9-8
11-7 10-7 9-4
11-2 11-1
18 11-8 9-3
12-10 11-3
15
9-7
9-1
10-7 10-1 18 17
10-2

9-7
10-9 17
19
9-2
10-10

9-9

9-10
1692MC04

9 Travel work block 10-8 Cover-pilot 12-3 Poppet 105 Spacer

9-1 Body-work 10-9 Cover-pilot 12-4 Spring 106 Ring-retaining
9-2 Spool assy 10-10 Bolt-soc head w/washer 12-5 O-ring 107 Spring A-lock valve
9-3 Poppet 11 Boom lock valve 12-6 Plug 108 Spring seat
9-4 Spring 11-1 Body-work 12-7 O-ring 109 Pin
9-5 O-ring 11-2 O-ring 12-8 Cover-pilot 110 Poppet
9-6 Plug 11-3 Plug 12-9 Cover-pilot 111 Ring-retaining
9-7 O-ring 11-4 Poppet 12-10 Bolt-soc head w/washer 112 O-ring
9-8 Cover-pilot 11-5 Spring 15 Overload relief valve 113 Guide-piston
9-9 Cover-pilot 11-6 Plug 17 O-ring 114 Piston A1
9-10 Bolt-soc head w/washer 11-7 O-ring 18 O-ring 115 Piston B
10 Boom work block 11-8 Plug 19 O-ring 116 O-ring
10-1 Body-work 11-9 O-ring 20 O-ring 117 Connector
10-2 Spool assy 11-10 O-ring 21 O-ring 118 Ball-steel
10-3 Poppet 11-11 Plug 25 Anticavitation valve 119 Plug
10-4 Spring 11-12 O-ring 101 Cover-lock valve 120 Bolt-hex. socket head
10-5 O-ring 12 Bucket work block 102 Lock valve
10-6 Plug 12-1 Body-work 103 Seal
10-7 O-ring 12-2 Spool assy 104 Filter

7-25
3. DISASSEMBLY AND ASSEMBLY
1) GENERAL PRECAUTIONS
(1) All hydraulic components are manufactured to a high precision. Consequently, before
disassembling and assembling them, it is essential to select an especially clean place.
(2) In handling a control valve, pay full attention to prevent dust, sand, etc. from entering into it.
(3) When a control valve is to be remove from the machine, apply caps and masking seals to all
ports. Before disassembling the valve, recheck that these caps and masking seals are fitted
completely, and then clean the outside of the assembly. Use a proper bench for working. Spread
paper or a rubber mat on the bench, and disassemble the valve on it.
(4) Support the body section carefully when carrying or transferring the control valve. Do not lift by
the exposed spool, end cover section etc.
(5) After disassembling and assembling of the component it is desired to carry out various tests (for
the relief characteristics, leakage, flow resistance, etc.), but hydraulic test equipment is necessary
for these tests. Therefore, even when its disassembling can be carried out technically, do not
disassemble such components that cannot be tested, adjusted, and so on. Additionally one
should always prepare clean cleaning oil, hydraulic oil, grease, etc. beforehand.
2) TOOLS
Before disassembling the control valve, prepare the following tools beforehand.
Name of tool Quantity Size (mm)
Vice mounted on bench (soft jaws) 1 unit
Hexagon wrench Each 1 piece 5, 6, 10, 12 and 14
Socket wrench Each 1 piece 5 and 6
Spanner Each 1 piece 13, 21 and 30
Rod 1 piece Less than 10Ý250

7-26
3) DISASSEMBLY
10
(1) Disassembly of spools (pilot type)
Η Loosen hexagon socket head bolts (10) 8
7
with washer.
(Hexagon wrench : 5 mm)
Θ Remove the pilot cover (8).
ö
Pay attention not to lose the O-ring (7)
under the pilot cover. 1697MC01

Ι Remove the spool assembly (2) from the

body by hand slightly.
ö When extracting each spool from its
body, pay attention not to damage the 2
body.
ö When extracting each spool assembly, it
must be extracted from spring side only.
ö When any abnormal parts are found,
replace it with completely new spool
assembly.
1697MC02
ö When disassembled, tag the
components for identification so that they
can be reassembled correctly.

7-27
(2) Disassembly of holding valve (boom 1)
Η Loosen hexagon socket head bolts(120).
(Hexagon wrench : 5 mm)
120
Θ Remove the holding valve.
ö Pay attention not to lose the O-ring and
the poppet under the pilot cover.
ö
Pay attention not to damage the "piston
A" under pilot cover. 1697MC03
ö When any abnormal parts are found,
replace it with completely new holding
valve assembly.
ö When disassembled, tag the
components for identification so that they Holding valve
can be reassembled correctly.

1697MC04

7-28
(3) Disassembly of the load check valve
and the negative relief valve 6
Η The load check valve
a. Fix the body to suitable work bench.
ö Pay attention not to damage the body.
b. Loosen the plug (6)
(Hexagon wrench : 10 mm).
c. Remove the O-ring (5), spring (4) and 1697MC05

the load check valve (3) with pincers or

magnet.
5
4
3

1697MC06

7-29
(4) Disassembly of the main and overload
relief valve 14

Η Fix the body to suitable work bench.

Θ Remove the main relief valve (14).
(Spanner : 30 mm)
Ι
Remove the overload relief valve (15).
(Spanner : 22 mm)
ö When disassembled, tag the relief valve 1697MC07

for identification so that they can be

reassembled correctly.
ö Pay attention not to damage seat face.
ö When any abnormal parts are found, 15
replace it with completely new relief valve
assembly.

1697MC08

7-30
(5) Disassembly of the block assembly
Η Fix the body to suitable work bench.
Θ Remove the nut (24).
(Spanner : 13 mm)

24

1697MC09

ö Do not removed the tie bolt (23).

23
1697MC10

7-31
(6) Inspection after disassembly
Clean all disassembled parts with clean mineral oil fully, and dry them with compressed air.
Then, place them on clean papers or cloths for inspection.
Η Control valve
a. Check whole surfaces of all parts for burrs, scratches, notches and other defects.
b. Confirm that seal groove faces of body and block are smooth and free of dust, dent, rust etc.
c. Correct dents and damages and check seat faces within the body, if any, by lapping.
ö Pay careful attention not to leave any lapping agent within the body.
d. Confirm that all sliding and fitting parts can be moved manually and that all grooves and path's
are free foreign matter.
e. If any spring is broken or deformed, replace it with new one.
f. When a relief valve does not function properly, repair it, following it's the prescribed disassembly
and assembly procedures.
g. Replace all seals and O-rings with new ones.
Θ Relief valve
a. Confirm that all seat faces at ends of all poppets and seats are free of defects and show
uniform and consistent contact faces.
b. Confirm manually that main poppet and seat can slide lightly and smoothly.
c. Confirm that outside face of main poppet and inside face of seat are free from scratches and so
on.
d. Confirm that springs are free from breakage, deformation, and wear.
e. Confirm that orifices of main poppet and seat section are not clogged with foreign matter.
f. Replace all O-rings with new ones.
g. When any light damage is found in above inspections, correct it by lapping.
h. When any abnormal part is found, replace it with a completely new relief valve assembly.

7-32
4) ASSEMBLY
(1) General precaution
Η In this assembly section, explanation
only is shown.
For further understanding, please refer to
the figures shown in the previous
structure & disassembly section.
Θ Pay close attention to keeping all seals
free from handling damage and inspect
carefully for damage before using them.
Ι Apply clean grease or hydraulic oil to the
seal so as to ensure it is fully lubricated
before assembly.
Κ
Do not stretch seals so much as to
deform them permanently.
Λ
In fitting O-rings, pay close attention not
to roll them into their final position in
addition, a twisted O-ring cannot easily
untwist itself naturally and could thereby
cause inadequate sealing and thereby
both internal and external oil leakage.
Μ
Tighten fitting bolts for all sections with a
torque wrench adjusted to the respective
tightening torque.
Ν
Do not reuse removed O-rings and
seals.
5
4
(2) Load check valve 3
Η Assemble the load check valve (3) and
O-ring (5), spring (4).
Θ Put O-rings on to plug (6).
Ι Tighten plug to the specified torque.
ÂHexagon wrench : 8 mm
ÂTightening torque : 3.7 kgfÂm 1697MC06

(26.7 lbfÂft)

1697MC05

7-33
(3) Main relief, port relief valves
Η Install the main relief valve (14). 14
ÂSpanner : 30 mm
ÂTightening torque : 6 kgfÂm (43.4 lbfÂft)
Θ Install the over load relief valve (15).
ÂSpanner : 22 mm
ÂTightening torque : 4 kgfÂm (28.9 lbfÂft)

1697MC07

15

1697MC08

(4) Main spools

Η Carefully insert the previously assembled
spool assemblies into their respective 2
bores within of body.
ö Fit spool assemblies into body
carefully and slowly. Do not under any
circumstances push them forcibly in.

1697MC02

(5) Covers of pilot type

10
Η Fit spool covers (8) tighten the hexagonal
socket head bolts (10) with washer to the 8
specified torque. 7

ÂHexagon wrench : 5mm

ÂTightening torque : 1~1.1kgfÂm
(7.2~7.9lbfÂft)
ö Confirm that O-rings (7) have been fitted.
1697MC01

7-34
(6) Holding valve
Η Fit the holding valve to the body and
tighten hexagon socket head bolt (120) Holding valve
to specified torque.
ÂHexagon wrench : 5 mm
ÂTightening torque :1.1 kgfÂm (7.9 lbfÂft)

1697MC04

120

1697MC03

7-35