Hyundai Excavator R450LC-7. Service and repair manual - page 27

8-35-21

Remove lever(1, 612).  Do not draw out
pin(875).

Draw out pilot piston(643) and spool(652).

Draw out piston case(622), compensating
piston(621) and compensating rod(623).
Piston  case(622) can  be taken out  by
pushing compensating rod(623) at
opposite side of piston case.

This completes disassembly.

(11)

(12)

(13)

※

ASSEMBLY

For assembly, reverse disassembly
procedures, but pay attention to the
following items.

Always repair parts that were scored at
disassembly.
Get replacement parts ready before-
hand.
Mixing  of  foreign  matter  will   cause
malfunction.
Therefore, wash parts well with cleaning
oil, let them dry with jet air and handle
them in clean place.
Always tighten bolts, plugs, etc.   to their
specified torques.
Do  not  fail to coat  sliding  surfaces  with
clean hydraulic oil before assembly.
Replace seals such as O-ring with new
ones as a rule.

(1)

①

②

③

④

⑤

4

4

)

Put compensating rod(623) into compen-
sating hole of casing(601).

Put pin force-fitted in lever(1, 612) into
groove of compensating rod and fit lever
(1) to pin force-fitted in casing.

(2)

(3)

Fit spool(652) and sleeve(651) into hole in
spool of casing.
Confirm that spool and sleeve slide
smoothly in casing without binding.
Pay attention to orientation of spool.

(4)

※

※

8-35-23

Lever (1) side

Lever (2) side

(Fulcrum plug of

adjusting plug side)

Fit return spring(654) and spring seat
(653) into spool hole and attach snap ring
(814).

(10)

Fit fulcrum plug(614) so that pin force-
fitted in fulcrum plug(614) can be put into
pin hole of lever(2).  
Then fix locking ring(858).

Insert adjusting plug(615) and fit locking
ring.
Take care not to mistake inserting holes
for fulcrum plug and adjusting plug.
At this point in time move feedback lever
to confirm that it has no large play and is
free from binding.

(8)

(9)

※

Put pilot piston(643) into pilot hole of
casing.
Confirm that pilot piston slides smoothly
without binding.

Put pin force-fitted in lever(2, 613) into
groove of pilot piston.
Then fix lever(2).

(6)

※

(7)

Fit feedback lever(611), matching its pin
hole with pin hole in spool.
Then insert pin(874).
Insert pin in feedback lever a little to ease
operation.
Take care  not to mistake  direction  of
feedback lever.

(5)

※

※

8-28 (210-7)

REG11 (210-7)

REG12 (210-7)

REG13 (210-7)

8-35-24

Install cover(C, 629) fitted with adjusting
screws(628, 925), adjusting ring(C, 627),
lock nut(630), hexagon nut(801) and
adjusting screw(924).
Then tighten them with hexagonal socket
head screws(438).

This completes assembly.

(13)

Put spring seat(644), pilot spring(646) and
adjusting ring(Q, 645) into pilot hole.
Then fix spring seat(624), inner spring
(626) and outer spring(625) into compen-
sating hole.
When fitting spring seat, take care not to
mistake direction of spring seat.

(12)

※

Fit set spring(655) to spool  hole and  put
compensating piston(621) and piston
case(622) into compensating hole.
Fit pilot cover(641) and tighten it with
hexagonal socket head screws(436, 438).

(11)

REG14 (210-7)

REG15 (210-7)

REG16 (210-7)

8-36

1. REMOVAL AND INSTALL

REMOVAL

Lower the work equipment to the ground
and stop the engine.

Operate the control levers and pedals
several times to release the remaining
pressure in the hydraulic piping.

Loosen the breather slowly to release the
pressure inside the hydraulic tank.
Escaping  fluid  under  pressure  can
penetrate  the  skin  causing  serious
injury.
When pipes and hoses are disconnected,
the oil inside the piping will flow out, so
catch it in oil pan.

Remove bolts and disconnect pipe.

Disconnect pilot line hoses.

Disconnect pilot piping.

Sling the control valve assembly and
remove the control valve mounting bolt.

·

Weight : 420kg(930lb)

Remove the control valve assembly.
When removing the control valve
assembly, check that all the piping have
been disconnected.

I

I

NSTALL

Carry out installation in the reverse order
to removal.

Bleed the air from below items.

Cylinder(Boom, arm, bucket)
Swing motor
Travel motor
See each item removal and install.

Confirm the hydraulic oil level and recheck
the hydraulic oil leak or not.

GROUP  4   MAIN CONTROL VALVE

1)

(1)

(2)

(3)

※

(4)

(5)

(6)

(7)

(8)

2)

(1)

(2)

①
②

③
※

(3)

45078MC01

45078MC02

45078MC03

13031GE18

8-37

2. STRUCTURE(1/3)

20

Spool assy

21

Spring seat

22

Spring

23

Plug

24

Spool assy

25

Spring

26

O-ring

27

Plug

29

Spring

30

Poppet

49

Relief valve kit

50

Relief valve assy

51

Plug assy

52

Poppet

53

Spring

54

Plug

55

O-ring

58

Plug assy

59

Plug assy

60

Plug assy

61

Plug assy

62

Plug assy

65

Bolt

69

Poppet

72

Relief valve kit

73

Relief valve kit

76

O-ring

77

O-ring

78

O-ring

79

O-ring

86

Socket head bolt

45078MC04

8-38

STRUCTURE(2/3)

2

Housing

6

Spool assy

8

Spool assy

9

Spool assy

10

Spool assy

11

Spool assy

12

Cap

13

Cap

14

O-ring

15

Poppet

16

Spring

17

Spacer

18

O-ring

19

Back up ring

31

Poppet

32

Poppet

33

Spring

34

Flange

35

O-ring

36

Poppet assy

37

Spring

38

Sleeve

39

Piston

40

O-ring

41

Back up ring

42

Body

43

Piston

44

Flange

45

O-ring

46

Poppet

47

Body assy

48

Relief valve assy

56

Flange

57

O-ring

60

Plug assy

63

Bolt

64

Bolt

68

Bolt

77

O-ring

83

Flange

84

Bolt

85

O-ring

87

Bolt

45078MC05

8-39

STRUCTURE(3/3)

1

Housing

3

Spool assy

4

Spool assy

5

Spool assy

6

Spool assy

7

Spool assy

12

Cap

13

Cap

14

O-ring

15

Poppet

16

Spring

17

Spacer

18

O-ring

19

Back up ring

28

Poppet

29

Spring

31

Poppet

33

Spring

34

Flange

35

O-ring

46

Poppet

47

Body assy

56

Flange

61

Plug assy

63

Bolt

64

Bolt

77

O-ring

80

Cap

81

Cap

82

Steel ball

84

Bolt

45078MC06

8-42

4. DISASSEMBLY AND ASSEMBLY

GENERAL PRECAUTIONS

All hydraulic components are manufactured to a high precision.  Consequently, before
disassembling and assembling them, it is essential to select an especially clean place.

In handling a control valve, pay full attention to prevent dust, sand, etc. from entering into it.

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.

Support the body section carefully when carrying or transferring the control valve.  Do not lift by
the exposed spool, end cover section etc.

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.

1)

(1)

(2)

(3)

(4)

(5)

8-47

ASSEMBLY

General comments

In this assembly section, explanation only is shown.
For further understanding, please refer to the figures and photographs shown in the previous
disassembly section.
Figure in (  ) shown after the part name in the explanation refers to the reference identity number
shown on the construction figure shown in the spares section.
Cautions in assembling seal

Pay close attention to keeping all seals free from handling damage and inspect carefully for
damage before using them.
Apply clean grease or hydraulic oil to the seal so as to ensure it is fully lubricated before
assembly.
Do not stretch seals so much as to deform them permanently.
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.
Tighten fitting bolts for all sections with a torque wrench adjusted to the respective tightening
torque as shown on the corss section drawings of the spares section.

Main spool

Apply loctite to thread of spools(3, 4, 6, 7, 9, 10, 11) and assemble spring seat, spring and spool
end.  Assemble spool end to spool after fixing spool with a vise attached wood.
Be careful not to applying loctite too much.

·

Tightening torque : 2.4 ~ 2.6 kgf

·

m(17.4 ~ 18.8lbf

·

ft)

Fit O-ring into housing and assemble spools(3, 4, 6, 7, 9, 10, 11) into housing.
Assemble lock cap on housing and tighten hex socket bolt.

·

Tightening torque : 11

±

0.5 kgf

·

m(79.7

±

3.7lbf

·

ft)

Insert poppet, spring into spool(5) and then apply loctite to thread of spool. 
Fit O-ring and backup ring on the plug and then tighten plug.
Assemble spring seat, spring, and spool end and then assemble spool end sub assy to spool
after fixing spool with a vise attached wood.

·

Tightening torque : 2.4 ~ 2.6 kgf

·

m(17.4 ~ 18.8lbf

·

ft)

Fit O-ring into housing and assemble spool(5) into housing.
Assemble lock cap on housing and tighten hex socket bolt.

·

Tightening torque : 11

±

0.5 kgf

·

m(79.7

±

3.7lbf

·

ft)

Insert poppet, spring into spool(8) and then apply loctite to thread for spool.
Fit O-ring and backup ring on the plug and then tighten plug.
Assemble spring seat, spring, and spool end and then assemble spool end sub assy to spool
after fixing spool with a vise attached wood.

·

Tightening torque : 2.4 ~ 2.6 kgf

·

m(17.4 ~ 18.8lbf

·

ft)

Fit O-ring into housing and assemble spool(8) into housing.
Assemble lock cap on housing and tighten hex socket bolt.

·

Tightening torque : 11

±

0.5 kgf

·

m(79.7

±

3.7lbf

·

ft)

Assemble short cap on housing and tighten hex socket bolt.

·

Tightening torque : 11

±

0.5 kgf

·

m(79.7

±

3.7lbf

·

ft)

3

3

)

(1)

①

②

③

③

(2)

①

※

②

③

④

a.

b.

c.

d.

e.