Hyundai Excavator R450LC-7. Service and repair manual - page 36

8-149-1

DISASSEMBLY(#0262~)

Remove cylinder head and piston rod

Procedures are based on the bucket
cylinder.
Hold the clevis section of the tube in a
vise.
Use mouth pieces so as not to damage
the machined surface of the cylinder
tube. Do not make use of the outside
piping as a locking means.

200mm

Full straight

sideways

Lift

Oil pan

(1)

※

①

※

Draw out cylinder head and rod assembly
together from tube assembly(1).
Since the rod assembly is heavy in this
case, lift the tip of the rod assembly(2)
with a crane or some means and draw it
out. However, when rod assembly(2)
has been drawn out to approximately
two thirds of its length, lift it in its center to
draw it completely.

④

※

Loosen and remove socket bolts(22) of
the gland in sequence.
Cover the extracted rod assembly(2) with
rag to prevent it from being accidentally
damaged during operation.

③

※

Pull out rod assembly(2) about 200mm
(7.1in). Because the rod assembly is
rather heavy, finish extending it with air
pressure after the oil draining operation.

②

36078CY21A

4507A8CY01

36078CY21C

8-149-2

Rod assembly

Wooden block

Remove piston and cylinder head
(R450LC-7A)

Remove lock nut(21).
Since lock nut(21) and lock washer(20)
is tightened to a high torque, use a
hydraulic and power wrench that utilizers
a hydraulic cylinder, to remove the lock
nut(21) and lock washer(20).
Remove piston assembly(14), back up
ring(16), and O-ring(15).

Place the removed rod assembly on a
wooden V-block that is set level.
Cover a V-block with soft rag.

⑤

※

Note that the plated surface of rod
assembly(2) is to be lifted. For this
reason, do not use a wire sling and
others that may damage it, but use a
strong cloth belt or a rope.

((2)

①
※

②

36078CY22A

470078CY01

20 21

Remove piston and cylinder head
(R500LC-7A)

Remove screw(21) and lock nut(20).
Since lock nut(20) is tightened to a high
torque use a hydraulic and power
wrench that utilizers a hydraulic cylinder,
to remove the lock nut(20).
Remove piston assembly(14), back up
ring(16), and O-ring(15).

(3)

①
※

②

50078CY02

8-149-3

Pull straight

Lift with a crane

Plastic

hammer

Remove the cylinder head assembly
from rod assembly(2).
If it is too heavy to move, move it by
striking the flanged part of cylinder head
with a plastic hammer.
Pull it straight with cylinder head
assembly lifted with a crane.
Exercise care so as not to damage the lip
of rod bushing(4) and packing (6, 7, 8, 9,
10) by the threads of rod assembly(2).

③

※

36078CY22C

Disassemble cylinder head assembly

Remove back up ring(12) and O-ring
(11).
Remove snap ring(10), dust wiper(9).
Remove back up ring(7), rod seal(6) and
buffer ring(8).
Exercise care in this operation not to
damage the grooves.
Do not remove seal and ring, if does not
damaged.

(4)

①

②
③

※

Disassemble the piston assembly

Remove wear ring(18).
Remove dust ring(19) and piston seal
(17).
Exercise care in this operation not to
damage the grooves.

(3)

①
②

※

50078CY03

50078CY04

8-149-4

Press here

(Straight down)

Metal

Right

Wrong

Rod seal(6) has its own fitting direction.
Therefore, confirm it before fitting them.
Fitting rod seal(6) upside down may
damage its lip. Therefore check the
correct direction that is shown in fig.

※

Fit back up ring(7), rod seal(6) and buffer
ring(8) to corresponding grooves, in that
order.
Coat each packing with hydraulic oil
before fitting it.
Insert the backup ring until one side of it
is inserted into groove.

④

※

Coat dust wiper(9) with grease and fit
dust wiper(9) to the bottom of the hole of
dust seal.
At this time, press a pad metal to the
metal ring of dust seal.
Fit snap ring(10) to the stop face.

②

③

ASSEMBLY

Assemble cylinder head assembly

Check for scratches or rough surfaces if
found smooth with an oil stone.
Coat the inner face of gland(3) with
hydraulic oil.

(1)

※

①

21078DA37

36078CY24A

45078CY11

45078CY24

8-149-5

Fit wear ring(18) and piston ring(19) to
piston(14).

③

Fit piston seal(17) to piston.
Put the piston seal in the warm water of
60~100

。

C for more than 5 minutes.

After assembling the piston seal, press
its outer diameter to fit in.

②
※

※

Fit back up ring(12) to gland(3).
Put the backup ring in the warm water of
30~50

。

Fit O-ring(11) to gland(3).

⑤
※

⑥

Assemble piston assembly

Check for scratches or rough surfaces.
If found smooth with an oil stone.
Coat the outer face of piston(14) with
hydraulic oil.

(2)

※

①

50078CY05

45078CY12

50078CY06

50078CY07

8-149-6

Gland assembly

Rod assembly

Insert

Fit piston assembly to rod assembly.
(R450LC-7A)

Tightening torque : 150

15.0kgf

(1085

108lbf

ft)

⑤

Insert cushion ring(13) to rod assembly.
Note that cushion ring(13) has a direction
in which it should be fitted.

④
※

IInstall piston and cylinder head

Fix the rod assembly to the work bench.
Apply hydraulic oil to the outer surface of
rod assembly(2), the inner surface of
piston and cylinder head.
Insert cylinder head assembly to rod
assembly.

(3)

①
②

③

36078CY26A

50078CY08

Piston assembly

36078CY26C

Fit piston assembly to rod assembly.
(R500LC-7A)

Tightening torque : 100

10kgf

(723

72.3lbf

ft)

⑥

Piston assembly

50078CY09

8-149-7

Straight

Lift

Appply liquid packing

Fix with a bar

Turn clockwise

Place rag

Apply loctite

Overall assemble

Place a V-block on a rigid work bench.
Mount the tube assembly(1) on it and fix
the assembly by passing a bar through
the clevis pin hole to lock the assembly.
Insert the rod assembly in to the tube
assembly, while lifting and moving the
rod assembly with a crane.
Be careful not to damage piston seal by
thread of tube assembly.
Match the bolt holes in the cylinder head
flange to the tapped holes in the tube
assembly and tighten socket bolts to a
specified torque.
Refer to the table of tightening torque.

(3)

①

②

※

③

※

36078CY27A

36078CY27B

Item

Bucket

Boom

Arm

100

723

72.3

723

72.3

723

72.3

kgf

lbf

Fit lock washer(20) and lock nut(21) to
piston(R450LC-7A)

Tightening torque :

⑦

4507A8CY26

Item

Bucket

Boom

Arm

200

5.4

0.5

200

5.4

0.5

200

5.4

0.5

1447

147

39.1

3.6

1447

147

39.1

3.6

1447

147

39.1

3.6

kgf

lbf

Fit lock nut(20) and tighten the screw
(21). (R500LC-7A)

Tightening torque :

⑧

50078CY10

8-150

1. TRACK LINK

REMOVAL

Move track link until master pin is over
front idler in the position put wooden block
as shown.

Loosen tension of the track link.
If track tension is not relieved when the
grease valve is loosened, move the
machine backwards and forwards.

Push out master pin by using a suitable
tool.

GROUP 10 UNDERCARRIAGE

90 ~ 110

(1)

(2)

※

(3)

Master pin

Block

INSTALL

Carry out installation in the reverse order
to removal.
Adjust the tension of the track link.

(1)

※

Move the machine slowly in reverse, and
lay out track link assembly (1).
Jack up the machine and put wooden
block under the machine.
Don't get close to the sprocket side as the
track shoe plate may fall down on your
feet.

(4)

※

8-161(1) 210-7

21074OP14

8-151

2. CARRIER ROLLER

REMOVAL

Loosen tension of the track link.

(1)

Frame

Jack

Carrier roller

Carrier

roller

Grease
valve

INSTALL

Carry out installation in the reverse order
to removal.

(1)

Loosen the lock nut (1).

Open bracket(2) with a screwdriver, push
out from inside, and remove carrier roller
assembly.

Weight : 80kg(180lb)

(3)

(4)

Jack up the track link height enough to
permit carrier roller removal.

(2)

8-162(1) 210-7

8-162(2) 210-7

8-162(3) 210-7

8-152

3. TRACK ROLLER

REMOVAL

Loosen tension of the track link.

(1)

Frame

Grease
valve

90-110

INSTALL

Carry out installation in the reverse order
to removal.

(1)

Remove the mounting bolt(1) and draw
out the track roller(2).

Weight : 80kg(180lb)

(3)

Using the work equipment, push up track
frame on side which is to be removed.
After jack up the machine, set a block
under the unit.

(2)

※

8-163(1) 290-7

8-163(2) 210-7

8-163(3) 210-7

8-153

4. IDLER AND RECOIL SPRING

REMOVAL

Remove the track link.
For detail, see removal of track link.

(1)

2, 3

INSTALL

Carry out installation in the reverse order
to removal.
Make sure that the boss on the end face
of the recoil cylinder rod is in the hole of
the track frame.

(1)

※

Remove the bolts(2), washers(3) and
separate ilder from recoil spring.

(3)

Sling the recoil spring(1) and pull out idler
and recoil spring assembly from track
frame, using a pry.

Weight : 550kg(1210lb)

(2)

8-164(1) 210-7

8-164(2) 210-7

8-164(3) 210-7

8-164(4) 210-7

8-154

DISASSEMBLY AND ASSEMBLY OF IDLER

Structure

(1)

Shell

Bushing

Shaft

O-ring

Seal assembly

Bracket

Spring pin

Plug

36078UC01

8-155

Press

Remove the bushing(2) from idler, using
a special tool.
Only remove bushing if replacement is
necessity.

⑥

※

Pull out the shaft(2) with a press.
Remove seal(5) from shell(1) and
bracket(6).
Remove O-ring(4) from shaft.

③
④

⑤

Disassembly

Remove plug and drain oil.
Draw out the spring pin(7), using a press.

(2)

①
②

8-166(1) 210-7

8-166(2) 210-7

8-166(3) 210-7

8-156

Assembly

Before assembly, clean the parts.
Coat the sliding surfaces of all parts with
oil.
Cool up bushing(2) fully by some dry ice
and press it into shell(1).
Do not press it at the normal temperature,
or not knock in with a hammer even after
the cooling.

(3)

※
※

①

Press

Install shaft(3) to shell(1).

⑤

Install seal(5) to shell(1) and bracket(6).

④

Coat O-ring(4) with grease thinly, and
install it to shaft(3).
Insert shaft(3) into bracket(6) and drive in
the spring pin(7).

②

③

8-167(1) 210-7

8-167(2) 210-7

8-167(3) 210-7

8-167(4) 210-7

8-157

Lay bracket(6) on its side.
Supply engine oil to the specified level,
and tighten plug.

⑧

Knock in the spring pin(7) with a
hammer.

⑦

Install bracket(6) attached with seal(5).

⑥

8-168(1) 210-7

8-168(2) 210-7

8-168(3) 210-7

8-158

DISASSEMBLY AND ASSEMBLY OF RECOIL SPRING

Structure

(1)

Body

Bracket

Rod assembly

Spring

Rod seal

Back up ring

Dust seal

Lock nut

Lock plate

Hex bolt

Spring washer

Grease valve

45078UC02

Content .. 34 35 36 37 ..