Takeuchi Hydraulic Excavator TB175W (S/N 17540001~). WORKSHOP MANUAL

HYDRAULIC UNITS

PILOT VALVE

IV-95

TB175W

Secondary pressure doesn’t

rise

•

Primary pressure is insufficient

•

Spring is damaged or permanently

deformed

•

The clearance between the spool and

casing is abnormally large

•

There is looseness in the handle

•

Keep the primary pressure

•

Replace the spring

•

Replace the spool and casing assem-

bly

•

Disassemble and reassemble, or re-

place the handle

TROUBLESHOOTING

•

Sliding parts are catching

•

Tank line pressure fluctuates

•

Air gets mixed into the piping

•

Repair or replace

•

Remove the abnormal portions of the

tank line

•

Operate the machine several times

and bleed out the air

•

Tank line pressure is high

•

Sliding parts are catching

•

Remove the abnormal portions of the

tank line

•

Repair or replace

Secondary pressure doesn’t

stabilize

Secondary pressure is high

IV-9

HYDRAULIC UNITS

CYLINDERS

IV-99

TB175W

CYLINDERS

CONSTRUCTION

Boom Cylinder

1. Buffer Ring
2. Rod Packing
3. Dust Seal
4. O-ring
5. Backup Ring
6. O-ring
7. Backup Ring
8. Piston Packing

9. O-ring
10. Tube
11. Bushing
12. Piston Rod
13. Bushing
14. Rod Cover
15. Cushion Bearing
16. Bushing

17. Snap Ring
18. Holder
19. Cushion Seal
20. Collar
21. Piston
22. Wear Ring
23. Nut
24. Set Screw

25. Ball
26. Dust Seal
27. Nipple
28. Plug
29. Grease Nipple
30. Grease Nipple

W2D400E

2 6

5 4

15 2122

23 24 25

18 20

7 4

DETAIL "S"

DETAIL "T"

HYDRAULIC UNITS

CYLINDERS

IV-100

TB175W

Arm Cylinder

1. Buffer Ring
2. Rod Packing
3. Dust Seal
4. Backup Ring
5. O-ring
6. O-ring
7. Backup Ring
8. Piston Packing
9. O-ring

10. Tube
11. Bushing
12. Piston Rod
13. Bushing
14. Rod Cover
15. Cushion Bearing
16. Bushing
17. Snap Ring
18. Holder

19. Cushion Seal
20. Collar
21. Piston
22. Wear Ring
23. Set Screw
24. Ball
25. Cushion Bearing
26. Cushion Seal
27. Snap Ring

28. Stopper
29. Dust Seal
30. Nipple
31. Pipe
32. Plug
33. Holder
34. Bolt
35. Grease Nipple

W2D401E

DETAIL "A"

DETAIL "B"

4 5

15 22 8 2124

23 27 26 25 28

20 7 4

34 33

HYDRAULIC UNITS

CYLINDERS

IV-101

TB175W

Bucket Cylinder

1. Buffer Ring
2. Rod Packing
3. Backup Ring
4. Dust Seal
5. O-ring
6. Backup Ring
7. O-ring
8. O-ring

1. Buffer Ring
2. Rod Packing
3. Backup Ring
4. Dust Seal
5. O-ring
6. Backup Ring

Swing Cylinder

7. O-ring
8. Piston Packing
9. Tube
10. Bushing
11. Piston Rod
12. Bushing

13. Rod Cover
14. Piston
15. Snap Ring
16. Bushing
17. Wear Ring
18. Dust Seal

19. Set Screw
20. Ball
21. Grease Nipple
22. Grease Nipple

9. Piston Packing
10. Tube
11. Bushing
12. Piston Rod
13. Bushing
14. Rod Cover
15. Cushion Bearing
16. Piston

17. Nut
18. Bushing
19. Snap Ring
20. Cushion Seal
21. Cushion Bearing
22. Wear Ring
23. Cushion Seal
24. Stopper

25. Snap Ring
26. Dust Seal
27. Set Screw
28. Ball
29. Grease Nipple

W2D402

5 15

14 17

17 19

18 22

W2D403

2 1 18 19

26 29

7 6

6 8 6

15 20 16 22

27 28 25 23 21 24

HYDRAULIC UNITS

CYLINDERS

IV-102

TB175W

Boom Adjustment Cylinder

1. Buffer Ring
2. Rod Packing
3. Dust Seal
4. O-ring
5. Backup Ring
6. O-ring

7. Piston Packing
8. O-ring
9. Tube
10. Bushing
11. Piston Rod
12. Bushing

13. Rod Cover
14. Bushing
15. Snap Ring
16. Piston
17. Set Screw
18. Ball

19. Dust Seal
20. Plug
21. Holder
22. Grease Nipple
23. Wear Ring

W2D404

DETAIL "A"

HYDRAULIC UNITS

CYLINDERS

IV-103

TB175W

OPERATION

Hydraulic oil flowing alternately in and out of the oil
outlet and inlet on both sides (head and rod sides) of
the piston acts on the piston and its force causes the
piston to move back and forth.
In cylinders equipped with a cushion mechanism, the
shock resulting from the piston colliding with the
cover at the stroke end acts on that mechanism and is
dampened by it.

Cushion Mechanism

When the piston (1) nears the stroke end, just before
it collides with the cover (2), if the cushion bearing (3)
that precedes it enters the inner diameter portion of the
cover, the oil in the back of the piston is restricted by
the cushion bearing (3) and the clearance (4) of the
cover inner diameter portion. This causes the piston’s
(1) back pressure to rise and slows the piston’s speed.

DETAIL PORTION "A"

L1-D406E

HYDRAULIC UNITS

CYLINDERS

IV-104

TB175W

DISASSEMBLY AND ASSEMBLY

Special Tools

See the table of special tools at the back of this section
for the jigs and tools used for disassembly and assem-
bly.

General Cautions

• Carry out disassembly and assembly operations in

a clean place and provide clean containers to place
the disassembled parts in.

• Before disassembly, clean around the ports and

remove the paint from each joint using a wire
brush.

• Clean all disassembled parts in cleaning solvent.

Use a lint free cloth, or air dry the parts.

• Make match marks on each part so that they will be

assembled in the same positions when assembled.

• Replace all seals with new ones each time the

hydraulic units is disassembled.

• Check each part to make sure there is no abnormal

wear or seizing and use sandpaper, etc. to remove
any burrs, sharp edges, etc.

• Do not turn adjusting screws if not required.
• Apply hydraulic oil to sliding surfaces and apply a

thin coating of grease to seals when assembling
them.

In this manual, the procedure for the arm cylinder is
described. When necessary, the points which are
different in other cylinders are mentioned.

Disassembly
Cylinder Assembly

1. Fasten the clevis of the tube in a vice and place the

other end on a support block made of wood to
fasten the cylinder in a horizontal condition.

2. Drain out hydraulic oil remaining in the cylinder.

• Move the piston rod gently to prevent the

hydraulic oil from spraying out and scattering
all over.

3. Free the locked portion of the rod cover.

• Since the lock is integrated with the cylinder

tube, be careful not to bend it or to scratch it
when the lock is being freed.

4. Loosen the rod cover.

• The piston rod should be pulled out approxi-

mately 200 mm beforehand.

• Measures should be taken to prevent the piston

rod from being hit.

HYDRAULIC UNITS

CYLINDERS

IV-105

TB175W

5. Pull the piston rod assembly out of the tube.

• Use a wooden block (1) so as not to scratch the

sliding surface, and pull the assembly straight
out.

Piston Rod Assembly

1. Fasten the piston rod assembly securely in a level

position.

2. Remove the piston.

a. Take out the set screw (2) and remove the steel

ball (3).
• The set screw is staked at 2 places with a

punch, so grind off the staked portions using
a hand drill.

b. Loosen the piston nut (4) and remove it.

• Use a wrench with a hydraulic jack (5).

c. Remove the piston (6).

3. Remove the cushion bearing (7) and cushion seal

(8).

4. Remove the cushion bearing.

a. Remove the snap ring (9).
b. Move the cushion bearing (10) and remove the

stopper (11).

c. Pull out the cushion bearing (10).
d. Remove the cushion seal (12).

5. Remove the rod cover from the piston rod.

HYDRAULIC UNITS

CYLINDERS

IV-106

TB175W

Piston

1. Remove the wear ring (13) from the piston.

• Spread the wear ring the minimum amount

necessary and remove it in the axial direction.

2. Remove the piston packing (14).

• Remove the piston packing by cutting it or

using a screwdriver.

Rod Cover

1. Remove the O-ring (17) and the backup rings (18)

from holder.

2. Remove the collar (30) and cushion seals (29).

3. Remove the O-rings (15), (16) and the backup

rings (20).

4. Remove the buffer ring (19) and rod packing (21).

• Extract using a eyeleteer with a pointed tip.

5. Remove the dust seal (22).

• Extract by raising the rubber part with a screw-

driver, etc., and striking.

6. Remove the snap ring (23).

7. Remove the bushing

• Since the bushing has been pressure fitted

tightly in the rod cover, it is impossible to take
it out. First use a lathe to grind down the inside
portion until only a thin piece remains, then
insert a copper spatula strongly and pry it out
to removed it.

Clevis

1. Remove the dust seal from the tube and piston

rod.

2. Remove the bushing using a setting tool (43).

W2D405

15 19 24

20 16

18 17 30 29

HYDRAULIC UNITS

CYLINDERS

IV-107

TB175W

Assembly
Clevis

1. Using installation jig (B), pressure fit the bushing

(44) in the piston rod and tube.

2. Using a setting tool, install the dust seal.

Rod Cover

1. Using an installation jig (A), pressure fit the

bushing.
• Hydraulic oil should be applied to the inside

surface of the rod cover before assembly.

• After installation, make sure there are no level

differences with the bushing.

2. Install the O-rings (15), (16) and the backup rings

(20).

3. Using setting tool (G), pressure fit the dust seal

(22).

4. Install the rod packing (21).

5. Install the buffer ring (19).

<Swing>
• Attach the seal ring (25), bend the buffer ring

(26) into a U shape with your fingers, then set
it in the groove. Make sure it is bent with a
radius of 6mm or greater to prevent wrinkles.

• Be sure to install it in the proper direction.

6. Install the snap ring (23).

W2D406

15 19 24

20 16

W2D407E

(PROJECTION)

(SLIT)

< Swing >

HYDRAULIC UNITS

CYLINDERS

IV-108

TB175W

7. Install the collar (30) and the cushion seals (29).

8. Install the O-ring (17) and the backup rings (18).

Piston

1. Install the O-ring (27) on the piston.

2. Cover the piston with the sliding jig (C), then,

using the fitting jig (D), insert the slipper ring (28)
rapidly.

3. Since the slipper ring (28) is extended when it is

installed, correct it using the corrective jig (E).

4. Install the wear ring (13).

• Spread the wear ring at the cut portion the

minimum amount necessary, installing it on
the piston from the shaft direction.

Piston Rod Assembly

1. Fasten the piston rod so that it is flat and install the

rod cover.
• Cover the piston rod thread with tape, etc., to

protect the seals from being scratched.

2. Install the cushion bearing (10).

a. Install the cushion seal (12).

• Set the side with the slits facing the screw

side.

b. Install the cushion bearing (10).

• Be sure to set with the flat side (A) in the

proper direction.

c. Install the stopper (11) on the piston rod, and

move the cushion bearing (10).

d. Install the snap ring (9).

W2D408

18 17

30 29

HYDRAULIC UNITS

CYLINDERS

IV-109

TB175W

3. Install the cushion seal (8) and cushion bearing

(7).
• Set the side of the cushion seal with the slits

facing the screw side.

• Be sure to set with the flat side (A) of the

cushion seal in the proper direction.

4. Install the piston.

a. Install the piston (6).
b. Install the piston nut (4) and tighten it.

Piston nut: Refer to the table below.

c. Insert the steel ball (3).
d. Tighten the set screw (2) and caulk it at two

places with a punch.

Set screw: Refer to the table below.

Piston Nut, Set Screw

Cylinder Assembly

1. Fasten the tube in a horizontal position, then

insert the piston rod assembly in the tube.
• During insertion, align the center of the piston

rod with the center of the tube, inserting it
straight so the seals will not be scratched.

2. Tighten the rod cover.

• Apply Three Bond #1901 or the equivalent to

the rod cover tread.

Rod cover

Unit: N·m

3. Bend the lock rib on the tube down in a notch of

the rod cover to lock it.

Boom

Arm

Bucket

Boom Adjustment

Swing

1060

647

490

530

1060

Place

Piston Nut

Set Screw

Boom

Arm

Bucket

Boom Adjustment

Swing

3500

3100

1540

1470

4410

56.9

31.5

56.9

Unit: N·m

HYDRAULIC UNITS

CYLINDERS

IV-110

TB175W

Measuring the Bend

a. Support the portion of the rod with the same

diameter at both ends on V-blocks.

b. Set a dial gauge at the center between the two

blocks.

c. Rotate the rod and take a reading of the maximum

and minimum runout indicated by the dial gauge.

INSPECTION AND ADJUSTMENT

Inspection after Disassembly

Clean each part thoroughly with cleaning oil, then
carry out the following checks. When a cylinder has
been disassembled, replace all the seals with new
ones.

Piston Rod

• Replace the rod if there are cracks.
• If the threads are damaged, repair them or replace

it.

• If the plating layer of the plated portion is broken,

rusted or scratched, replace it.

• If the rod is bent more than the limit of 1 mm in 1

m, replace it. (Measure by the method shown in the
figure at right.
If the bending of the rod is within the above limit,
yet is bent a lot in a small distance so that it won’t
move smoothly, replace the rod if it makes a
squeaking sound in the operation test after reas-
sembly or if it catches during movement.

• If the inner diameter of the clevis bushing is worn,

replace the bushing.

Tube

• If there are cracks in the welded portion, replace it.
• Replace the tube if the inside surface is scratched

or if it leaks hydraulic oil.

• If the inner diameter of the clevis bushing is worn,

replace the bushing.

Rod Cover

• If the bushing inner diameter is worn and the

clearance with the piston rod is greater than 0.25
mm, replace the bushing.

• If the inside surface of the bushing is scratched, and

the scratches are deeper than the depth of the
coating layer, replace the bushing.

HYDRAULIC UNITS

CYLINDERS

IV-111

TB175W

Inspection after Assembly
No Load Operation Test

1. Place the cylinder in a horizontal position with no

load.

2. Apply gentle pressure alternately to the ports at

both ends, operating the piston rod 5 or 6 times.

3. Make sure there is no abnormality in the operat-

ing condition.

Leak Test

External Leakage
1. Apply test pressure for 3 minutes each to the

retraction side and the extension side.

2. Make sure there are no abnormalities such as

external leakage or permanent deformation, etc.
in the rod seal, the rod cover mount, or in any
welded portion.

Internal Leakage
1. Disconnect the extension side hose.
2. Apply test pressure to the retraction side for 3

minutes.

3. Measure the amount of oil that has leaked from

the extension side.
• The amount of leakage should be 1 cm

/ 3min

or less.

Bleeding Air from the Hydraulic Cylinder

Bleed the air out of the cylinder when the cylinder is
removed or when the hydraulic piping, etc. is discon-
nected.
1. Start the engine and let it idle for approximately

5 minutes.

2. With the engine running at slow speed, extend

and retract the cylinder 4 or 5 times.
• Move the piston rod to a position 100 mm

before the end of the stroke, being careful not
to apply any relief at all.

3. With the engine at top speed, repeat the operation

in (2), then with the engine running at slow speed,
move the piston rod to the stroke end and apply
relief.

HYDRAULIC UNITS

CYLINDERS

IV-112

TB175W

• Remove the foreign matter.

• Replace the affected parts.

TROUBLESHOOTING

Symptom

Probable Causes

Remedy

Oil leaks from piston rod
sliding surface (an oil ring
forms on the piston and
this enlarges and drips off).

• Foreign matter is caught in the inner

diameter portion of the rod packing,
backup ring or dust seal.

• The inner diameter lip of the rod packing,

backup ring or dust seal is damaged or
abnormal.

• Piston rod sliding surface is scratched.

• The hardened chrome plating is separat-

ing from the piston rod.

• Smooth the sliding surface with an oil

stone (1.6 S or lower)

• If it leaks after the sliding surface has

been smoothed, replace the rod pack-
ing and other seals.

• If it leaks after the seals have been

replaced, replace the piston rod.

• Repair the hardened chrome plating.

• O-ring is damaged.
• Backup ring is damaged.

• Replace the affected parts.
• Replace the affected parts.

Oil leaks from the outer
circumference of the rod
cover.

Oil leaks from welded por-
tion.

• The tube’s welds are damaged.

• Replace the affected parts.

Cylinder natural drop (this
is the maximum amount
of movement of the piston
in 10 minutes when a static
weight corresponding to
the maximum use pressure
multiplied by the
cylinder’s surface area) is
0.5 mm or greater.

• Foreign matter is caught in the wear ring

sliding surface.

• The sliding surface of the wear ring is

scratched or abnormal.

• The piston packing sliding surface is

scratched.

• The O-ring is damaged.

• Remove the foreign matter.

• Replace the affected parts.

Takeuchi Hydraulic Excavator TB175W (S/N 17540001~). WORKSHOP MANUAL - page 15