PDF Shop Manual KOMATSU WB70A-1 Backhoe Loader - 3 MB
The Komatsu WB70A-1 Backhoe Loader Shop Manual is the ultimate guide for service and repair.
This manual contains in-depth instructions for testing, adjusting, disassembly, and assembly of the machine.
It is filled with diagrams, schematics, and specifications to assist technicians in performing accurate and efficient repairs.
This is an indispensable tool for any professional mechanic maintaining this equipment.
PDF Viewer
Viewer loads when you scroll here
SHARE THIS MANUAL
Download the PDF Manual
PDF viewer loading area
Text Preview from This Manual
The text below was extracted from the visible preview pages to help you confirm the manual contents before download.
--- Page 3 ---
HOISTING INSTRUCTIONS
HOISTING INSTRUCTIONS
ing, and a serious accident can result.
Heavy parts (25 kg or more) must be lifted Hooks have maximum strenght at the middle
with a hoist etc. In the Disassembly and As- portion.
sembly section, every part weighing 25 kg or
more is clearly indicated with the symbol
1. If a part cannot be smoothly removed from the
machine by hoisting, the following checks should
be made:
. Check for removal of all bolts fastening the part
to the relative parts.
. Check for any part causing interference with
the part to be removed. 3) Do not sling a heavy load with one rope alone,
but sling with two or more ropes symmetrically
wound on to the load.
2. Wire ropes Slinging with one rope may cause turning of
1) Use adequate ropes depending on the weight the load during hoisting, untwisting of the ro-
of parts to be hoisted, referring to the table be- pe, or slipping of the rope from its original
low: winding position on the load, which can cau-
se dangerous accidents.
WIRE ROPES
(Standard «S» or «Z» twist ropes
without galvanizing)
4) Do not sling a heavy load with ropes forming a
Rope diameter (mm) Allowable load (tons) wide hanging angle from the hook.
When hoisting a load with two or more ropes,
10 1.0 the force subjected to each rope will increase
with the hanging angles.
11.2 1.4 The table below shows the variation of allowa-
ble load (kg) when hoisting is made with two ro-
12.5 1.6 pes, each of which is allowed to sling up to
1000 kg vertically, at various handing angles.
14 2.2 When two ropes sling a load vertically, up to
16 2.8 2000 kg of total weight can be suspended.
This weight becomes 1000 kg when two ropes
18 3.6 make a 120ë hanging angle.
On the other hand, two ropes are subjected to
20 4.4 an excessive force as large as 4000 kg if they
sling a 2000 kg load at a lifting angle of 150ë.
22.4 5.6
30 10.0
40 18.0
50 28.0
60 40.0
The allowable load value is estimated to be
one-sixth or one-seventh of the breaking
strength of the rope used.
2) Sling wire ropes from the middle portion of the
hook. Slinging near the edge of the hook may
cause the rope to slip off the hook during hoist-
00-7
--- Page 4 ---
POWER TRAIN
REDUCTION RATIO
Reduction gear
Differential Planetary Total axle Total
(Transmission)
High speed 1.093 18.47
3.22 5.25 16.915
Low speed 4.06 68.6
Front
Fronteofmacchina
machine
6 Z=29 Z=9
Z=51
Z=12
Z=19
4
Z=73
Z=18
8
Z=43 Z=47
2
3 5
1
9
Z=29 Z=9
Z=19
Z=12
Z=51
7
D0400766
1. Engine (Diesel) 6. Front axle
2. Hydraulic pump 7. Rear axle
3. Travel motor 8. Front wheels
4. Transmission 9. Rear wheels
5. Drive shaft
10-3
--- Page 5 ---
HYDROSTATIC TRANSMISSION OPERATION
. Pump shaft (1), (which drags cylinder barrel) is ro- . This is the «closed circuit» principle which, theoreti-
tates by the engine. cally, utilises once again the same oil quantity.
. Moving the positioning piston (2) the swash plate is NOTE - Moving the positioning piston in the other di-
shifted from neutral position; an angle is fixed be- rection, it will create the reversal direction of engine
tween pistons and swash plate (on which pistons rotation.
are constrained); this angle will create a volume dif- . Oil leakages between moving parts, cause, during
ference in one side smaller and in the other side machine's life, the emptying of closed circuit; this
bigger. In this way it is created an oil pressure de- trouble is solved applying a gear pump (3) named
livery area (hydraulic power) through hydraulic mo- boosting pump, which sucks oil from the hydraulic
tor (pipe A on diagram) and a suction area from hy- tank and introducing it into the closed circuit keep-
draulic motor (pipe B on diagram). ing inside constant pressure, checked by a fixed
. The oil sent from pump to motor (pipe A), pressing setting main relief valve (4).
on pistons, will move pistons and consequently the . Part of pressurised oil of the boosting circuit is used
output shaft (14), transforming «hydraulic power» for positioning piston (2) operation which allows the
into «mechanical power». stepless variable inclination of the swash plate and
. The oil transferring power is returned through pipe therefore the hydraulic motor speed.
(B) to hydraulic pump's suction port to be reused. . All the system is protected from pressure peaks
(and therefore from overloads) by safety valves (7).
7 8 B
PUMP
POMPA MOTOR
6 MOTORE
14
1
Swash
3
Piatto Cylinder
Blocco
plate
oscillante barrel
cilindri 7 4
10 13
12
11
A
9
2 5
D0400773
10-13
--- Page 6 ---
TRAVEL MOTOR
1
3
2
a
c
X b
View
Vista X
X
D0400695
4 d
a. A Port - From hydrostatic transmission pump 1. EV8 Additional piloting device
(B Port) 2. Automatic variable displacement device
b. T1 Port - From hydrostatic transmission pump 3. EV9 Detection of travel direction device
(T1 Port) 4. Oil exchange valve
c. B Port - From hydrostatic transmission pump
(A Port)
d. T Port - To oil radiator (C1 Port)
10-23
--- Page 7 ---
3-SPOOL CONTROL VALVE
b 1 c A B C d e
a
l
i h A B C g f
2 3 2 6 7
5 5 5
2 4 2 4 4
Section
Sezione A
A -- A
A Section
SezioneBB -- B
B SectionCC- -CC
Sezione D0400690
a. T2 Port - From priority valve (EF Port) and from 1. Main relief valve
backhoe control valve (P Port) 2. Safety-suction valve
b. P Port - From pump P3 (P Port) 3. Spool (Optional attachments)
c. B1 Port - To auxiliary attachments (L.H. side) 4. Spool return spring
d. B2 Port - To dump cylinder (Bottom side) 5. Check valve
e. B3 Port - To lift cylinder (Bottom side) 6. Spool (Bucket)
f. A3 Port - To lift cylinder (Head side) 7. Spool (Lift arm)
g. A2 Port - To dump cylinder (Head side)
h. A1 Port - To auxiliary attachments (R.H. side)
i. T Port - To hydraulic oil tank
l. T1 Port - From oil radiator (C2 Port)
10-35
--- Page 8 ---
BRAKE PUMP
3
4
1 2 5 6 7 8
17 16 15 14 13 12 11 10 9
D0400699
1. Pump body SPECIFICATIONS:
2. Main piston Stroke: 36 mm
3. Oil brake tank Displacement: 15 cc
4. Union Max. pressure: 150 bar
5. Oil seal
6. Piston
7. Detaching valve spring
8. Pump spring
9. Plug
10. Seal
11. Pin
12. Seal
13. Seal
14. Seal
15. Ball
16. Spring
17. Seal
10-45
--- Page 9 ---
BACKHOE CONTROL LEVER
1
4
3 5
2 8
7 6
1
10 3
12
9
11
2
4
6
5
CONTROL LEVER POSITION
1 Arm out
2 Arm in
3 Bucket dump D0400772
4 Bucket curl
5 Boom lower
6 Boom raise
7 Boom R.H. swing 1 - R.H. work equipment control lever
8 Boom L.H. swing 2 - R.H. outrigger control lever
9 R.H. outrigger lower 3 - L.H. work equipment control lever
10 R.H. outrigger raise 4 - L.H. outrigger control lever
11 L.H. outrigger lower 5 - Backframe locking lever
12 L.H. outrigger raise 6 - Backhoe locking lever
10-55
--- Page 10 ---
. FOR MACHINE
Machine model WB70A-1
Classi- Check item Test conditions Unit Standard Permissible
fication value value
D0401011
Boom swing Max. 15 Max. 20
(each side)
. Oil temperature: 55 ± 65ëC
. Backhoe balanced on the guides, bucket
in transport condition.
. Arm and bucket cylinder in. Put the buc-
ket link pin at 1 meter from ground and
swing at end of boom stroke in one of
the two direction.
. Move the machine on a chute of 15ë and
Hydraulic drift working equipment
apply the parking brake.
. Stop the engine and, after 1 minute,
check the cylinder feed back opposite
to the boom every 5 min. for a total of
15 minutes.
Backhoe
H Make the test for each swing direction.
mm
D0401012
Outriggers Max. 20 Max. 30
. Oil temperature: 55 ± 65ëC
. By pass the safety valves.
. Balanced backhoe.
. Boom and arm cylinders in, bucket cylin-
der out
. Outriggers at maximum extension.
. Engine stopped.
. Check the frame lowering for each side
every 5 min. for a total of 15 minutes
20-8
--- Page 11 ---
TESTING AND ADJUSTMENT ADJUSTING VALVE CLEARANCE
ADJUSTING VALVE CLEARANCE
H Adjust clearance between valves and rocker levers as 1
follows:
Unit: mm
Intake valve Exhaust valve
At cold
engine
0.20 0.20
H Firing order: 1-3-4-2-1.....
H Normal rotation sense: counterclockwise from flyw-
heel
. Adjusting procedure F0401182
1 - Remove valves cover (1).
2 - Rotate crankshaft in normal direction as long as
cylinder piston to be checked is at compression 3
Top Dead Center. (PMS).
2
H In this position intake and exhaust valves are clo-
sed.
3 - Loose lock nut (2) and unscrew tappet (3) of about
1 turn.
4
H Check that valve insert (4) is laying flat on val-
ve stem and that it is not worn askew.
SI
YES NO
NO
1 - If valve inserts (4) are damaged, replaced
them with new ones.
2 - Make sure that inserts feet and lay flat on D0400882 4
valve stem.
4 - Connect A1 feeler gauge between insert and roc-
ker lever to adjust; rotate the tappet (3) until tou-
ching A1 feeler gauge. 3 2
Tight tappet (3) with lock nut (2).
H After tightening the lock nut, check the clea- A1
rance again.
5 - Adjust with same procedures second cylinder val-
ve and repeat same operation for the other cylin-
ders, according to the firing order.
D0400893
. Cover valves installation
1 7
1 - Check condition of cover valves (1), gasket (5), O-
Rings (6) and lock nuts (7); clean carefully contact 6
surface on cylinder head.
2 - Install valves cover (1), fit O-Rings (6) and lock
nuts (7).
Cover lock nut: 25w3 Nm
5
D0400891
20-18
--- Page 12 ---
TESTING AND ADJUSTMENT AIR BLEEDING - RELEASING RESIDUAL PRESSURE
6. Releasing residual pressure from the
circuits
1 - Put work attachments on level ground, stop the engi-
ne and remove tank plug.
2 - Move all control levers in all directions to release
completely cylinders and main circuit remain pressu-
re.
3 - Loosen slowly oil filler tank to remove remain pressu-
re.
7. Air bleeding from braking circuit
H Above operation is to be carried out every time main-
tenance is made on braking circuit to remove or repla- 1
MAX
ce a component, or when air entered into the circuit.
H Machine must be stopped with attachments on level MIN.
ground.
1 - Make sure that oil in brake system tank (1) is at maxi-
mum level.
F0401201
2 - Remove safety plugs and applied to bleeding screws
(2) a vinyl hose (3) to catch oil.
3 - Push brake pedal to bottom and, keeping it pushed,
loosen bleeding screw (2) of one of two braking units
until the pedal reaches end of its stroke.
2
4 - Keeping pedal at the end stroke, tighten bleeding
screw (2).
5 - Release braking unit pedal during air bleeding, wait
for few seconds and repeat above operations until
from bleeding screw, oil flows out without air bubbles. 3
6 - Repeat same operations for the other braking unit. F0401202
H Check frequently the oil level in the tank and carry out
filling every time level approaches to minimum.
H After air bleeding apply on screws (2) safety plugs.
20-28
--- Page 13 ---
TESTING AND ADJUSTING
TESTING AND ADJUSTMENT HYDROSTATIC TRANSMISSION
4. Testing and setting of valve pressure cut (1)
1 - Remove port plugs (MA - MB) and connect two gau-
ges E1 (600 bar).
2 - Start the engine and select 2nd forward speed.
3 - Brake firmly the wheels using brake pedal and, kee-
ping the brake pedal pushed accelerate gradually un- 1
til reaching high idling speed.
2
F0401208
4 - Check on gauge (MB) that pressure reaches normal
value.
H Cutting pressure: 440 10 bar E1 E1
H If pressure is not within tolerance limit, set valve
pressure cut (1). MA
MB
Setting
1 - Remove safety plug (2). D0400898
2 - Loosen nut (3).
3 - Adjust pressure by adjusting screw (4).
. To INCREASE pressure, rotate in CLOCKWISE 2
direction. 4
. To DECREASE pressure, rotate in COUNTER-
3
CLOCKWISE direction.
4 - Lock the position with nut (3).
Nut: 22 Nm 1
5 - Return engine at low idling speed, apply reverse
speed and check also the second port.
6 - Apply safety plug (2) against not authorised tampe-
rings.
H If in spite of valve cut pressure adjusting, pressure
does not reach normal value in both ports:
1 - Check boosting pressure setting (see paragraph 2).
2 - Check pump setting starting point adjustment
(see paragraph 3).
3 - Remove the port safety valve where failure is relie-
ved and proceed to overhaul at bench or to repla-
cement.
D0400876
20-38
--- Page 14 ---
TESTING AND ADJUSTMENT TESTING BRAKE SYSTEM
3 - Connect tool H1 between brake pump hose (1) and
eye union (5) of one of the two brake units. 1
4 - Connect to tool H1 pressure port a gauge E3 (250
bar) and open the exclusion valve (6).
E3
5 - Operate brake pump to feed pressure into the circuit
6
to maximum pressure of 150w10 bar.
6 - Keeping pressure, close valve (6) to keep in pressure
the brake unit to test.
7 - Release the brake pedal and check for 2 minutes the
H1
pressure indicated by gauge E3.
F0401224
H If pressure value has a negative change, it means that
at least one of steering piston is defective.
H If pressure value keeps steady, defect concerns the
other steering unit. 5
1 - A further confirmation about leak of one or more
steering pistons, can be also shown by oil level
increase in the axle central housing.
2 - If there are level increases, and therefore oil mi-
xing due to steering piston leaks, replace all
seals among axle section and replace lubricant
completely.
8 - Repeat, as confirmation, test for the other brake unit 1
using the same procedure.
F0401225
9 - Reset brake circuit with disassembled parts.
After testing and possible repairs, bleed air from bra-
ke units (see «AIR BLEEDING OF BRAKE CIRCUIT»).
20-48
--- Page 15 ---
DISASSEMBLY AND ASSEMBLY
HOW TO READ THE MANUAL. . . .. . . . .. . . . . .. . . . .. . . 3 PISTON PUMP AND STEERING PUMP
PRECAUTIONS TO BE TAKEN WHILE Removal and installation. . . . .. . . . . .. . . . . .. . . . .. . . . 34
WORKING . . . . .. . . . .. . . . . .. . . . .. . . . . .. . . . .. . . . . .. . . . .. . . 4 Disassembly . .. . . . .. . . . . .. . . . .. . . . . .. . . . . .. . . . .. . . . 35
SPECIAL TOOLS Assembly . . . . . .. . . . .. . . . . .. . . . .. . . . . .. . . . . .. . . . .. . . . 41
(For machine). .. . . . .. . . . . .. . . . .. . . . . .. . . . .. . . . . .. . . . .. . . 5 ENGINE-PUMP COUPLING JOINT
SPECIAL TOOLS Removal and installation. . . . .. . . . . .. . . . . .. . . . .. . . . 47
(For backhoe). .. . . . .. . . . . .. . . . .. . . . . .. . . . .. . . . . .. . . . .. . . 7 TRAVEL MOTOR
STARTER MOTOR Removal and installation. . . . .. . . . . .. . . . . .. . . . .. . . . 48
Removal and installation .. . . . . .. . . . .. . . . . .. . . . .. . . 9 Disassembly . .. . . . .. . . . . .. . . . .. . . . . .. . . . . .. . . . .. . . . 49
ALTERNATOR Assembly . . . . . .. . . . .. . . . . .. . . . .. . . . . .. . . . . .. . . . .. . . . 53
Removal and installation .. . . . . .. . . . .. . . . . .. . . . .. . 10 STEERING PUMP
INJECTION PUMP Removal and installation. . . . .. . . . . .. . . . . .. . . . .. . . . 58
Removal. . . .. . . . .. . . . . .. . . . .. . . . . .. . . . .. . . . . .. . . . .. . 11 STEERING GEAR PUMP
Installation .. . . . .. . . . . .. . . . .. . . . . .. . . . .. . . . . .. . . . .. . 13 Disassembly . .. . . . .. . . . . .. . . . .. . . . . .. . . . . .. . . . .. . . . 59
NOZZLE HOLDER Assembly . . . . . .. . . . .. . . . . .. . . . .. . . . . .. . . . . .. . . . .. . . . 61
Removal and installation .. . . . . .. . . . .. . . . . .. . . . .. . 15 WORK EQUIPMENT PUMP
CYLINDER HEAD Removal and installation. . . . .. . . . . .. . . . . .. . . . .. . . . 63
Removal. . . .. . . . .. . . . . .. . . . .. . . . . .. . . . .. . . . . .. . . . .. . 16 BRAKE PUMP
Installation .. . . . .. . . . . .. . . . .. . . . . .. . . . .. . . . . .. . . . .. . 17 Removal and installation. . . . .. . . . . .. . . . . .. . . . .. . . . 64
RADIATOR - OIL COOLER UNIT TRANSMISSION-REVERSE, DIRECTION
Removal. . . .. . . . .. . . . . .. . . . .. . . . . .. . . . .. . . . . .. . . . .. . 18 INDICATOR AND HEADLIGHT DIPPER BEAM
Installation .. . . . .. . . . . .. . . . .. . . . . .. . . . .. . . . . .. . . . .. . 19 CONTROL GROUP
MUFFLER Removal and installation. . . . .. . . . . .. . . . . .. . . . .. . . . 65
Removal and installation .. . . . . .. . . . .. . . . . .. . . . .. . 20 STEERING UNIT
EXHAUST PIPE Removal and installation. . . . .. . . . . .. . . . . .. . . . .. . . . 66
Removal and installation .. . . . . .. . . . .. . . . . .. . . . .. . 20 Disassembly . .. . . . .. . . . . .. . . . .. . . . . .. . . . . .. . . . .. . . . 67
SEAT AND ENGINE HOOD Assembly . . . . . .. . . . .. . . . . .. . . . .. . . . . .. . . . . .. . . . .. . . . 73
Removal and installation .. . . . . .. . . . .. . . . . .. . . . .. . 21 PRIORITY VALVE
SIDE COVER Removal and installation. . . . .. . . . . .. . . . . .. . . . .. . . . 83
Removal and installation .. . . . . .. . . . .. . . . . .. . . . .. . 22 Disassembly and assembly. .. . . . . .. . . . . .. . . . .. . . . 84
HEATING RADIATOR FRONT EQUIPMENT CONTROL VALVE
Removal and installation .. . . . . .. . . . .. . . . . .. . . . .. . 23 Removal and installation. . . . .. . . . . .. . . . . .. . . . .. . . . 85
CAB FRONT AXLE
Removal. . . .. . . . .. . . . . .. . . . .. . . . . .. . . . .. . . . . .. . . . .. . 24 Removal .. . . . . .. . . . .. . . . . .. . . . .. . . . . .. . . . . .. . . . .. . . . 86
Installation .. . . . .. . . . . .. . . . .. . . . . .. . . . .. . . . . .. . . . .. . 27 Installation. . . . .. . . . .. . . . . .. . . . .. . . . . .. . . . . .. . . . .. . . . 87
FUEL TANK REAR AXLE
Removal and installation .. . . . . .. . . . .. . . . . .. . . . .. . 28 Removal .. . . . . .. . . . .. . . . . .. . . . .. . . . . .. . . . . .. . . . .. . . . 88
Installation. . . . .. . . . .. . . . . .. . . . .. . . . . .. . . . . .. . . . .. . . . 89
HYDRAULIC OIL TANK