10.

DUMP SYSTEM

2-2. MAIN SPECIFICATIONS

19TON (24TON)

Model M6D8F(N7D9F), (N7DVF, N7DDF)

Max. loading capacity(ton) 19 (24)

Hoist type FC 141-4(FC 162-4)(FE162-4), Telescopic cylinder

Pump type Gear pump 087L

Pump standard speed(rpm) 350 ~ 3,000

Delivery(cc/rev) 86

Normal operating pressure

Max. 280
(kg/cm2)

Stage 1st 2nd 3rd 4th Total

141 120 99 78
Effective diameter(mm) (162)(162) (141)(141) (120)(120) (99)(99) -

1,130 1,150 1,180 1,180 4,640

Telescopic cylinder Stroke(mm) (1,204)(1,268) (1,224)(1,287)(1,254)(1,317) (1,254)(1,273) (4,936)(5,145)
18 13 9 6 6
Oil displacement(L) (25)(26) (19)(20) (14)(15) (10)(10) (68)(71)
Operating pressure Dumping capacity
170 (ton) 28ton (45ton)(43ton)
(kg/cm2)

Tipping valve type PT-1220-170

Cylinder oil ISO VG 32

Dumping Max. angle degrees 50°

Oil tank capacity(L) 85 (91) Operation capacity(L) 67 (73)

Air control type 147-50-150H

48
 10. DUMP SYSTEM

2-3. HYDRAULIC AND PNEUMATIC DIAGRAM

1. Oil tank
2. Pump
C 3. Dumping valve
4. Cylinder
5. Control valve
6. Air control
7. Return line filter
4
5
Tip Lower

3
T
P
M 6
7 2
1
Hydralic lines
Pneumatic lines

DU1031

- Actuate the P.T.O. and dump control lever installed by the driver's seat to raise, lower, or stop the
deck at the desired position.
- The dump system is of telescopic type upgraded in manipulability, safety, and performance and con-
sists of the deck, hydraulic system and other ancillary devices.
- As the ascending position of the deck is in the front, no high power for ascent is needed.
- As the dump system is so designed that the dump load is distributed evenly over the vehicle, it guar-
antees high safety and long life of the vehicle.
- Power can be transferred from the P.T.O. attached to the transmission and it is easy to supply or cut
off power by actuating it with compressed air.
- The stabilizer functions to prevent rolling of the deck to assure safety in operation.

49
10. DUMP SYSTEM

2-4. TELESCOPIC CYLINDER SYSTEM

G: Grease to be applied
A: To be replaced at disassembly

Hose
Oil tank Air control for
P.T.O. and valve

Telescopic
cylinder

Cylinder
bracket
P.T.O.
Control valve

FC Knock-off

Stop valve

Gear pump G, A

Suction hose

G, A
P.T.O.

DU1041

50
 10. DUMP SYSTEM

2-5. HOW TO OPERATE

• The P.T.O. pump and tipping valve must be controlled within the cab. (The gearshift lever must be
placed in the NEUTRAL position.)
• P.T.O. control
This control device has the two positions of IN GEAR and OUT OF GEAR. If the tipping gear is not
in an operating condition or the engine remains stationary, the switch must be in OUT OF GEAR
position. When the actuation of P.T.O. by air pressure causes the P.T.O. to be engaged, the warning
lamp next the switch lights up.
• Tipping gear control
This control device has the three positions of TIP, HOLD, and LOWER. The position for HOLD is
neutral. When the tipping gear is not in operation, the lever must be placed in the NEUTRAL position.

2-5-a. GUIDE FOR OPERATION

1. Check the oil level(with the tipping gear placed in LOWER position and at about 5cm from the tank
top surface) before operating the hydraulic tipping gear.
All the bearings and pivots must be coated with lubricant. The P.T.O. control lever must be placed in
OUT OF GEAR position.
2. Procedure for engaging the P.T.O.
Start the engine, and raise the speed until pressure in the air system reaches 6 bar(87 PSI). The
tipping valve control lever must be in NEUTRAL position. Place the gearbox select lever also in the
NEUTRAL position and depress the clutch, and after the lapse of about 4 seconds, turn on the P.T.O.
switch and wait until the warning lamp lights up.
3. When raising the deck
Move the ram control lever to the TIP position. Oil under pressure flows to the hydraulic ram, causing
it to extend all the way, and the deck will be pushed up to one side. It may be possible to raise the
engine RPM in order to make tipping movement faster(Maximum engine speed: 1,750 rpm). When
the deck reaches the maximum height or maximum angle when ascending, place the lever back in
the HOLD position.
4. When disengaging the P.T.O.
Depress the clutch and disengage the P.T.O., then wait until the warning lamp goes out and release
the clutch.
5. Do not run the vehicle with the P.T.O. engaged.
6. When lowering the deck
With the ram lever in LOWER position, when the deck reaches the chassis frame, move the ram
lever to HOLD position. The multi-stage lowering feature provided by the valve allows the experi-
enced operator to lower the deck smoothly when handling heavy materials.
In addition, the valve is useful to such operators who continue to operate the vehicle in order to
spread stockpile or materials.

51
10. DUMP SYSTEM

7. When lowering the control screw

The set screw installed in the upper of the tipping valve allow you to control the stroke of pneumatic
actuator, through which the opening of the return port on the valve is controlled properly.
To reduce the descending speed, tighten this screw until the desired speed is obtained and then secure
it with nuts.
8. Suspension of tipping operation
Even if the pump is in operation, relocate the ram control from TIP to HOLD position.
The control lever must return to HOLD position again immediately after it reaches the end of tipper
stroke or the lower position. Avoid running the vehicle with the deck raised (slightly) or lowering sud-
denly the deck loaded half with materials.
The lowering movement by the control shows proportion relationships. When lowering the deck loaded
with materials, move it cautiously and gently from HOLD to LOWER position and then replace it in
HOLD position if the deck reaches the desired tipping angle.

52
 10. DUMP SYSTEM

2-5-b. P.T.O. AND VALVE OPERATING SYSTEM

Air control for P.T.O. and valve

Telescopic cylinder
Tipping
valve P.T.O

FC knock-off

Gear pump

DU1050

1. P.T.O. constitutes an integral part of the gear box. When switching the P.T.O. to “INSIDE” or “OUT-
SIDE”, always separate the clutch.
2. If you did not separate the clutch or wait a few seconds until the gear stops, gear teeth may damage
the clutch.
3. P.T.O. works using air pressure from the air tank, which is obtained by actuating the P.T.O. switch.
The power for it is supplied by the hydraulic pump.
4. If the control lever inside the cab is placed in UP/DOWN position so that air pressure from the air tack
actuates the valve spool, the hydraulic pressure generated in the pump is supplied for the cylinder.
5. If you did not separate the clutch or wait a few seconds until the gear stops, gear teeth may damage
the clutch.
6. For a vehicle mounted with a P.T.O. which is actuated by compressed air, if it is necessary to run the
vehicle at idle for an extended period of time(example: all night long), be sure to shut off the P.T.O.
drive.

53
10. DUMP SYSTEM

2-6. TELESCOPIC CYLINDER ASSEMBLY

A: To be replaced at disassembly
B: Hydraulic oil to be applied

Telescopic cylinder

Lifting bracket

A
Bracket

Adapter

B Piston B B Cylinder
rod cover

Bottom
plate
A
Locking
Plate

DU1060

54
 10. DUMP SYSTEM

2-7. GEAR PUMP AND P.T.O. DISASSEMBLY

Elbow

Housing Hose pillar

Seal
Seal
Adapter

Gear pump assembly

Seal

Dowel pin
Bearing
Thrust plate Seal
Driven gear

Thrust plate
Bearing
Pin Washer
Washer/nut Cover Circlip
Washer/bolt

Quill shaft Stud

Spacer
Gasket
Coupling

Washer/nut

Gasket
stud bolt

DU1070

55
10. DUMP SYSTEM

2-8. CONSTRUCTION OF EACH COMPONENT

2-8-a. TELESCOPIC CYLINDER ASSEMBLY

Cylinder cover

Lifting bracket

Chassis bracket

DU1081

• The telescopic cylinder is separated from the oil tank and mounted in front of the sub-frame and
deck. It is supplied with compressed oil by the hydraulic pressure pump to actuate the deck to as-
cend or descend.

2-8-b. STABILIZE

G: Greasing point

G: Greasing point

G
G

GG

G
G
DU1091

• The upper portion is mounted on the middle part of the deck, and the lower portion is mounted on the
sub-frame. The stabilizer rises or comes down according to the hydraulic cylinder's operation and
prevents rolling or inclining of the deck during ascent or descent of the deck.

56
 10. DUMP SYSTEM

2-8-c. AUTOMATIC RELEASING DEVICE FOR TAIL GATE

Slide lever
assembly
Bracket-slide lever

Turn buckle

Return spring

Rear gate hook asm

DU1101

• This is a device designed to open or shut the rear gate automatically at ascent or descent of the deck
by using the body lock installed on the sub-frame. When the rear gate rises, the hook is released by
the spring force, and when it comes down, the roller get in contact with the bracket of the sub-frame
so that the hinge and hook installed on the tail gate are coupled with each other.

57
10. DUMP SYSTEM

2-8-d. AIR CONTROL

Air control P.T.O./valve with automatic disengagement

On the air control the following connections are indicated

IN = Air inlet
Washer EX = Air exhaust
TIP = Tipping position
LOW = Lowering position
P.T.O.= Power take-off

Coupling for air control

DU1111

1. The air control for P.T.O./valve with automatic P.T.O. disengagement is a three way operated, vari-
able air control.(P.T.O., tip and lower operation)
2. When used with a compatible tipping valve with proportional lowering, the speed of descet of the
body can be regulated by the proportional movement of the air control lever.
3. The air control includes an electrical indicator to show P.T.O. engagement.
4. Hyva air controls are easy to mount in the cabin.
5. The functions of Hyva air controls are clearly indicated with symbols.

58
 10. DUMP SYSTEM

2-8-e. TIPPING VALVE(WORKING PRESSURE)

1. Pump - connection(P)
2A. Return to tank - connection two possibilities(T)
2B. Sub. Return to tank connection
3. cylinder connection
4. pneumatic connection of air control-tipping
5. pneumatic connection of air control-lower
6. regulator for adjustment of lowering speed.
7. pressure gauge point
8 8. cartridge
1

29
2
4
5
2A

2B
3

7
126

DU1121

Type PT 1220-170 Max. peak pressure 350 bar

Hydraulic connections G 1" Oil types Mineral oil(DIN51524/51525)

Pneumatic connections G 1/8" Temperature range -25°C / +80°C

Max. working pressure 170 bar Pneum. pilot pressure 6-10 bar

Caution
a. mount the valve according to the HYVA mounting instructions.
b. Use the correct washers and adapters in the ports to prevent housing deformation.
Do not use adapters with tapered threads.
c. To further prevent deformation of the valve housing. the mounting plate surface or block must be completely flat.
d. To prevent corrosion of the pneumatic parts, the pressurised air must be free of moisture.
e. Do not weld to the valve.
f. Max. torque for bolts to mount the valve is 15 Nm.
g. If the tipping valve disassemble, replace the seal and O-ring, all parts must be reas sembled after cleaning.

59
10. DUMP SYSTEM

2-8-f. ADJUSTING OF AIR KNOCK-OFF

Bolt
Nut

Shaft Filter

Bearing bush Base plate

Washer Base plate

Spring Spring

Bearing bush
Cover

Cam

Connection Air
valve

DU1131

• Knock-off
The knock-off must be adjusted so the cyinder will not reach it's end of stroke even with tipping with
max. engine r.p.m.
1. Loosen the lock nut
Loosen the lock nut of the knock-off and turn in the adjust bolt completely.
2. Tip out the cylinder
Tip out the cylinder with a low engine r.p.m. until it reaches it's end of stroke.
3. The adjust bolt
Turn the adjust bolt anti-clockwise until it touches the support which is welded to the oil tank(FCT
cylinders) or base ram(FC & FE cylinders).
4. Lower body
Lower the body and turn the adjust bolt 1 turn anti-clockwise.
5. Tip up the body
Tip up the body with 1750 engine r.p.m. and check if the cylinder reaches end of stroke.
6. When not end of stroke
Repeat 4 and 5 until the cylinder does not reach end of stroke anymore.
7. Lock the adjust bolt
Lock the adjust bolt with the lock nut.

60
 6855

10. DUMP SYSTEM

2-8-g. OIL TANK

Return
line filter
Air breather filter

Oil tank

Bolt
Washer

Tank rubber Elbow

Washer Stop cock

Nut
Hose filter

DU1141

COUTION: a. Fit part names elbow, stop cock, hose filter together and to the tank outlet with
PTFE(teflon) tape.
b. Wind the tape a few times tight around the thread as shown.
c. Do not unscrew, as that damages the tape and causes leakage.
d. If required, use fluid sealant(e.g. LOCTITE 542 or 577).
e. Air breather filter
1) Filter action : 10 µm
2) Filter capacity : 1,350 L/min
3) Temperature range : -40°C~+100°C
4) Max. filling quantity : 40 L/min
f. Return line filter
1) Nominal flow : 150 L/min(clean element)
2) Pressure by-pass : 1.2 bar±10%
3) Peak flow : 300 L/min
4) Temperature range : -25°C~+100°C
5) Replace oil filter twice a year.

61
10. DUMP SYSTEM

2-9. AIR BLEEDING OPERATION

The HYVA main pump, gear pump, and cylinder have no air bleeding screw.
*
1. Sequence for air bleeding operation
1) Slacken slightly the pressure hose of the pump so that air inside the suction hose and pump is
bled out and the system is filled with oil.
2) Slacken slightly the pressure hose and cylinder hose. Allow the pump to operate at low speed and
place the tipping valve in the TIP position. After a while, if air is bled out from the system, tighten
all the joints securely.
3) Because the cylinder piston is locked, a small amount of air remains between the bleeding steps.
If you repeat the tipping operation a few times, this remaining air gets mixed with the oil in the
system and then bled out through the oil.
4) If air still remains in the system even after 8~10 times of tipping operation, check the position of
suction hose and tighten all the joints securely.
Oil temperature and viscosity affects greatly the bleeding operation.
5) As oil begins flowing into the cylinder, hose, and oil filter, fill up the oil tank with oil.
6) Check the working pressure and make sure that the pump works normally.
When the pump operates, if it generates too loud noise or a shock is generated inside the hose,
it indicates that air may be trapped still inside the system, and accordingly the pump howls.
7) Check the working pressure.
Check the entire hydraulic system for normal operation.

62
 10. DUMP SYSTEM

2-10. DIAGNOSTICS AND TROUBLESHOOTING

Complaints Probable cause Correction/Check

• Cylinder would not slip • P.T.O. not engaged • Place the cab control in "IN MESH" position.
off even if the air con- • The pump’s failure to • Disconnect the hose from the valve "P" and
trol is place in TIP po- supply oil check the oil circulation.
sition. • No oil in the tank • Fill up the oil tank with oil.
• Closed stop cock • Open the stop cock.
• Lack of air pressure • Check the accessory for air supply.
• The cylinder connected • Connect the cylinder to the port "C".
to a wrong valve port

• Cylinder slips off only • Air tube connected to • Connect the air tube correctly as directed
when the air control is the valve reversely in the manual.
placed in DOWN posi-
tion.

• Air is fed correctly, but • Faulty air control • Remove all the air tubes except for air sup-
the tipping valve does ply and exhaust, check to see if air flows
not work. through the related ports even if the control
is repositioned correctly. Replace the valve,
if necessary.
• Kinky or restricted air • Check all the tubes for sharp bend. Discon-
tube nect the two air tubes from the valve, relo-
cate the air control to the related position,
and then check the air flow. If air would not
be bled from the end of the air tube, replace
the tube.

• Once the cylinder as- • The descending speed • The descending speed control screw has
cends, it fails to de- control screw has been been tightened completely.
scend or descends tightened completely. • Poor knock-off valve
slowly. • Poor knock-off valve • Faulty air control
• Faulty air control • Restricted return filter
• Restricted return filter • Oil too heavy
• Oil too heavy

• Sufficient air supply, • Oil leak from the inside • Put air control in "lower" position remove
but valve inoperative of the tipping valve pipe from valve "TIP" port. If air leaks from
this prot then the O-ring of the air cylinder
is faulty.

• Valve works properly • Damaged air tube • Replace the O-ring seal.
but suddenly fails. • Plunger clogged with • Check the air tube and replace, if necessary.
dust • Clean the hydraulic system and oil tank, and
• Faulty knock-off valve replace the tipping valve, if necessary.
• Check the knock-off valve.

• Cylinder slips off with a • Entry of oil in the oil • Loosen the adaptor of the pressure hose to
jerk. supply bleed air.

63
10. DUMP SYSTEM

Complaints Probable cause Correction/Check

• Cylinder ascends too • Faulty pump • Replace the pump.

slowly • Too low air pressure • Check air pressure. Check the air control,
air tube, and tipping valve as instructed
above.

• Cylinder does not slip • The relief valve is open • Connect the pressure gauge to a specific
off completely. for oil to return to the port to check pressure at the point where
oil tank, resulting in too the relief valve is open. Set the type plate
great load, or all load and pressure cartridge correctly. If it is dif-
is concentrated on far ficult to obtain this pressure value, contact
front of the deck. the related manufacturer or vendor.
• Too low oil level of the • Fill up the tank with oil.
tank

• The deck descends too • The descending speed • Draw out the cylinder all the way. Place the
fast. control has been com- cab control in “HOLD” position and tighten
pletely tightened. the descending speed control as much as
possible. Place the cab control in “LOWER”
position, and slacken the control until the
deck descends at correct speed.

• Sufficient air pressure, • Select shaft bound or • Unscrew the 3 fixing bolt a half turn and turn
but valve select shaft obstructed. the valve On again. The bolt torque should
inoperative. not exceed 15 Nm.

• Cylinder slips off hard. • Entry of air in the sys- • Perform air bleeding from the system and
tem check oil level of the tank.
• Pump operating ab- • Replace the pump.
normally

64
 10. DUMP SYSTEM

2-11. SERVICE INTERVALS AND CORRECTIVE ACTIONS

1. Walk-around services

1) Check oil level of the oil tank.

Depending on the type of tank, the oil level should fall midway on the sight glass or level

gauge. For a tank without such a gauge, the oil level must be 50mm below the upper side of

the tank.

2) Check the hydraulic system for fault or oil leaks.

2. Weekly or 50 hour services

1) Check all pneumatic joints and hydraulic joints for air leaks and oil leaks.

2) Check whether all the bolts and nuts for are loose and retighten, if necessary.

3) Apply lubricant to all the grease fitting ports on the tipper. Use grease or SAE/40 oil.

4) If the hydraulic oil has been contaminated, empty the oil tank and fill it up with new oil.

5) Check the cylinder for contamination and clean.

6) Check the oil filter and air filter and replace, if necessary.

7) Replace the oil filter and air filter two times a year.

3. Yearly or 1,500 hour services

1) Clean the oil tank and replace oil.

2) Check all the hydraulic joints and replace the hose, if damaged.

3) Replace the oil filter and air filter.

4. Caution

1) Do not apply steam or acid solvent directly to the hydraulic system and cylinder.

2) Do not leave the cylinder, which is not chrome-plated, extended in the outside air for more

than 30 minutes.

3) Do not apply excessive load or uneven load.

4) Do not perform tipping operation on such areas that are not level or the ground is not firm.

5) Do not travel with the deck raised or walk under it.

6) Do not make any change to the hydraulic system.

65