JAC Dumper truck. Service Manual — part 7

Special notes:
Before starting driving, make sure that the control handle is on the "fall" position so as to avoid the accidental carriage
lifting when the car is moving. The power take-off also needs to be switched off. Otherwise, the gear pump will continue
working, which will result in the excessive wearing and early damage of the pump.

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Working Principle and Operation Instructions of Electricity-controlled Dumping Mechanism
1. Working principle of the hydraulic system
音 The working principle of power take-off control system (see Diagram 5)

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Diagram 5 illustrates the working principle of power take-off control system. When the switch is turned on, the com鄄
pressed air in the reservoir will flow to the power take-off cylinder through the electromagnetic valve, which will push the
gear of the power take-off to mesh with the gear of the transmission. When the power is turned off, the air in the cylin鄄
der袁under the influence of the return spring of the power take -off cylinder, will be discharged into the environment
through the vent of electromagnetic valve. The gear of the power take-off will be separated from that of the transmis鄄
sion, cutting off the power of the pump.
音 The hydraulic principle diagram of dumping system

1. hydraulic oil tank
2. gear pump
3. electromagnetic gas valve
4. air tank
5. 3-gang switch
6. air slide valve
7. hydraulic oil tub
8. the fuse

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Diagram 6 shows the hydraulic principle of the dumping system. From it we can see that the carriages in the system can
pause or fall down, free of the influences of the oil pump's working conditions. Namely, as the carriages are being
paused or falling, the oil pump can still be at work. The simplification of the operation in the pausing condition is achiev鄄
able. The air slide valve, numbered 6, which is factually a 5/4 way air control valve, helps lift, pause or drop the car鄄
riages by means of the switch (numbered 5). When the air control valve is on the left, the hydraulic oil flows through the
oil tank (1), the gear pump (2), and "P"& "A": the entrances to the air control valve fall down towards the bottom of the oil
tub, the carriages are lifted. The oil on the upper part of the tub, however, retreats to the tank by way of "B" &"O". In the
case where the air control valve is in the middle (as is signified in the diagram), the line along which the hydraulic oil fi鄄
nally returns to the tank consists of the tank, the bump gear and entrances "P"& "O"; now the carriages are paused. On
the right as the air control valve is (the carriages having been raised), part of the oil, due to the gravity of the carriages,
comes back through entrances "A"& "O" to the tank; still a certain amount of the oil goes back, passing the tank, the
bump gear and entrances P&O. Meanwhile, the downward movement of the tank's pistol renders the upper part of the
tank vacuum. Some oil, under this situation, enters the upper part of the tank through entrance B.

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2. The operational methods
音 The PTO (Power Take Off) System
Get the engine started and make sure if it is at usual work; remember not to invigorate the gearlever. The moment the air
pressure gauge tells that the air pressure of the brake system exceeds 0.4Mpa, separate the clutch, and then, a few
seconds after the power is cut off, give a press to the button, which serves as the self-lock switch of the PTO, to turn it
on. Afterwards, slowly put through the clutch. With all of the above-mentioned procedures done, the oil pump, driven by
the PTO output shaft, is set in motion. To remove it out of work, just separate the clutch and press the button to turn off
the PTO.
音 The Lifting of the Carriages
With the oil pump at work, press the self-lock switch button for lifting and transfer the handle from "O" to "lifting", the
carriages are so raised. When they reach the most possible height, the lifting itself is no longer under way, because of
the automatic oil spill of the system. The speed of the lifting, though, is in direct proportion with that of the engine's ro鄄
tating. What should be heeded is that it is inadvisable for the carriages to be lifted too fast. Mostly, for the lifting, the en鄄
gine needs to be set under the condition of medium accelerograph, and the engine's rotating speed should be kept be鄄
low the maximum, in case the oil pump should rotate over fast, thus bringing about self-damage.
音 Bringing -down and Relocating the Carriages
As soon as the carriages are unloaded, the quicker they are brought down the better they are relocated. Press the self-
lock switch button for lifting, turn the handles from "lifting", past "O", to "bringing down", then the carriages go into gradu鄄
al falling until the final relocation comes. Now, again press the button and maintain the handles of lifting and TPO at "O";

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the vehicle gets started without delay; and the accidental lifting of carriages is simply out of question.
音 The Pausing of the Carriages
Suppose you want them to stop at a certain angle (0耀48毅) when they are being lifted or bought down, what you need to
do is merely to turn the lifting switch to "O". A momentary pause does not claim the cut-off of the PTO power, which di鄄
minishes the degree of the operational complication. Long-time pausing, however, asks for the cut-off of the power;
such being the case, the pump quits working. Therefore, improper operating which harbors accidents is hampered and
the amount of unnecessary oil-consuming finds itself reduced.
Notice: You ought to bear in mind that the controlling switch of TPO complies with electricity -liquid circuit and that of the
lifting electricity-gas-liquid circuit. So, when it comes to operating, the voltage of the battery must stay at no less than
24V and the air pressure of the gas container at no less than 0.4Mpa. Otherwise, neither the solenoid valve nor the air
slide valve would work as usual. Worse still, the valve core being closed is not tight enough, it occurs that the carriages
refuse to be lifted and paused in a steady way.

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The Working Principle and Operational Instructions of the Dumping Mechanism Controlled by Combinative Electricity-Gas
1. The Working Principles of the Hydraulic System
音 Principle of the power take off system
For the knowledge of the principles of the PTO system, check it back in渊樱冤1尧渊1冤

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音 The Hydraulic Principle Diagram of the Dumping System(see Diagram 7)
From the diagram, you can grab the idea that, in the system, the pausing and falling of the carriages are independent of
the working condition of the oil dump. In other words, while the carriages are being paused or bought down, the working
of the oil pump still continues, so that the operation of the mid-parking procedure is simplified. Valve (1) is an air valve;
it relies on the manipulation of valve (2) to direct the high pressure gas, and furthermore, to control the lifting valve, for
the sake of steering the carriages freely. When the carriages reach a certain height, some part of them push open the
limit valve, and the air path gets cut through. Here comes the right occasion to unload the carriages. As for the hydraulic
lifting valve, it functions like this: as valve (1) is on the right, the hydraulic oil, pressurized by the pump, passes through
entrances "P"& "A" down towards the bottom of the tub. At this moment, the carriages are on the lift. In the middle as the
valve is, two kinds of situation account for the pause of the carriages. Firstly, the pressurized hydraulic oil, past the
check valve and the dumping valve, returns to the tank; or, with the PTO turned off, the oil pump quits working. The oth鄄
er kind of condition should be the one in which the hydraulic oil in the tub is blocked. Likewise, two kinds of reasons are
sound for the falling of the carriages. Of them, the first one shares the same nature as the first one just above-men鄄
tioned; and another should be the fact that the oil in the hydraulic tub, by way of entrances "B"& "A", finally retires in the
tank.

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2. The Operational Instructions
音 The PTO System( as for its operational instructions, see 渊樱冤2尧渊1冤)

音

The Lifting of the Carriages

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As the PTO is on, switch the handle of the air control valve to its "lifting" position, and the carriages automatically rise,
upwards till the pre-designated height. At this instant, the limit valve opens itself, the oil becomes released, and the lift鄄
ing itself is over. The lifting pace of the carriages walks together with that of the engine's rotating. If you use the mid-
carriages to do the lifting, you had better not operate them in a hasty way. Normally, in lifting, the engine should be set
in the medium accelerator and rotate within the maximum speed; otherwise, the oil pump is likely to be damaged.

音

Bringing down and Replacing the Carriages

Switch the handle of the air control valve to its "bringing down" position, and the carriages, thanks to the help of their
own gravity, will fall down back into the total replacement. Now, the handle should be placed at "pause", so as to pre鄄
vent the carriages, in moving, from being accidentally lifted. The area the handle you switch around covers, in a sense,
commands the falling pace.
音 The Pausing of the Carriages
When the carriages are being lifted, release the handle and it will come back to the "pausing" position itself; yet if they
are falling, you have to turn the handle yourself. The carriages thus stop at their current places in either case.

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The Working Principle and Operational Instructions of the Double Cylinder Side Dump
Its principle is demonstrated by Diagram 9 and its operational instruction can be referred to in 渊樱冤尧

1. air tank
5. 3-gang switch
2. air control valve KQF34-B
3. Position control air valve XQF23
4. air control distributing valve
5. hydraulic oil tank
6. check valve
7. oil pump
8. oil tank

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1. Lift the carriages
If you want to lift the carriages, just turn the air control valve (2) to the position proper for "lifting", afterwards, the pres鄄
surized oil, past the multi-functional distribution valve(numbered 4) straight into the bottom of every oil tub, and now, it's
available to do the lifting.
2. The Pausing
At the "pause" position as the air control valve is, it does not matter either the carriages are moving upwards or down鄄
wards, the pressurized oil, through distribution valve 4, will thus circulate for the dumping. It turns out that the output of
the pressurized oil would cease, and the non-return valve, set in the distribution valve, is forced to be closed, under the
effect of the oil pressure prevailing the tubs' bottom parts. Since there is no way for the oil to flow back, the carriages
have to stop at a certain place.
3. The Falling
Switch the air control valve to the "falling" part; then the hydraulic oil, with the help of the carriages' gravity, retreat to the
tank by way of the distribution valve. The carriages then begin to move downwards.
4. The Fixing of the Carriages
In the procedure of their rising, a pre-designated height is there for the carriages to push open the distribution valve 3.
And the pressurize oil find their way through the non-return valve back into the tank, the carriages hereafter stop the
motion.
5. Safe pressure regulation
The pressure of the multi-functional distributing valve is regulated when delivered. If the customers have special de鄄

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mands, it can be regulated accordingly. But this must be done with the consultation of the factory. If not, the factory will
not be responsible for any possible problems.
Note: The operation of power take-off on the dump truck installed with gearbox, like Shanxi Fuller transmission:
Turning on of the power take-off
Only when the truck is in the low gear (1-4gear) will power take-off be used. The procedure of turning on the PTO is as
follows:

荫

Step down the clutch pedal;

荫

Turn on the neutral gear and the power take-off in turn;

荫

Shift gear, and release the clutch, then the power take-off will be turned on and the dumping indicator on the dash鄄

board will shine. (Only when the truck is in gear can the power take-off function.)
Turning off of the power take-off:

荫

Step down the clutch pedal;

荫

Shift the gear lever to the neutral position;

荫

Turn the PTO and neutral gear on the dumping control structure to the "off " position, release the clutch, then the PTO

will be turned off and the dumping indicator on the dashboard will go out. The driving power train is connected now.

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TIPS OF USAGE

1. Check before driving the handle of the operational valve and the switch of the power take-off, and make sure they
are on the "pause" position. Make sure the gear pump is not at work, lest the carriage will lift automatically on the way
and cause unnecessary losses.
2. To make the gear pump work in the process of lifting or landing, step down the clutch pedal first. Otherwise, it will
cause serious wear to or break the PTO gears when they joggle.
3. When the dump truck are fully loaded, check whether the manual handle, hook and other parts are open so as to
make sure the door can be opened normally in the process of lifting, in case there are large accidents such as the
turnover of the truck.
4. During the lifting of the carriage, the engine speed should not exceed 2400r/min as to avoid the damage of the oil
pump when it exceeds the speed limit or the turnover of the carriage because of the imbalance caused by quick lifting.
When it is lifted nearly to the biggest angle, do not accelerate, or the carriage may be over lifted, which will further
cause the back carriage to hit the ground and be distorted, the big carriage to turn over and be damaged, and other
damage to other parts in charge of lifting.
5. When the dump truck are loaded by other machines, make sure the machine pours the cargo into the carriage in a
low position. Otherwise the strong bump will cause damage and distortion to the bottom board or even the girder of the
main machine and other parts.
6.

Check consistently whether there is leakage of the dumping system. When filling into the tank the hydraulic oil,

check whether the filter mesh at the mouth of the tank is damaged, and change it when necessary. Otherwise the impu鄄

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rity will go into the tank and cause damage to the hydraulic components. Do not fill the tank with the mixture of different
brands and types of hydraulic oil or the oil which is on the instructions.
7. Always check the engagement condition of power take-off and gear pump to avoid the accidental lifting of the car鄄
riage caused by incomplete separation of the gears. Besides, pay attention to the unusual phenomena such as the ab鄄
normal voice and overheat under the working condition in order to expel them in time. Or they will cause earlier damage
to the power take-off, gear pump, valves and other parts.
8. Always pay attention to the condition of the hydraulic cylinder and other parts when lifting. There should not be phe鄄
nomena like binding, sliding, jumping or abnormal sounds. These abnormal phenomena should be fixed in time to avoid
the earlier damage to the oil tank.
9. Always check whether the locking structure of the back carriage is in good condition, and make sure it is in the right
angel capable of automatic open and close to avoid the trouble or accidents caused by the accidental open of the back
carriage or when it doesn't open during lifting. When dumping large rocks, heavy lumps or other similar objects, remove
the back carriage to avoid damage to it.
10. During maintenance, pay attention to the working planes of the hydraulic cylinder and the gear pump to see whether
there are bruises and scores, because they will damage the function of the hydraulic cylinder.
11. Pay attention to the solitariness in maintenance, in case that the impurity such as silt and thread residue will infiltrate
into the hydraulic system to pull the components and block the valves and finally damage the working function.
12. If the tipper has not been used for a long time, it must be inspected following the inspection contents for the new
one and then can be reused.

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13. You should inspect the conditions of such parts as the carriage, second frame and spare wheel frame, and deal with
such problems as loosening and sealing off to avoid serious accidents.
14. You should examine whether the main frame and second frame are connected firmly, whether U wire and iron are
loose, whether the punch is padded, the cushion and rubber cushion block are fixed, and if they are loose or in version,
you must fasten them and put them the right place and cannot transport goods and unload them, for the frame, the sec鄄
ondary frame and lift system will be deformed or damaged, the tipper will even be turned over, which will threaten safety
of life and property.
15. Loading, transportation and unloading

荫

The goods should be distributed evenly and can not run over the carriage itself, and their density should not be over

1600Kg/m3 with their rest angle be smaller than 45 centigrade;

荫

The fully loaded vehicle should be driven at an appropriate speed according to road condition. When it is inclined in

bad road, it can only be moved on the condition that the goods have been discharged. They can be taken out by manu鄄
al labor from the carriage (if the carriage is mobile, they can be taken out from the side door) and cannot be taken out
by lifting system.
16. Important suggestion: in any of the following conditions, the vehicle will possibly be damaged and accident will take
place. Please pay special attention to them and do not operate in the situations A~I (altogether 9 kinds).

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A. Running or lifting them when goods are being loaded will:

荫

make both the vehicle and man in insecure situation

荫

shorten the service life of the vehicle

荫

damage in the earlier period the refitted part

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B. Running or lifting them when the goods are unevenly loaded will

荫

make the vehicle turn over

荫

make the tire burst and the carriage and frame deform

荫

distort and damage lift system and make the vehicle prone to accidents

C. Unloading the goods on a slope with an angle of over 5 degrees or on soft
ground will:

荫

make the vehicle turn over easily and lead to death and loss of property

荫

deform or damage easily the lift system

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D. Lowering the carriage fall suddenly when the goods have not still been un鄄
loaded will

荫

distort or destruct the lift system

荫

deform the frame and chassis, make the tire burst and even lead to other

serious accidents

E. Driving the vehicle forward when the goods are unloaded partially will:

荫

make the vehicle out of control, front wheels off ground and the tipper turn

over etc because of high gravitational center

荫

distort or damage lift system, frame and back hinge point because of high

gravitational center

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F. If man remain under the carriage that has not yet been propped or propped
firmly,

荫

his life will be in danger when hydraulic system leaks or control system

stops functioning suddenly

荫

accident will take place if the carriage fall suddenly by other's wrong oper鄄

ation

G. If man remains in the working area of the tipper or unload the goods in the
place where there are other interferences,

荫

such accidents as people are injured by carriage and goods, electricity

wire cut and carriage or other equipments damaged will be easy to happen

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H. If you drive the tipper when the carriage is still being lifted,

荫

the lift system will be damaged, the carriage crashed, the electricity line

cut, other equipment destructed and even life is in danger

I. If the tipper is lifted out of its limit,

荫

the carriage will turn over, hydraulic cylinder and other components be

damaged, the back carriage crashed and opening destructed

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Special notes

荫

All the above-mentioned notes apply to all kinds of dump truck produced by our company

荫

Driving against the rule and disobeying the above motes are regarded as signs of users' giving up the right to be

served by us, and all the consequences and responsibilities brought about will be undertaken by users instead of us.

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TECHNICAL MAINTENANCE

Regular technical maintenance can help avoid the early abrasion of motion parts, reduce the accident frequency when
the vehicle is used and stop some potential accidents, so it is a key point to improving the efficiency and prolong its ser鄄
vice life. The details are:
1. The new vehicle should be loaded in strict compliance with the rules in its running-in period;
2. Everyday before and after you drive your vehicle:

荫

Inspect the hydraulic oil amount and add more if the oil is inadequate; inspect whether hydraulic system is damaged

or leak, and repair it if so:

荫

Inspect whether such parts as the top and bottom bolster of the hydraulic cylinder and connecting rod are connected

and fixed. Observe whether all the motion parts and their neighboring fixed parts are damaged or deformed;

荫

Inspect the condition of the carriage, second frame and spare wheel frame and observe with special attention

whether the weld joints are open or cracked; inspect the work or abrasion conditions of gear pump, power take-off and
hydraulic cylinder, maintain and repair or replace the damaged parts.
3. Every week or after 50 working hours:

荫

Inspect all the gas lines and hydraulic tie-ins leak, if so, replace the damaged hoses;

荫

Inspect all the bolts and nuts to see whether they are loose, if so, fasten them;

荫

Inspect all kinds of velvets and hydraulic cylinder, and clean them if they are dirty;

荫

Inject oil to all the injection locations once to ensure the vehicle can work normally;

荫

Inspect the conditions of stow-wood, rubber cushion blocks and rubber cushion belts, and replace them in time if

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they are corrupted or aged.
4. The high pressure hoses must be changed every other year, and must be replaced in time if they are damaged or
swell partially;
5. The hydraulic oil must be kept clean and can not contain water and impurities; it must be changed regularly and its
deposits be cleared; hydraulic oil must deposit 48 hours before injected into oil tank; the filtration accuracy of hydraulic
oil should be lesser than 25滋m.(The oil tank must be cleaned once each week or after 50 hours; the hydraulic oil should
be changed once when the carriages have been lifted 600-800 times, and must be changed any time when the oil is
dirty or aged; the longest period is one year.)

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Attachment: the main lubrication points and their locations of all kinds of dump truck:
A. The lubrication diagram of direct push tipper with front cylinder

1. the hinge point between cylinder and top frame (two places)
2. the hinge point between cylinder and bottom frame (two places)
3. the hinge point between top frame and bottom frame (two places)

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B. The lubrication diagram of composing tipper with cylinder and front push connecting rod

1. the hinge point between arm and top frame (two places)
2. the hinge point between arm and top of lift cylinder (two places)
3. the hinge point between arm and drawbar (two places)
4. the hinge point between lift cylinder and bottom frame (two places)
5. the hinge point between drawbar and bottom frame (two places)
6. the hinge point between top frame and bottom frame (two places)

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C. The diagram of composing tipper with floating cylinder and connecting rod

1. the hinge point between arm and bottom frame (two places)
2. the hinge point between arm and bottom of lift cylinder (two places)
3. the hinge point between arm and drawbar (two places)
4. the hinge point between top lift cylinder and top frame (two places)
5. the hinge point between drawbar and top frame (two places)
6. the hinge point between top frame and bottom frame (two places)

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D. The lubrication diagram of drop side tipper with double cylinders

1. the hinge point between top cylinder and carriage (two places)
2. the hinge point between bottom cylinder and secondary frame (two places)
3. the hinge point between carriage and secondary frame (two places)

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Notice

荫

All the lubricate parts mentioned above must adopt auto general lithium grease No.2.

荫

Don't apply any grease to the surface of lift cylinder or piston lever. Wipe away the stains using dry silk fabric or a tow鄄

el.

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TRANSPORTATION AND STORAGE

1. When transported by railway or water, the tipper should be lifted using lifting equipment, in case of damages to the
products.
2. The products should be fastened to ensure security and avoid accidents during the transportation.
3. When the tipper is kept unused for a long time, keep it according to the rules about the cart refitting and chassis
maintenance.

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TROUBLE SHOOTING院

possible problems

analysis of reasons

solutions

Operational valve
is in the lifting po鄄
sition, but the car鄄
riage is not.

1.power take-off doesn't joggle
2.insufficient oil amount in the oil tank
3.malfunction of the control system

荫

lack of voltage or obstructed circuit

荫

lack of air pressure or air leakage

荫

electromagnetic valve malfunction

4.oil leakage of the hydraulic system
5.too much inner leakage of gear pump
6.directional control valve isn't shut
7.the plug doesn't recover the original position
when in the limited valve
8.too much leakage in the oil tank
9.the operational valve doesn't work

1.solve the gear engagement problems, repair or
change the power take-off.
2.put the oil in the tank according to the rules
3.solve the control system problems

荫

fully charge or connect the circuit

荫

inflate the system or repair the leakage parts.

荫

repair or change the electromagnetic valve

4.repair the oil leakage parts
5.change the gear pump
6.cheek if the plug is blocked up and adjust it
7.check and adjust the post guide and plug
8.change the gasket set or oil tank
9.repair or change the operational control valve

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possible problems

analysis of reasons

solutions

The carriage is not
lifted to the proper
position or doesn't
stop after being lift鄄
ed

1.shortage of hydraulic oil amount
2.the directional control valve isn't fully shut
3.one-way valve leakage
4.valve moves up and down when in limited
valve
5.inner leakage of the gear pump

1.fill up with the hydraulic oil
2.check, maintain and change for new ones.
3.check and change for new ones.
4.refit the limited valve.
5.change the gear pump.

The carriage moves
up and down when
lifted or is lifted too
slowly

1.air in the hydraulic system
2.the directional control valve isn't fully shut
3.some inner leakage of the gear pump
4.small holes on the oil tank filter are blocked up
5.one-way valve is blocked up
6.shortage of hydraulic oil

1.re-lift to let out the air
2.adjust the directional control valve
3.change the gear pump
4.check and change the oil filter and the hy鄄
draulic oil
5.repair and change the one-way valve
6.fill up with the hydraulic oil

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