CG938H Wheel Loader. Manual - part 32

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Working device and hydraulic steering system 

Replacement of hydraulic oil box 

The machine shall be on level ground, set all working devices in the ground and exert 

downward pressure on them. Close the parking brake and shutdown the engine. 

1． Disassemble the oil filling cap of the hydraulic tank. 

2． Open the vent valve at the bottom of the hydraulic tank and discharge the oil. 

3． Close the vent valve. 

4． Replace the filter of hydraulic system. See “Hydraulic System” in “Maintenance of Each 

500 Working Hours or Every Season”. 

5． Disassemble the fuel strainer, clean it and install it. 

6． Refuel to the hydraulic tank. See “Viscosity and Full Capacity of Oil”. 

7． Check the gasket of the oil filling cap and replace the damaged gasket. 

8． Fit on the oil filling cap. 

9． Start the engine and run it for a few minutes. 

10． 

Maintain the hydraulic oil level in the middle of the oil gauge, and if necessary, refuel 

it through the oil filling port. 

11． 

Shut down the engine. 

9.4 Maintenance of Each 50 Working Hours or Every Week   

Prior to carrying out any operation or maintenance, 

the warnings and annotations in this manual’s safety 

chapter shall be read and understood. 

z  Firstly carry on the aforementioned examination 

items 

Lower hinge pin of dipper 

Lubricate the hinge pin   

Lubricate two hinge pins under the dipper. 

9.5 Maintenance of Each 100 Working Hours or Every Two Weeks 

Prior to carrying out any operation or maintenance, the warnings and annotations in this 

manual’s safety chapter shall be read and understood. 

Replacement of transmission fluid 

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After working for 100 hours, the transmission fluid of the new loader shall be replaced. 

Start the engine to hear the oil and the machine shall be set at a level position. Set down 

the bucket and exert downward pressure on it slightly. 

Close the parking brake and shutdown the engine. 

1．Disassemble the oil drain plug at the bottom shell of the gearbox to discharge the oil, 

clean and fit on the oil plug. 

2．Disassemble the oil drain plug which locates below the torque-converter’s oil radiator at 

the backmost of the machine and discharge the oil. Clean and fit on the oil plug. 

3．Replace filter. 

4．Fill up oil with special volume into the torque-converter and fill to the high position of the 

oil gauge when the machine is offstate. 

5．Start engine and pedal the service brake. 

6．Under the idle speed, slowly manipulate the joystick of the gearbox, and recycle the oil so 

that oil torque-converter and pipeline may be full of oil. Check the oil level of the 

torque-converter which shall between the low and high level of the oil gauge. 

7．Set the joystick of gearbox at stop short, shutdown the engine and park it well. 

After it is replaced the machine works for 1000 hours later, the transmission fluid shall be 

replaced once each 1000 hours. If the machine does not work for 1000 hours every year, 

the transmission fluid shall be replaced one time. 

Specific see “Instructions of 4WG200 Power Shift Gearbox”. 

z  Firstly carry on the aforementioned 

examination items 

Oscillating frame of rear axle 

Lubricate the two lubricating joints of the 

oscillating frame of the rear axle. 

Hinge pin of hydraulic oil cylinder and tie bar 

Lubricate 11 hinging joints of the working 

device (excluding two hinge pins of the dipper). 

Steering cylinder’s hinge pin 

Lubricate 4 bearings of the left and right steering cylinders. 

Articulated bearing of front and rear frames 

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Inject lubricant 

Lubricate the upper and lower articulated bearings of the front and rear frames. 

  Air conditioning System 

1． For the integral air conditioning system, do not dismantle it randomly so as to prevent the 

condensator from leakage. Examine it regularly; especially examine whether the pipe 

joints are loosened and whether the collecting screws are loosened. For any problem, the 

corresponding measures shall be taken. 

2． Regularly examine the belt for proper tightness. Usually, after working for 100 hours, it 

shall be examined one time. Please see the “Regulation of Belt” in the chapter of “Air 

Conditioning” for details.   

3． Regularly clean the dust on the surface of condenser. It may be cleaned with water or 

high-pressure air blower to prevent weakening the condensation effect. Usually, after 

working for 100 hours, it shall be cleaned one time. Spray rinsing with steam is not 

allowed. 

4． While removing the system refrigerant, discharge it slowly to avoid randomly discharging 

of the antifreezing oil. Keep it away from skin. 

5． While replacing the parts, add the antifreezing oil according to the requirements. 

6． The expansion valve has been adjusted well according to the relevant regulations. Do not 

adjust it without authorization. 

9.6 Maintenance of Each 250 Working Hours or Every Month 

Prior to carrying out any operation or maintenance, the warnings and annotations in 

this manual’s safety chapter shall be read and understood. 

z  Firstly carry on the aforementioned examination items 

Engine oil and filter 

Replace engine oil and filter 

1． Disassemble the oil drain plug of crankcase, discharge oil, clean the plug and install it. 

2． Open the machine’s left maintenance door, disassemble the filter with a zonary wrench. 

3． Clean the filter’s shell base, remove all old filter gaskets. 

4． Smear new filter gasket with a thin layer of engine lubricant.   

5． Install new filter by hand, tighten it for semi-circle when the gasket touch the base. 

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6． Disassemble the oil filling cap, and add fresh oil into the crankcase. See also “Viscosity 

and Full Capacity of Operation Oil”. Clean the oil filling cap and install it. 

7． Start the engine to heat oil, detect leakage, and shutdown the engine. 

8． Maintain the engine oil in the normal position of oil gauge. 

9． Install the maintenance door. 

Braking system 

Test the braking capacity of the service brake. 

There shall not have any people and obstacles around the machine. 

Fixed link of the front and rear frames shall be packed up.   

Test the brake on dry road. 

The following tests are used to determine whether the service brake functions are normal 

or not, not to measure the maximum braking force. The vehicle braking force needed by the 

engine running at a certain speed is adapted with the setting value of the engine and the 

efficiency of the driving system, as well as the braking capacity of the brake. 

When the machine begins moving, the revolving speed of the engine when braking, the 

service brake shall be compared with that of the engine as braking stopper is under the 

original test, and shall be a system wear symbol. 

1． Start the engine, slightly raise the bucket, brake the service brake, and release the parking 

brake. 

2． When braking the service brake, put forward the gearshift at the second gear. 

3． Gradually increase the revolving speed of the engine to high speed idle, and the machine 

shall not move. 

Warning 

When the machine begins moving, immediately reduce the revolving speed and 

close up the parking brake. 

4． Let the revolving speed of the engine drop to low speed idle, set the gearshift to stop short, 

close up the parking brake, put the bucket on the ground, and shutdown the engine. 

 

Caution 

If the machine still moves when tasting the service brake, please connect with 

related service station and allow serviceman to check the machine. If necessary, the 

service brake shall be repaired before reuse of the machine.