Chapter 2: Maintenance and repairing a motor grader

2.1 Introduction A motor grader is a piece of heavy machinery used to create a smooth, wide, flat surface. Traditionally, the grader is used for road maintenance its main function is to flatten surfaces before the application of asphalt. Presently, these machines are also commonly used for fine grading, spreading, and earthmoving. They can be used for clearing debris and brush, as well as for snow removal. A variety of attachments convert the motor grader into a more versatile machine, enabling the machine to do things such as dig shallow holes. The attachment of an elevating conveyor enables the machine to take loose material from the trailing end of its blade, elevate it, and cast it into a hauling unit.

Fig 2.1: Komatsu motor graderIn generally motor graders need regular maintenance schedule because of its heavy use. In motor graders work done was measured by hours. So these maintenance were done based on hours.2.2 Parts of a motor graderFig. 2.2: Parts of a motor grader (Outer)Fig. 2.3: Parts of a motor grader (outer 2)

Fig. 2.4: Parts of a motor grader (Inner)

1. Steering wheel 7. Decompression leaver 2. Accelerator leaver8. Turn signal switch leaver3. Accelerator paddle9. Gear shift leaver4. Break paddle 10. High-low leaver5. Clutch paddle 11. Gear shift leaver6. Hand break leaver 12. Forward-Reversed leaver 13. Hydraulic control leavers2.3 Maintenance of a motor grader

As above mentioned motor graders needed regular maintenance and those maintenance are based on working hours. Those maintenance were divided in to 10 hour, 100 hour, 300 hour, 600 hour, 1200 hour maintenance.

2.3.1 Every 10 working hours or daily maintenance

1. Walk around checks Hydraulic system-Check for leakages, worn hoses and damaged lines Electrical System-Check for loose connections and open circuits Scarifier-Check for wear and damage Tires-Check for wear, cuts or gouges Blade-Check for wear and damage Engine compartments-Check for oil and fuel leaks Clutch and transmission-Check for leakages Cooling system-Check for worn hoses, leakages and thrash build up Operation-Check for noise and vibration 2. Check oil level in engine crank case

Fig. 2.5: Oil filter of a motor grader Prefect oil level should be between full and add marks on gauge (1) If there is not enough engine oil , it was added to the oil filter (2) Oil level was checked after 5 minutes of engine stopped

3. coolant level in radiator was checked

Fig. 2.6: Radiator cap and radiator inlet Coolant should be up to bottom of the filter. If there is lack of coolant water was added to the radiator inlet(2)

4. Oil level in the hydraulic tank was checked

Fig. 2.6: Hydraulic tank of motor grader (6) Oil level should be between full and add in the oil gauge provided If there is lack of hydraulic oil, it was added to the oil filter

5. Steering wheel play was checked

Fig. 2.7: Motor grader steering wheel Motor grader steering wheel should be checked for the play of the wheel Standard play should between 10 to 12cm (about 4 inches) when measured at wheel rim

6. Blade attachments of motor grader was checked

Fig. 2.8: Blade attachment of motor grader Scarifire and blade was checked for wear and damages Sacrifire teeth (1) or blade cutting edges were replaced if it worn or damaged

7. Tyres and rims were checked

Fig. 2.9: Tyre set of a motor grader Tyre set was checked for damages, were and the fitting nuts of the wheel were checked

2.3.2 Every 100 working hours or monthly maintenance

1. Oil level in the clutch and flywheel was checked There as a special gauge in the clutch to check the oil level. In generally oil level should be between full and add marks on the gauge Oil was added to the oil reservoir

2. Electrolyte level in the battery was checked Electrolyte liquid should be above 1cm (3/8 inches) above the cell plates Distilled water was poured if it is necessary

3. Moisture and sediment was drained from fuel filter Moisture and sediment was collected in the fuel filter because of the impurity of diesel and the machine exposed to the rain To clean the oil filter first the oil supply line was closed and then the air plug was loosen. Then the drain plug was removed and let the moisture and sediment to go out. Then the oil filter and the drain plug was cleaned and attached to their positions

4. Blade, circle and guide plates were lubricated

Fig. 2.10: Blade (1), Circle (2), Guide plate (3) of motor grader

Sliding surfaces of the blade, circle and guide plate was cleaned and gear oil was applied to those surfaces.

5. Adjust fan belt tension was checked

Generally the deflection should be 2 to 2.5 cm(3/4 to 1 inch)

6. Clutch pump drive belt tension was checked and adjusted

7. Air master was checked for air and oil leakages

8. Clutch booster was checked for oil leakages

Fig. 2.11: Clutch booster2.3.3 Every 300 working hours or 3 month maintenance

1. Oil level of the transmission gear case was checked

Fig. 2.12: Transmission gear oil gauge (1)2. Oil level in rear axle gear case was checked

Fig. 2.13: Gear case of motor grader Level plug was removed and the oil level was checked Oil level should be at the bottom of the plug opening

3. Oil level in the tandem drive gear case was checked

4. Oil level in the circle reverse worm gear case was checked

Fig. 2.14: Circle reverse worm gear case5. Oil level in reverse reduction gear case was checked

6. Fuel feed pump per filter was washed

7. Crank case oil and filter was changed

First the engine was warm up Then the drain plug was removed and allow oil to drain The bolt at the center of the filter case was removed and the filter element was taken out from the case New elements were placed and the case was cleaned Oil filter was filled with 19 liters of oil Engine was run in low speed and the oil level was checked Oil was added if it is needed

8. Air cleaner element was cleaned

9. Wheel nuts were checked and retightened

10. Air master was lubricated

11. Steering wheel shaft joints were lubricated

12. Drawbar ball joint was lubricated

13. Hydraulic control levers were lubricated

14. Clutch pump bearings were lubricated2.3.4 Every 600 working hours or 6 month maintenance

1. Fuel filter element was changed

2. Hydraulic filter element was changed

3. Steering wheel intermediate shaft bearing was lubricated

4. Circle reverse universal joints were lubricated

5. Transmission gearshift lever was lubricated

6. Hydraulic pump universal joints were lubricated

Fig. 2.15: Hydraulic pump universal joints (1 & 2)7. Shear pin flange was lubricated

Fig. 2.16: Shear pin flange (1)

2.3.5 Every 1200 working hours or 12 month maintenance

1. Engine cylinder head bolts were retightened and the valve clearance was adjusted

2. Oil in the flywheel clutch case was changed

3. Oil in transmission gear case was changed

4. Oil in the rear axle gear case was changed

5. Oil in the tandem drive gear case was changed

6. Oil in the hydraulic tank was changed

7. Cooling system was flushed and coolant was changed

8. Air cleaner element was changed

9. Steering wheel shaft and spline shaft was lubricated

10. Ball joints of the attachment was lubricated

11. Circle to draw bar clearance and circle to guide shoe clearance was checked