FLUSHING THE HYDRAULIC SYSTEM 2.6 Cleaning The System The first step in cleaning the hydraulic system is to deter- mine if you have visible or microscopic contamination. If the contamination is visible, do the following steps: 1 Change the hydraulic oil by removing the drain plug in the bottom of the hydraulic oil reservoir. (fig. C3661) Be prepared to contain approximately 56 litres(14.8 gal) of fluid. 2 Check the extent of the contamination by disassem- bling 1 each of the hydraulic cylinders. Check the cylin- ders for damage. Repair or replace the cylinders as required.
If you determine the damage was caused by severe contamination and is not the result of normal wear, it will be necessary to remove, clean and repair all valves, pumps, lines, cylinders, etc. 3 Replace all hydraulic filters. 2 If the contamination is determined to be microscopic, per- form the following steps: 1 Change the hydraulic oil by removing the plug in the bottom of the oil reservoir. (fig. C3661) Be prepared to contain approximately 56 litres (14.8 gal) of fluid. 2 Connect an external 5 micron filtering system, capa- ble of sustaining minimum of 2000 PSI (138 Bar) and has a back pressure gauge, to the auxiliary couplings. (fig.
C3646) 3 Start the engine and let it idle at approximately half throttle. Replace the hydraulic filter WARNING Be sure to use a filtering system capable of handling the pressure of the hydraulic system. 4 Engage the auxiliary circuit. Check to make sure the filtering system is not over taxed by the loaders hydraulic system pressure. Adjust engine idle accordingly to match the filtering systems capacity. This may vary as the filter becomes dirty, you may need to decrease engine RPM. Circulate the oil through filter for 30 minutes. 5 As the oil is being circulated through the auxiliary circuit, raise the liftarms up and down in full stroke cycles. Repeat this exercise for 15 minutes.
6 Cycle the bucket tilt cylinders in the same manner as above. Repeat the exercise, in full extension and retrac- tion, for 15 minutes. 7 Install new hydraulic oil filters. (fig. C3650) 8 Start the engine and check for leaks. Replenish the hydraulic oil reservoir as required. (fig. C3431) C3650 Hydraulic reservoir sight gauge Oil level C3431 2-12 Hydraulic reservoir Oil drain plug C3661 Flush the fluid to an C3646 Flush the fluid to an external trap filter C3646