2-13
2
FLUSHING THE HYDRAULIC SYSTEM 2.7
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. C4446)
Be prepared to contain approximately 30 litres 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.
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. C1034) Be prepared to
contain approximately 30 litres of fluid.
2
Connect an external 10 micron filtering system, capa-
ble of sustaining minimum of 2000 psi (138 bar) and has
a back pressure gauge, to the auxiliary couplings. (fig.
C1687, C1688)
3
Start the engine and let it idle at approximately half
throttle.
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. C1472)
8
Start the engine and check for leaks. Replenish the
hydraulic oil reservoir as required. (fig. C1878)
Cleaning The System
C1687
C1688
C1472
C1878
Oil level
C4446
Oil drain plug
Hydraulic reservoir
Hydraulic reservoir sight gauge
Replace the hydraulic filter
Flush the fluid to an external trap filter
Be sure to use a filtering system capable of handling
the pressure of the hydraulic system.
WARNING
