Procedure for Steering and Lift/Lower Gear Pump Flow Test
Output from the steering and lift/lower gear pump sec- tion is equally divided by a proportional valve to provide flow to the steering circuit and the lift circuit. To test gear pump flow, testing of both steering and lift/lower circuits is required. Total gear pump flow is the combined flow from the two circuits.
1.Make sure hydraulic oil is at normal operating tem- perature by operating the machine for approximately 10 minutes. Make sure the hydraulic tank is full.
2.Park machine on a level surface with the cutting deck lowered and off. Make sure engine is off and the parking brake is engaged. Raise seat.
CAUTION
Prevent personal injury and/or damage to equip- ment. Read all WARNINGS, CAUTIONS and Pre- cautions for Hydraulic Testing at the beginning of this section.
IMPORTANT: Make sure that the oil flow indicator arrow on the flow gauge is showing that the oil will flow from the pump section, through the tester and into the hydraulic hose.
3.With the engine off and cutting deck lowered, discon- nect the hydraulic hose from the 90o fitting in the third gear pump section which supplies the steering and lift/ lower circuits (Fig. 43).
4.Install tester in series between the fitting and the dis- connected hose. Make sure the tester flow control valve is OPEN.
IMPORTANT: The pump is a positive displacement type. If pump flow is completely restricted or stopped, damage to the pump, tester or other com- ponents could occur.
5.Start the engine and move throttle to full speed (2870 RPM). DO NOT engage the cutting deck.
6.While watching pressure gauges, slowly close flow control valve until 1000 PSI (69 bar) is obtained on gauge. Verify engine speed continues to be 2870 RPM.
GAUGE READING TO BE: Flow approximately 7 GPM (26.3 LPM) at 1000 PSI (69 bar).
7.Stop engine and record test results.
8.If a pressure of 1000 PSI (69 bar) could not be ob- tained or flow is lower than 6 GPM (22.3 LPM) (85% of expected flow), check for restriction in pump intake line. If intake line is not restricted, consider that gear pump is worn or damaged.
9.When testing is complete, remove tester and recon- nect hose to pump fitting.
2 |
3 |
4 |
1 |
Figure 43
1. | Gear pump | 3. | Steering/lift hose |
2. | Fan drive manifold | 4. | 90o fitting |
Hydraulic System
Groundsmaster | Page 4 | Hydraulic System |
