Procedure for Lift/Lower Circuit Relief Pressure Test
NOTE: Before attempting to check or adjust lift pres- sure, make sure that counterbalance pressure is cor- rectly adjusted.
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.
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.
3.Raise seat to gain access to hydraulic test fitting. Connect a 5,000 PSI (345 bar) gauge to lift circuit test port (Fig. 41). Route gauge hose to allow seat to be safe- ly lowered.
4.After installing pressure gauge, start engine and run at idle speed. Check for hydraulic leakage and correct before proceeding with test.
5.Sit on the seat and operate the engine at full speed (2870 RPM).
6.While sitting on the seat, pull lift lever back to raise the cutting deck. Momentarily hold the lever with the lift cylinder fully retracted (deck fully raised) while looking at the gauge.
GAUGE READING TO BE 2500 to 2550 PSI (173 to
175bar).
7.Stop the engine and record test results.
8.If pressure is too high, adjust relief valve in lift control valve by rotating counterclockwise (Figure 42). If pres- sure is too low, check for restriction in pump intake line. Check the lift cylinder for internal leakage. If cylinder is not leaking, adjust the relief valve by rotating clockwise. If pressure is still too low, pump or lift cylinder(s) should be suspected of wear, damage or inefficiency.
9.When testing is completed, disconnect pressure gauge from test port.
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2 |
4 |
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Figure 41
1. | Fan drive manifold | 3. | Lift control valve |
2. | Lift circuit test port | 4. | Relief valve |
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3
4 
5
1
| Figure 42 |
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1. | Control valve assembly | 4. | Spring |
2. | Relief valve assembly | 5. | Poppet |
3. | Washers |
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Hydraulic System
Groundsmaster | Page 4 | Hydraulic System |
