Procedure for Traction Circuit Charge Pressure Test
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 and support operator 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.
3.Connect a 1000 PSI (70 bar) gauge onto charge pressure test port (Fig. 21) under operator seat.
4.After installing pressure gauge, start engine and run at idle speed. Check for hydraulic leakage and correct before proceeding with test.
5.Operate the engine at full engine speed (2870 RPM) with no load on the hydraulic system.
GAUGE READING TO BE 200 to 300 PSI (13.8 to
20.6bar).
6.Stop engine and record test results.
7.If there is no pressure, or pressure is low, check for restriction in pump intake line. Also, inspect charge relief valve located in filter manifold (see Hydraulic Manifold Service: Filter Manifold in the Service and Repairs sec- tion of this chapter). If necessary, check for internal dam- age or worn parts in gear pump.
8.Also, with the pressure gauge still connected to the charge pressure test port, take a gauge reading while operating the machine in forward and reverse. Start the engine and put throttle at full engine speed (2870 RPM). Apply the brakes and push the traction pedal forward, then reverse.
GAUGE READING TO BE 200 to 300 PSI (13.8 to
20.6bar).
9.If charge pressure is good under no load, but consis- tently drops below specification when under traction load, the piston (traction) pump and/or traction motor(s) should be suspected of wear and inefficiency. When the pump and/or traction motor(s) are worn or damaged, the charge pump is not able to keep up with internal leakage in traction circuit components.
10.When testing is completed, disconnect pressure gauge from test port.
1 |
2 |
Figure 21
1. Charge pressure port | 2. Filter manifold |
Hydraulic System
Groundsmaster | Page 4 | Hydraulic System |
