Test Procedures
1 Install the Hydraulic System Analyzer on the rod or cap side of the cylinders
2 Select
Run
and/or
Record
on the PC (see
"Recording Measurements to a File" on page 10
)
3 With the load valve fully open, the extension or retraction times can be set, verified and/or logged in the circuit Inches per
Minute = (231 × GPM) / SQ IN
4 Force can also be checked by checking the pressure when the cylinder is at the end of its stroke
Force = Pressure × Area
◊ If all components are in good operating condition, pressure and flow measurements should be the same as in the
Pump Test
◊ If a decrease in flow or pressure in any control valve position is noted, leakage is indicated
◊ If the decrease in flow is the same with the control valve(s) in all positions, it indicates the relief valve is at fault
OTE:
N
This can also indicate some other leak is present in the control valve, such as a defective casting, damaged seals, or
worn valve position detents, but always check the relief valve FIRST
◊ If the relief valve is operating normally, see Directional Control valve (DCV) Test
◊ A decrease in pressure at the cylinders full stroke could indicate worn piston seals
Hydrostatic Transmission Diagnostics
Install the Hydraulic System Analyzer into the system between the pump discharge port and the inlet of the hydraulic motor
PV
Flow (Bi-directional)
Reservoir
Case Drain
MF
Flo-Check
Figure 11: Hydrostatic transmission test
Pump
1 Open the Hydraulic System Analyzer loading valve fully to read maximum pump flow at zero pressure
2 Select
Run
and/or
Record
on the PC (see
"Recording Measurements to a File" on page 10
), then close the loading valve to
increase pressure from zero pressure to rated or maximum pump pressure to determine pump condition
3 The pump flow at rated pressure can now be checked against the pump manufacturer’s specifications A decrease in flow
from zero pressure to maximum pressure indicates a drop in volumetric efficiency
Motor Test No Load
1 Open the Hydraulic System Analyzer loading valve fully to read maximum pump flow at zero pressure
2 Select
Run
and/or
Record
on the PC (see
"Recording Measurements to a File" on page 10
)
3 Put one control valve in the forward operating position If there are multiple valves, only one control valve should be in an
operating position at any one time
4 Using a tachometer, run the motor with no load The flow and RPM should match the manufacturer’s specification A
decrease in RPM from the manufacturer's specifications indicates a loss of the motor's efficiency
Page 23
June 2022
TST-UM-02433-EN-02