Cub Cadet U-Channel Beam Style User Manual
Page 34
3b.
Continue closing the needle valve until the
pressure gauge reads 2,000 PSI. Record
the following:
Engine RPM
Flow meter reading
Pressure reading
Flow from the pressure mode flow capacities
chart.
•
Open the needle valve to relieve the pres-
sure and turn off the engine
Interpreting the results:
•
A significant difference between the specified and observed pump performance indicates a bad pump.
4.
Control valve test
Relieve the hydraulic pressure from the system.
Install the test gauges between the control valve
and the cylinder.
Warm-up the fluid and purge air from the hydraulic
system.
Control returns to the stop position when released
from the extend position.
Control stays in the retract position until the piston
is fully retracted.
4a.
Extend the cylinder fully using the log split-
ter control valve.
•
As the ram reaches the end of its travel,
pressure will build until the relief valve
opens. Record the following:
Maximum pressure reached.
Relief valve setting from the relief valve settings chart.
NOTE: The relief valve is not adjustable. If the reading does not match what is listed in the chart, replace the
valve. A high reading is a bad control valve. A low reading could be a bad valve or a cylinder leaking
internally.
5.
Cylinder blow-by test
5a.
Hold the control valve until the ram stops moving.
Record the flow reading.
NOTE: Fluid movement when the ram is fully extended indicates that the piston seals are not working.
NOTE: Seal kits are available to repair leaking cylinders. If the cylinder has mechanical damage it must be
replaced.
Pressure Mode Flow Capacities
Pump
Tonnage
GPM/LPM
+ 0.5 GPM
718-04127
21,25 and 27
1.5 (5.6 lpm)
718-04729
27 ton HP
pump
3 (11 lpm)
718-04128
33
3 (11 lpm)
NOTE: If the readings are low, inspect the engine cou-
pler, the keys, set screws and the spider before con-
demning the pump.
Relief Valve Settings
Valve part
number
Tonnage
Relief valve
setting
+100 PSI
718-04706
27 and 33
3400 PSI
(234 bar)
718-04739
21
2700 PSI
(186 bar)
718-04740
25
3200 PSI
(221 bar)