Lifting Arms
393
Adjusting the Arm Vane Pump Relief Valve
Usually, there is no arm vane pump relief valve on an E
XPERT
™. However, if your E
XPERT
™ vehicle is
equipped with such a valve, it would be located on the front of the pump.
Tighten the relief valve completely on the pump.
The arm (retract/extend) and gripper (up/down) operating pressures are the same as the main relief
valve. Table 1 lists the operating pressure and cycle time for each arm function. No adjustments are
required for these functions. Only “gripper close” requires proper adjustment to prevent crushing
roller carts. See
Lubrication Chart and Hydraulic Schematic
on page 415 to adjust the gripper load
sense relief valve.
For more information, see
Adjusting Proportional Valve Pressure
Bypassing a Dump Valve for Diagnostic Purposes
This procedure explains how to bypass the arm dump valve off of a front-mounted pump for an
E
XPERT
™ side loader.
When arm cycle times and pressures are not able to be achieved, typically there are 2 components
that cause this: the dump (or recirculation) valve or the pump. The first step in troubleshooting is to
verify that the electrical system is operating correctly. If the dump valve is receiving proper power and
ground, causing the coil to magnetize, then we can continue with bypassing the arm dump valve.
Next step is to remove the dump valve all together and verify operation. If the arm operates with the
correct cycle times and pressures, then we can conclude that the dump valve is faulty and needs to be
replaced.
However, should the arm continue to have slow cycle times and low pressures, then the fault more
than likely is with the pump.
To bypass the arm pump dump valve on a front-mounted pump, apply this procedure:
1.
The truck should be off and locked out/tagged out following all required procedures.
2.
Relieve the air pressure from the hydraulic tank.
3.
Close the ball valve (or shut-off valve) on the suction line, which is on the right side of the
hydraulic tank.
Table 1
Arm operating pressures and cycle times
Arm function
Pressure setting (psi)
Cycle time (sec.)
Extension/retraction
2000
2.8/4.2
Gripper up
2000
3.0
Gripper down
2000
3.0
Gripper close
1200
1.5
Gripper open
1200
1.8
Summary of Contents for EXPERT
Page 1: ...EXPERT TM MAINTENANCE MANUAL...
Page 2: ......
Page 3: ...EXPERT MAINTENANCE MANUAL...
Page 10: ...viii Table of Contents...
Page 18: ...8 Introduction...
Page 244: ...234 General Maintenance...
Page 251: ...Lubrication 241 Figure 4 11 Glass compartment lubrication chart optional...
Page 252: ...242 Lubrication Figure 4 12 EXPERT lubrication chart...
Page 264: ...254 Lubrication...
Page 320: ...310 Hydraulic System...
Page 357: ...Troubleshooting 349...
Page 358: ...350 Troubleshooting...
Page 386: ...378 Multiplexing...