TM 5-3895-383-24 Pump Servo Neutral - Adjust SMCS Code:  5261-025 Fixed Frequency and Variable Frequency Table 9 Required Tools Part Number Description Qty 6V-7830 Tetragauge 2 6V-8628 Elbow 2 4J-5477 O-Ring Seal 2 3J-7354 O-Ring Seal 2 9X2348 Hose 36 inches 9X-3757 Coupling 2 Personal injury or death can result from sudden machine movement. Sudden  movement  of  the  machine  can  cause  injury  to persons on or near the machine. To prevent injury or death, make sure that the area around the machine is clear of personnel and obstructions before operating the machine. NOTICE Care  must  be  taken  to  ensure  that  fluids  are  contained during  performance  of  inspection,  maintenance,  testing, adjusting  and  repair  of  the  machine.    Be  prepared  to collect  the  fluid  with  suitable  containers  before  opening any    compartment    or    disassembling    any    component containing fluids. Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide", for tools and supplies suitable to collect and contain fluids in Caterpillar machines. Dispose  of  all  fluids  according  to  local  regulations  and mandates. NOTE:    Perform the Charge Relief Valve - Test and Adjust and the Main Relief Valve - Test and Adjust before conducting the Pump Servo Neutral - Adjust. Illustration 55 Vibratory Pump (1)  Servo.    (2)  Servo  Ports.    (3)  Locknut.    (4)  Servo  valve neutral adjustment screw.  (5) Main relief valve test ports. 1. Make sure that the parking brake is applied.  Make sure that the propel control lever is in neutral. 2. Disconnect   the   electrical   connection   for   the   vibratory pump control. 3. Remove the plugs from servo ports (2).  Install the  3J- 7354 O-Ring Seals on the 6V-8628 Elbows.  Install the elbows  in  servo  ports  (2),  and  install  the   4J-5477  O- Ring Seals in the elbows. 4. Fabricate a hose assembly by using the 9X-2348 Hose and  9X-3757  Coupling.    Connect  the  hose  assembly between  the  elbows  that  were  installed  in  the  servo ports. 5. Install the two 6V-7830 Tetragauges on the main relief valve test ports (5). 6. Start and run the engine at high idle. 7. Read pressure readings on the two 6V-7830 Tetragauges.        The    pressure    readings    should    be identical. 8. If the pressure readings are not identical, loosen locknut (3) so that the neutral position of the servo piston may be adjusted.  Use an allen wrench in order to turn servo valve  neutral  adjustment  screw  (4).    Turn  the  screw clockwise   or   counterclockwise   in   order   to   adjust   the mechanical center of the servo valve.  The pressures on the   two   6V-7830   Tetragauges   should   change.      Turn servo   valve   neutral   adjustment   screw   (4)   until   the pressure  readings  on  main  relief  valve  test  ports  are identical.  Tighten locknut (3). 9. Stop the engine. Remove the two 6V-7830 Tetragauges. 10. Remove    the    hose    assembly    and    the    elbows    that connect servo ports (2), and install the two plugs. 11-51