TM 10-3930-671-24 10.2. Hydraulic System Relief Pressure Check & Adjustment Relief Pressure Check and Adjustment Procedure ............................................................... F-455 Relief Pressure Setting Check .............................................................................................. F-455 Hydraulic System Relief Pressure Specifications.................................................................. F-456 Relief Pressure Adjustment................................................................................................... F-456 Relief Pressure Check and Adjustment Procedure Following   is   the   general   procedure   for   checking   an setting    main    hydraulic    valve    lift    and    auxiliary    relief pressure, for the GPX 25 E truck. Hydraulic system relief pressure setting may be checked using  with  a  conventional  pressure  gauge  with  suitable pressure range calibration.  A gauge with capacity range of    0    to    4000    psi    (0    to    27580    kPa)    mini    mum    is recommended. NOTE To perform this service procedure, It is recommended that you first: • Park  truck  on  a  level  surface  and  fully lower the upright. • Put blocks under the upright rails and • Raise the drive wheels off the floor. • Return   all   controls   to   neutral,   apply parking brake, and turn key switch OFF, except as directed. WARNING Do  not  use  your  hands  to  check  for hydraulic   leakage.      Use   a   piece   of cardboard   or   paper   to   search   for leaks.  Escaping fluid under pressure can     penetrate     the     skin     causing serious    injury.        Relieve    pressure before    disconnecting    hydraulic    or other  lines.    Tighten  all  connections before    applying    pressure.        Keep hands and body away from pin holes and nozzles  which eject  fluids  under high pressure.  If any fluid is injected into  the  skin,  it  must  be  surgically removed   within   a   few   hours   by   a doctor familiar with this type injury or gangrene may result. Relief Pressure Setting Check 1. Open the engine compartment side door (RH or LH door, as noted later) and raise the seat deck. Be    sure    the    seat    deck    support    is    securely latched. 2. The     diagnostic     check     port     quick-disconnect fitting   (with   cap)   for   making   hydraulic   system pressure   checks   is   located   on   the   right-hand side   of   the   main   hydraulic   valve.      See   notice below. 3. Remove the cap and connect pressure gauge to the diagnostic check port fitting on the valve. 4. Start  the  engine  and  let  it  warm  up  until  it  runs smoothly. F-455