H Y D R A U L I C  S Y S T E M TM   5-3805-258-24-1 T E S T I N G  A N D  A D J U S T I N G Lift, lower, dump and tilt back the bucket several times. 1. 2. 3. 4. Watch  the  cylinders  as  they  are  extended  and retracted.   Movement   must   be   smooth   and regular. Listen  for  noise  from  the  pump. Listen  for  the  sound  of  the  relief  valves.  They must  not  open  except  when  the  cylinders  are fully  extended  or  retracted,  when  the  bucket  is empty. Watch   the   operation   of   the   bucket   positioner and  lift  kickouts. The lift control lever has detents in the RAISE and FLOAT  positions. The  tilt  control  lever  has  a  detent  in  the  TILT BACK position (only when the bucket is between full dump  and  the  bucket  angle  to  dig). Lift And Tilt Cylinder Drift Tests The  drift  rates  will  change  with  different  condi- tions of the hydraulic components as well as with the operation,   the   type   of   bucket   (empty   or   loaded), hydraulic  oil  temperature,  etc. The values shown are for an empty bucket. Before measuring  drift  on  the  cylinder  rod,  the  cylinders must  be  extended  at  least  five  times.  Check  the  oil temperature. To  check  the  lift  circuit,  lift  the  bucket  to  maxi- mum height and move the control lever to the HOLD position.  Measure  the  distance  (and  check  the  time) that  the  cylinders  retract,  with  the  chart. NOTE:  The  drift  distances  in  the  charts  are  for  new machines. APPROXIMATE   LIFT  CYLINDER   DRIFT OIL 38    ~    3°C 49    f    3c’c 66    *    3°c TEMPERATURE (100    i    5°F) (120  f5°  F) (150   L   5°F) mm in. mm in. mm I in, L 1 1 Maximum    Drift 13.0 1 .51 13.0 .51 13.0 .51 Time   In Minutes 5.0 2,7 1.7 To  check  the  tilt  circuit,  lift  the  bucket  to  maxi- mum  height,  and  move  the  lift  control  lever  to  the HOLD   position.   Activate   the   tilt   circuit   until   the bucket is at the angle to dig (almost level) and move the tilt control lever to the HOLD position. Measure the  distance  (and  check  the  time)  that  the  cylinder retracts,  with  the  chart. I APPROXIMATE    TILT   CYLINDER   DRIFT OIL 38    ~    3°C 49    f    3°c 66    *    B“c TEMPERATURE (100    Y    5°F) (120  f5°  F) (150t5°  F) mm in. mm in. mm in. Maximum    Drift 19.0 .75 19.0 .75 19.0 .75 Time   In Minutes 5.0 2.7 1.7 1 I I If  the  cylinder  drift  is  too  much: 1.  Check  the  make-up  valves  in  the  lift  and  tilt control valve. 2. Check the condition of the valve spools in the lift and  tilt  control  valve. 3.  Check  the  piston  seals  in  the  cylinders. Attachment Cylinder Drift The  attachment  cylinders  will  drift  in  the  close  or lower direction because of an orifice (to the tank) in the   line   from   the   rod   end   of   the   attachment cylinders. Lift And Tilt Cylinder Speed Tests Start and run the engine at high idle rpm. Lift and lower the lift arms again and again to get an increase in  the  temperature  of  the  hydraulic  oil. The  oil  in  the  system  must  be  SAE  10  and  at  a temperature  of  65  ±  3°C  (150  ±  5°F)  to  get  accur- ate  test  results.  All  speed  tests  are  made  with  the engine at high idle. The speeds in the following chart are  those  of  machine  equipped  with  a  general  pur- pose  bucket. APPROXIMATE SPEED  IN TILT CYLINDER SPEED TEST SECONDS DUMP    (full    tilt    back-to-full dump,   bucket   at   maximum height,   empty   bucket) 2.0    *    0.5 If the travel times are not correct: 1. Check the pump efficiency. 2. Check the setting of the relief valves. 3.  Check  the  make-up  valves  in  the  lift  and  tilt control  valve. 4. Check the valve spools in the lift and tilt control valve. 5. Check the piston seals in the cylinders. 4-69