TM 5-3895-382-24 Testing and Adjusting Troubleshooting During  a  diagnosis  of  the  hydraulic  system,  remember  that correct    oil    flow    and    pressure    are    necessary    for    correct operation.  The output of the pump (oil flow) increases    with    an    increase    in    engine    speed    (rpm)    and decreases   when   engine   speed   (rpm)   is   decreased.      Oil pressure is caused by resistance to the flow of oil. The   4C-4892   ORFS   Fittings   Group   can   be   used   to   make pressure tests on the vibratory system.  Before any tests are made,   visually   inspect   the   complete   hydraulic   system   for leakage of oil and for parts that are damaged.  For some of the tests a magnet and a mm (in) measuring rule are usable tools. When any test is made of the vibratory system, the hydraulic oil  must  be  at  the  normal  temperature  for  operation  (38C [100F]). Sudden movement of the machine or release of oil under pressure   can   cause   injury   to   persons   on   or   near   the machine.    To  prevent  possible  injury,  do  the  procedure that   follows   before   testing   and   adjusting   the   vibratory system. 1. Move   the   machine   to   a   smooth   horizontal   location. Move away from working machines and personnel. 2. Permit  only  one  operator  on  the  machine.    Keep  all other personnel either away from the machine or in view of the operator. 3. Activate the parking brake. 4. Stop the engine. 5. Move   the   hydraulic   control   lever   to   all   positions   to release any pressure in the hydraulic system. 6. Carefully loosen the filler cap on the hydraulic oil tank. 7. Make sure all hydraulic pressure is released before any fitting,    hose    or    component    is    loosened,    tightened, removed or adjusted. Visual Checks A visual inspection of the vibratory system and its components is the first step when a diagnosis of a problem is made.  Then check   the   operation   of   the   machine.      Finally,   check   the vibratory    system    with    gauges.        Perform    the    following inspections. Do  not  check  for  leaks  with  your  hands.    Pin  hole  (very small)  leaks  can  result  in  a  high  velocity  oil  stream  that will be invisible close to the hose.  This oil can penetrate the  skin  and  cause  personal  injury.    Use  cardboard  or paper to locate pin hole leaks. 1. Check the oil level of the hydraulic oil tank. 2. Look for air in the oil that is in the hydraulic oil tank.  Do this  immediately  after  the  machine  is  stopped.    Use  a clear bottle or container to get a sample of the oil.  Look for air bubbles in the oil that is in the bottle. 3. Check all oil lines, hoses and connections for leaks and damage.  Look for oil on the ground under the machine. 4. Remove   and   check   the   hydraulic   filter   element   for foreign materials. a. Bronze-colored  particles  give  an  indication  of  pump port plate failure. b. Shiny  steel  particles  give  an  indication  of  pump  or motor piston failure or motor cam deterioration. c. Rubber particles give an indication of a seal or hose failure. d. Aluminum   particles   give   an   indication   of   steering pump failure. Checks During Operation With the engine running, operate the machine in each direction and from low to high speed.  Make note of all noises that are not  normal  and  find  their  sources.    If  the  operation  is  not correct, refer to the list of problems and probable causes. The checks during operation can be used to find leakage in the system.  They can also be used to find a bad valve, pump or motor.  Vibratory frequency can be used to check the condition of the vibratory motor and the Pump. 13-30