TM    5-3805-258-24-1 T R O U B L E S H O O T I N G PROBLEM: Machine turns too slow in both directions. PROBABLE CAUSE: 1. Springs for flow control valve are not adjusted correctly. 2. Not enough flow from primary steering pump section. 3. Main control spool does not move all the way. PROBLEM: Machine turns too slow in one direction. PROBABLE CAUSE: 1. Flow balance adjustment of main control spool is not correct. (See   Steering   Time   Check   in   Testing   and Adjusting). PROBLEM: Machine turns correctly when roading (mov- ing), but is slow in both directions when the machine   turns   against   a   load   (high resistance). PROBABLE CAUSE: 1. Leakage past relief valve seat or seals. 2.  Leakage  past  both  ball  resolver  seats. 3. The fit of the flow control valve in the bore is not correct. PROBLEM: Machine turns correctly when roading (mov- ing),  but  is  slow  in  one  direction  when  the machine   turns   against   a   load   (high resistance). PROBABLE CAUSE: 1. Right turn: leakage past upper ball resolver seat or seal. 2. Left turn: leakage past lower ball resolver seat or seal. PROBLEM: Machine does not turn when steering wheel is turned. PROBABLE CAUSE: 1. Flow control valve will not move from the open position. 2. A defect in the pilot relief valve or seat. 3. Failure of the seal around the seat for the pilot relief valve at higher system pressures. NOTE: Some steering “slip” is normal. See Steering Slip  Check  in  Testing  and  Adjusting. S  T  E  E  R  I  N  G   S  Y  S  T  E M PROBLEM: Machine turns by itself (operator does not turn the steering wheel). PROBABLE CAUSE: 1. 2. 3. *4. 5. Spool in steering valve does not return to neutral correctly. The mounting bolts for the steering control valve are  too  tight. The bolts are too tight for the end covers of the steering  control  valve. Manufacturing  tolerances  on  spool  in  steering control valve do not permit spool to go back to neutral. Steering wheel turns without operator turning it. a. Foreign material causes sleeve valves in HMU to stick. b.  HMU  centering  (leaf)  springs  are  broken  or damaged. *This can be corrected on some machines by turning the spool in steering control valve around in its bore (turn end for end). To do this, the spring, retainer, and shims must be installed on the opposite end of the spool. An adjustment may be necessary for the steering times. PROBLEM: Machine turns too fast to make small steering corrections when the machine moves at fast speeds. PROBABLE CAUSE: 1. 2. 3. Flow control valve adjustment is not correct. (See   Steering   Time   Check   in   Testing   and Adjusting). Main control spool does not move freely. Metering orifices on main control spool are filled with   foreign   material   or   were   not   drilled correctly. PROBLEM: Pump makes noise and the steering cylinder rod does not move smoothly. PROBABLE CAUSE: 1. 2. 3. 4. 5. 6. Air  in  the  steering  hydraulic  circuit. The pump has too much wear. Loose connection of the oil line on the inlet side of the pump. The viscosity of the oil is wrong. The relief valve opens at low oil pressure. The oil level in the tank is low. 4-100