Heavy Equipment Forums Heavy Equipment Community

Cat 312 hydraulic power loss

R Glover ยท 2012-08-24 07:56

Hey Guys, I would really appreciate some help on this. I have a 1993 Cat 312 that I use as mostly a farm unit. I was doing some low power dirt work & the hydraulic's pretty much shut down, I have about 5% hydraulic's. The 1st thing that I did was to change the tank & spin on filters, this did not do any good. I cut open both filters & no metal (Thank God for that). I am thinking ma-by a stomped up valve or regulator some where. Thought I would ask you guys before I called a Cat. I just got laid off & really don't have the $$$ for a visit from those guys. Any thoughts on this problem would be much appreciated. I will post the fix, if I ever figure it out. Thanks, Rube

Replies13
  1. #1josh2012-08-24 14:21

    could be broken drive on hydraulic pump

  2. #2Permafrost-ed2012-08-24 20:30

    Is the engine bogging down?......Fuel filter?

  3. #3R Glover2012-08-24 23:32

    No, the engine is not loosing any power.

  4. #4Per Eriksson2012-08-25 16:38

    is it both slow and weak or just weak?

  5. #5R Glover2012-08-25 21:48

    slow and weak

  6. #6kbeen2012-08-26 00:01

    is the travel circuit slow and weak as well. it has a different relief valve than the other circuits ?

  7. #7R Glover2012-08-27 22:30

    Yeah, everything pretty much is weak.

  8. #8kbeen2012-08-28 09:51

    you might want to start by checking the pilot pressure. this is the pressure it uses to move the spool valves to send the oil to the circuits. if is low enough you would not be moving the valve enough and could cause slow and weak systems. just a good place to start.

  9. #9wilson302012-09-01 22:53

    you also check the main pilot relief valve,it could be broken spring or o ring...

  10. #10R Glover2012-09-03 13:03

    The spring & O-Ring are both in good shape. Guess I'll find a gauge & check out the pressures. Any other ideas for a simple fix?

  11. #11kbeen2012-09-05 09:06

    R Glover have you tried operating the machine in the manual mode setting. this would eliminate the computer. are you familiar with the toggle switches inside the cab to change it from auto mode to manual mode and the other switch is to throttle up the engine. see how it acts in that mode.

  12. #12R Glover2012-09-05 09:13

    Yes sir, The turntable will swing around very slow, the bucket will curl very slow & the stick will push in & out very slow all on speed 10 at power level III. The boom will not raise at all & it will not track. All in manual mode.

  13. #13wilson302012-09-08 09:18

    can you please check the main pump..i think the main pump is weak?