Heavy Equipment Forums Heavy Equipment Community

Bobcat 331 drive motor

Iddee ยท 2022-07-26 11:54

My 331 right track quit moving. Move the lever either forward or back and the valve moves in and out as it should. I removed the track motor cover and removed the small line under the two large lines. When the engine was started, full pressure hyd. fluid came out of the motor, without engaging the valve. Does this indicate the motor or valve is bad?

Replies9
  1. #1uffex2022-07-27 03:52

    Good day If you pressure yest the two main lines and these meet specifications you are safe to condem the motor. kind regards Uffex

  2. #2Iddee2022-07-27 04:48

    Should the two main lines have pressure when the control valve is not activated?

  3. #3uffex2022-07-27 04:58

    Good day According to my schematic, both lines have open centre spools, which will mean you will have tank pressure as default. Kind regards Uffex

  4. #4Iddee2022-07-27 05:04

    Then that means if I have pressure on both lines and pressure coming out of the motor at the small line port, with the valve not activated, then the motor is bad. Is that correct?

  5. #5uffex2022-07-27 08:07

    Good Day You have four lines to each motor - two main lines - one smaller which is case drain & a fourth which changes the speed / displacement. If you remove the two main lines, plug one with a pressure able, plug the remaining line with a gauge. Drive that motor in the direction of the gauge, you should see working pressure > switch the line plug and gauge check once more. If both pressures are good, the issue is with the motor - shock valves and sundries. I would suggest pulling the motor down on the bench if this is the case. I hope this helps out. Kind regards Uffex

  6. #6Iddee2022-07-27 09:19

    Thanks for the help. What if you have pressure on the main lines as soon as you start the diesel engine, but don't activate the valve.xxl.

  7. #7uffex2022-07-27 11:25

    Good day If you have main pressure in those lines, the fault is at the main valve chest. May I suggest you take one step at a time. Kind regards Uffex

  8. #8Iddee2022-07-27 12:03

    That's what I was afraid of. I can remove the motor, but I have no idea how to get the valve out. I am 77 tears old and bought this as a play toy. I have been a mechanic all my life, but have never worked on construction equipment. Thank you for your help. I think it's time to call in a service man..

  9. #9uffex2022-07-27 12:18

    Good day Iddee 77 you come from a good decade as do I, dont be to nevouse only put together by humans. Take care Uffex