Heavy Equipment Forums Heavy Equipment Community

Case 40XT control issues

josh1985 ยท 2017-10-14 18:58

Hey everyone, I have a Case 40XT that is having issues with the control. The machine jumps aggressively when trying to turn. Going straight doesn't seem to be an issue just turning. Is there anything specific about these case units that wears and causes this? Any tips and pointers about these case units would be appreciated as it's the first case I have worked on. Thanks in advance

Replies8
  1. #1alrman2017-10-14 19:39

    Welcome to HEF @josh1985 ! It could be possible that there could be something loose in the control arm areas of the tandem pumps. Also check the control arm return springs mounted to the servo spools for any breakages. If you have good rubber on your tyres & are trying to turn on dry concrete or bitumen, they will buck.....

  2. #2josh19852017-10-14 19:48

    Thanks, but the "buck" has a hesitation and the linkage was the first check. The rubber on the machine is roughly 20% remaining and im testing on gravel. I haven't noticed any deadspots going forward/reverse straight either.

  3. #3alrman2017-10-14 19:56

    I have seen the 1/2" nuts on the servos work loose & over time the slot on the short lever arm, where they engage the spool becomes worn, causing weird control functions. They also like to have at least, mid to 3/4 throttle range, you're not operating at low rpm?? Drive motor mounting bolts are tight? Drive chain tensions are good/even LH & RH?

  4. #4GaryHoff2017-10-15 12:35

    Also have a good look at your chains and sprockets. The rollers on the chains wear out, and sometimes break. If someone has had the servo spools out and put them in backwards, you will lose some feathering.

  5. #5josh19852017-10-16 10:13

    I have checked the drive chains and they do appear to be loose. Also LH side motor had 2 loose bolts. Does anyone know the deflection specs for the drive chains?

  6. #6josh19852017-10-16 15:19

    I adjusted the chains and tightened the motor. This helped but did not solve the problem. It feels as if one is swinging a bucket in a circular motion with the bucket having water in it as a weight. This happens only turning in one direction.

  7. #7GaryHoff2017-10-17 22:19

    Spec for the drive chains is 1/2" - 2" deflection. When going forwards, does the machine keep traveling a bit after you let go of the controls? If you slightly feather the other side when turning, does the "buck" stop?

  8. #8josh19852017-10-17 22:26

    Question 1 - No Question 2 - No