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Sauer Danfoss series 90 problem

domagoj.rajn ยท 2026-06-06 04:45

Hi, I have Sauer Danfoss series 90, 130cc pump and motor on Claas Lexion 570 combine and I have a problem with that system. At maximum displacment (at full engine throttle and max pump flow) the pump looses charge pressure and combine looses drive. If I reduce displacment with forward/reverse joystick pump regains charge pressure and drive. Also when going in reverse or braking charge pressure spikes very high. The combine has no power loss if I don't use max pump displacment. The pump was rebuilt last season because it broke down so we put new charge pump and cylinder block but it didn't make any difference. Did anyone have similar problem or any experieance with that system?

Replies3
  1. #1LN Pipeline2026-06-06 21:49

    Have you tried swapping multi-function valves to see if problem changes to reverse?

  2. #2domagoj.rajn2026-06-07 05:40

    I will try that, thanks.

  3. #3domagoj.rajn2026-06-09 13:57

    We did some testing with Claas mechanic today and turns out I measured charge pressure wrong. Charge pressure is fine but at max flow we are experiencing pressure loss at A and B lines. Line A (forward) drops to 7 bar and line B (reverse) drops to 4 bar. We also tested max pressure and got good results. We tried swapping multi-function valves but the problem remained the same.