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Case 450 dozer 6way blade won’t stay elevated

304thomas55 ยท 2021-10-28 21:16

I've developed a problem with 6way blade. While traveling the blade won't stay up. Suspect there's and issue with control valve. There's a lot of slop in linkage , but I believe it's internal. Would anyone have a diagram of control valve ?

Replies8
  1. #1Tinkerer2021-10-29 07:19

    Thanks to the good people at MinnPar this a link to the complete service manual. https://cdn.minnpar.com/partbooks/CASE (CNH) MANUALS/CNH (CASE) CRAWLER DOZER MANUALS/CASE CRAWLER MODEL 450 SERVICE MANUAL.pdf Your problem could be leaking piston seals in the blade lift cylinders.

  2. #2304thomas552021-10-29 07:55

    Thanks Tinkerer

  3. #3skyking12021-10-29 13:29

    yes I would suspect that as much as the valve. One leaky cylinder will do the trick. It will bypass for the whole blade lift circuit.

  4. #4304thomas552021-10-29 21:28

    Is there away of knowing which seal or just inspect both ?

  5. #5skyking12021-10-29 21:31

    I've not tried this, but it seems to me you could block up the blade, pull a pin, then block the lines on one cylinder. if that cylinder falls down overnight you know that cylinder is bypassing at the piston.

  6. #6304thomas552021-10-29 21:40

    That might work. I'll give it a try and report back

  7. #7Tinkerer2021-10-30 07:18

    If you are capable of repacking the cylinders yourself the seal kits are not very expensive. If you were to reseal both of them you would then have 2 cylinders that should give you many years of service. That would accomplish two things, one would be eliminate the problem or 2 --> indicate a problem in the control valve. You can buy high quality kits at a decent price here ---> http://e-backhoeparts.com/

  8. #8skyking12021-10-30 10:34

    that is true!