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D8H ripper wont stay up, oil?

Discussion in 'Dozers' started by D8HCattle, Jun 25, 2021.

  1. D8HCattle

    D8HCattle Member

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    Rebuilt/sealed all four ripper cylinders, adjusted the linkage that the (4 way) accessory lever attaches to, and flushed all of the oil, tank included with SAE 10 cat equivalent. Now the ripper droops and needs to be lifted every other minute. Im leaning more toward oil or linkage. The cylinder tested good and did not droop prior to linkage adjustment or oil change. I have a hard time thinking it was the linkage because all i did was adjust the ball socket at the bottom of the lever so it would be centered in the cutout templet to move the ripper. Or maybe that is the problem, hoping some of yall can weigh in om that but the mechanical engineer in me say its not that. So how bout the oil? Book say use SAE 40 for temps about 90. Im in main… yes it does get above 90 but to that much. Any help ladies and gents would be appreciated. Thank you for your time!
     
  2. Bluox

    Bluox Senior Member

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    Logic says look at the last thing you fixed before the problem started so redo linkage .
    Oil is 10w up to 130 degrees'.
    Did you check cylinders since this problem started?
    Bob
     
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  3. Vetech63

    Vetech63 Senior Member

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    Its not an oil problem, its a leakage in the circuit problem.
     
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  4. Tinkerer

    Tinkerer Senior Member

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    Welcome to HEF, D8HCattle !
     
  5. D8HCattle

    D8HCattle Member

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    Thank you all!

    I’ll reset the linkage and go from there. Guess there must be some worn out ball sockets under the tank. I am a little baffled why that would do it but it is an easy fix. There is no movement on that linkage unless i move the lever and it is a simple pivot set up. Then again cat engineers are a lot smarter than me. Ill update.
     
  6. D8HCattle

    D8HCattle Member

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    thank you! Ill reset And go from there. I did linkage and oil at the same time, so thats why i was at least considering it
     
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  7. Nige

    Nige Senior Member

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    If I may ask, what prompted you to rebuild all four ripper cylinders.?
     
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  8. chidog

    chidog Well-Known Member

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    Could be one of the lift cylinder piston seal is leaking too. Maybe cut a seal or?
     
  9. nicky 68a

    nicky 68a Senior Member

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    As stated above,I wonder why you went in there in the first place?I guess it wasn’t for the fun of it.
     
  10. epirbalex

    epirbalex Senior Member

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    Here's a link that may help you
    https://www.machinerylubrication.com/Read/1119/hydraulic-cylinder-drift
    I think you may have damaged a relief valve or assembled it incorrectly on one of the pistons . I've got into the habit of taking photos when I disassemble gear , easy to go back and check . Helps when you are not able to keep working on a job . Of course, if the controls are not hooked up right there will be flow . That should be where you start to troubleshoot
     
  11. D8HCattle

    D8HCattle Member

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    ripper was off machine for a while, due to bad seals. No sense putting it back together with only the insurance of some cylinders being good for a while, so i had all rebuilt. The oil flush should seem self explanatory. The linkage adjustment was to take slop out. I figured thats one reason why there is linkage adjustment. Some suspect its the linkage so that what ill undue and go from there.
     
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  12. D8HCattle

    D8HCattle Member

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    thank you for the link!.. i do the same. Took pictures, label everything with permanent marker and numbered tape. Not my first rodeo, made that mistake long ago, don't need that headache again.
     
  13. Nige

    Nige Senior Member

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    Do you have (or can you get hold of) an infra-red temp gun.?
    If so raise the ripper fully up at just off Low Idle RPM and hold the lever in the raise position. Point the temp gun at the approximate position of the piston in the cylinder, first on one cylinder, then the other. Keep switching back and forth from one cylinder to the other. Do you see a significant temp rise.? If you do then the piston seals on that cylinder are suspect. If you don't then you need to be looking elsewhere.
     
  14. Puffie40

    Puffie40 Well-Known Member

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    Sae10w seems like an awfully thin hydraulic oil to use. You sure that is what the manual recommends?
     
  15. Nige

    Nige Senior Member

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    SAE10W has been pretty much the standard hydraulic oil with just a few specific exceptions for Cat machines since the year Dot.
    Below the lube chart for the D8H

    upload_2021-6-30_3-16-13.png
     
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  16. Bluox

    Bluox Senior Member

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    That chart is for a really late 8Hs and 8Ks
    Bob
     
  17. Puffie40

    Puffie40 Well-Known Member

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    Huh - that's interesting. In my area SAE32 seems to be the standard go-to for most hydraulic applications, but if thats what the manual wants, then it should be fine.

    Cyilinders leaking down usually means either your piston packings are worn, or something is wrong with the valve spool.

    You say you rebuilt the cyilinders. Did that include the piston packings? Nige's test will tell you if the cyilinders are at fault, or if you need to move up to your valve bank for the next round of troubleshooting.
     
  18. Nige

    Nige Senior Member

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    I think you’ll find it’s not SAE32 you are referring to but ISO32. They are two different viscosity systems and ISO32 is the equivalent in viscosity to an SAE10W.
     
  19. chidog

    chidog Well-Known Member

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