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1974 Case 580B Hydraulic Power to Backhoe

aross · 2025-05-27 20:35

Hey folks, second post here. I have finally been able to put my new to me 580B to work pulling some small stumps. Right off the bat I noticed the lack of power to the backhoe. It's not terrible but in comparison to my old 530ck I would say it is lacking. Plenty of power to the loader, outriggers lift the backhoe just fine, however oddly when I retract the outriggers back up they seem to bog down the motor a fair bit which I also never noticed on the 530. Fluids are topped off with the hoe in transport mode and filter has been replaced. I am scanning the forums here to gather info in order to test hydraulic pressure. In the meantime, I used the advice from @alrman who commented on another post about checking the o rings on the power beyond fitting. As you can tell the o ring has seen better days, not saying this will be my problem but it certainly needed to be replaced. I am going to order new o rings and get set up for pressure testing, in the mean time I will take any thoughts or advice from the professionals here!

Replies8
  1. #1HarleyHappy2025-05-28 07:22

    On my Case, the stabilizers almost stall the machine at idle, always has. For some reason, the stabilizers almost stall the machine when retracting but nothing else.

  2. #21978case2025-05-28 09:14

    Takes more HP to overcome the lock check valve when retracting or raising the stabilizers.

  3. #31978case2025-05-28 09:18

    I bet you need to replace the o-rings on the load check valves in the backhoe control valve.

  4. #4stinky642025-05-28 09:53

    Ding, ding, ding, you may have a winner. An inexpensive quick fix would be awesome. Did you order oem o-ring or going generic? An improper ring that still leaks could have you chasing your tail. Don't know about your B but my C has a pipe thread port, left side of loader control valve (look for round metal "plug" inside cab) for pressure test. 3000 lb. gauge plumbed in with a length of appropriate hydraulic line works great. Just don't leave test line attached forever. Neighbor found out the hard way, when old line he was using blew inside cab there was nowhere to run.

  5. #5aross2025-05-28 18:29

    Thanks for the advice, not familiar with those , I will have to do my research.

  6. #6aross2025-05-28 19:01

    I always try to go OEM Stinky. The two o rings on the beyond power fitting are part #’s 218-5010 and L32680. Neither of them appear to be available on the Case parts website however the replacement part #s are #167268 and #271913

  7. #7HarleyHappy2025-05-29 09:27

    Case and their very expensive and weird sizes of O-rings. lol

  8. #8stinky642025-05-29 17:52

    First set of #'s are same p/n's for o-rings on '76 C so test port may be same location as well. When I replaced mine ,they came from the pricey mother ship. Hopefully you don't have to rebuild backhoe control valve, there's a bunch of o-rings in that monster that they're particularly proud of.