Page 2 of 3 FirstFirst 123 LastLast
Results 11 to 20 of 21
  1. #11
    Elite Member
    Join Date
    Jan 2011
    Posts
    2,509
    Location
    Fanning Springs, Gilchirst County, North-Central Florida
    Tractor
    Kubota Tractor Loader L3560 HST 37-hp / 5,400 pounds

    Default Re: 3 ph drifts down

    Quote Originally Posted by 600rider View Post
    Jeff9366, The tractor is stored in a heated garage, has about 600hrs. on it, hasn't had the filter or fluid changed since what was recommended after the initial break-in period.
    You do not actually say you have checked the hydraulic fluid level. Have you? It is time to change the hydraulic fluid and filter after 600 hours and 8+ years, that is for sure.

  2. #12
    Platinum Member 3v0's Avatar
    Join Date
    Jan 2013
    Posts
    520
    Location
    Oklahoma Pan Handle, United States
    Tractor
    Kubota BX2200

    Default Re: 3 ph drifts down

    Is anyone saying that changing hydraulic fluid might help leak down ? I can see this helping if the tractor has the wrong type fluid in it. Not so sure if you replace the fluid with the same type.

  3. #13
    Bronze Member ScottyChip's Avatar
    Join Date
    Jan 2008
    Posts
    92
    Location
    Newfoundland, Canada
    Tractor
    Kubota B7510

    Default Re: 3 ph drifts down

    Hi 600Rider, my kubota 7510 is the same, the 3pt hitch drifts down, in my case it will drift down faster when the rpm's are at or just above idle and very slowly at 2000 or higher. It is a pain. I am considering the repair this summer, I think that Sd455dan in post #10 hit the nail on the head, the seals on the Hydraulic piston/lift arm are bad and need to be replaced. I am attaching an image from the parts manual I found showing the piston (#010) and the O ring (020) with Ring back up (030) are the parts I am going to need.
    The knob under the seat will not lock the 3pt in position if the seal is bad, the hydraulic fluid will bypass the control mechanism. Hope this helps.-b7510-hyd-piston-lift-arm
    Kubota B7510 HST, LA302 FEL, B2781 PTO snow blower, box blade, woods bh-6000 backhoe, a horse, a dog, an old chicken and 7.35 acres of rocks rocks and more rocks.

  4. #14
    Veteran Member
    Join Date
    Sep 2007
    Posts
    1,981
    Location
    Doniphan, Mo.
    Tractor
    Kubota L4240, B7800 & BX2660

    Default Re: 3 ph drifts down

    While you have it apart make sure you check the 2 o rings under the control valve.

  5. #15
    Platinum Member sd455dan's Avatar
    Join Date
    Oct 2012
    Posts
    968
    Location
    North Idaho
    Tractor
    Ford 3000-Rhino 554,Co-Op ,Honda ,Gilson riding mowers

    Default Re: 3 ph drifts down

    Quote Originally Posted by 600rider View Post
    Ok I have lived with this for a couple years so now is the time to fix it! I have a 2004 kubota B7510 HST and the the 3ph drifts down all the time! It doesn't matter if I am driving the tractor or if it is sitting running while I am doing something else. doesn't matter if it is at idle or full throttle. I have even been going down the road and tried to lock it in the up position with the knob in front of the seat. I am thinking it might be a seal on the lift cylinder. Any thoughts?? Thanks, Ken.
    I had another thought after posting the information on the rockshaft seal.
    If it is designed to where a small cover can be removed, like the pictured unit- that has a direct feed to the rockshaft cylinder it may be possible to test the cylinders leak down directly- without tear down...

    By accessing the direct port and then doing a leakdown test...if the cylinder is not leaking it could be o rings- but the test might nail it down without a full tear down hope this is helpful

  6. #16
    Super Member
    Join Date
    Feb 2008
    Posts
    9,392
    Location
    somewhere usa
    Tractor
    Deere 110tlb, 4520, x749, L130

    Default Re: 3 ph drifts down

    Quote Originally Posted by sd455dan View Post
    if it is like most tractors, the rockshaft seal if bad- results in your description, but the hydraulic control linkage would cause it to lift back up to the original position if the tractor had position control and the tractor was running..

    When not running the quick lowering is the most common result with a failed rockshaft seal...one more thing a rockshaft seal failure will not affect fluid level, it will just end up in the sump..Attachment 313934 Attachment 313935as can be seen in this picture the cylinder that the rockshaft piston slides in is open to the sump, this ones seal had completely disintegrated.
    Replacing the seal and honing the cylinder restored the 3 point lift, to as new operation.
    You can also check your work by using an air compressor and an inexpensive leak down tester as I did, this assures you that the seal is sealing correctly and that it didn't get damaged during installation Attachment 313940 besides those rockshaft covers aren't exactly light, and it's no fun taking it apart twice...

    I agree with this post^^^^ most likely the rockshaft seals are shot. The next possibility is the rockshaft valve is leaking and would need new orings too.

    While it is a good idea to make sure you have clean fluid I don't see where this would be related to the problem at hand.

  7. #17
    Elite Member
    Join Date
    Jan 2011
    Posts
    2,509
    Location
    Fanning Springs, Gilchirst County, North-Central Florida
    Tractor
    Kubota Tractor Loader L3560 HST 37-hp / 5,400 pounds

    Default Re: 3 ph drifts down

    To this point, the OP has NOT told us he has checked the fluid levels.

    Hydrualic fluid may be at 40% of "full" level, causing the problem.

    This would not be the first time someone has 600 hours on a tractor and has never checked the hydraulic fluid level, much less changed the hydraulic fluid and filter, and wondered why the equipment is not operating normally.
    Last edited by jeff9366; 04-21-2013 at 02:08 AM.

  8. #18
    Super Member
    Join Date
    Feb 2008
    Posts
    9,392
    Location
    somewhere usa
    Tractor
    Deere 110tlb, 4520, x749, L130

    Default Re: 3 ph drifts down

    Quote Originally Posted by jeff9366 View Post
    To this point, the OP has NOT told us he has checked the fluid levels.

    Hydrualic fluid may be at 40% of "full" level, causing the problem.

    This would not be the first time someone has 600 hours on a tractor and has never checked the hydraulic fluid level, much less changed the hydraulic fluid and filter, and wondered why the equipment is not operating normally.

    No.
    If there was not enough fluid the hitch might not raise fully or properly. The leaking down is a separate issue. I do agree that everyone needs to perform proper maintenance if they want good long term reliability and performance.

  9. #19
    Gold Member 600rider's Avatar
    Join Date
    Jul 2007
    Posts
    354
    Location
    union city pa
    Tractor
    2004 kubota b7510

    Default Re: 3 ph drifts down

    Yes I do check the tractor over on a regular basis. I check all fluids and belts tires and such. I think that if there wasn't enough fluid it would not raise at all or intermittently. I think my problem is the o-ring on the lift cylinder and have ordered the parts. I also will be changing the hydraulic filters and cleaning the screen. I will check the fluid but doubt I will change it as super udt is priced like gold! Thanks all for the help, Ken.

  10. #20
    Platinum Member sd455dan's Avatar
    Join Date
    Oct 2012
    Posts
    968
    Location
    North Idaho
    Tractor
    Ford 3000-Rhino 554,Co-Op ,Honda ,Gilson riding mowers

    Default Re: 3 ph drifts down

    One other thing 600rider , and you may already Know this, but I did not think it would hurt to include it.

    The main piston seal is a v type seal it will always be installed with the outer sealing lip facing the pressure side of the oil circuit.

    That way as the hydraulic pressure increases the lip of the seal will be pressed outward and in contact with the cylinder proportionally to the pressure of the fluid, so the higher the fluid pressure, the the tighter the lip presses outward.

    The tractor I replaced the seal on only employed one seal, and as you stated- your application requires a second seal... not sure if the back up seal is of the same type so can't advise on that ... Looks like your well on your way to getting the 3 point back to fully functional

Page 2 of 3 FirstFirst 123 LastLast

Similar Threads

  1. 2305 & 47inch vs. 7 ft drifts.
    By thetaxman in forum John Deere Owning/Operating
    Replies: 1
    Last Post: 02-07-2010, 11:22 AM
  2. 3-Point Hitch 3 pt hitch drifts down after hot
    By jrgman in forum Mitsubishi/Satoh
    Replies: 2
    Last Post: 09-01-2009, 06:41 PM
  3. Loader Drifts UP... Ideas???
    By jimdre in forum Parts/Repairs
    Replies: 5
    Last Post: 06-15-2009, 04:40 PM
  4. 3ph drifts down on 4110
    By mboulais in forum Mahindra Owning/Operating
    Replies: 6
    Last Post: 11-19-2004, 07:48 AM
  5. steering drifts to the left
    By varmint in forum Kubota Owning/Operating
    Replies: 0
    Last Post: 04-28-2003, 10:17 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
© 2014 TractorByNet.com. TractorByNet is a registered trademark of IMC Digital Universe, Inc. Other trademarks on this page are the property of their respective owners.