Page 1 of 2 12 LastLast
Results 1 to 10 of 12
  1. #1
    Platinum Member
    Join Date
    Nov 2005
    Posts
    647
    Location
    TX
    Tractor
    NH TC 40 A, AC 5020

    Default Can a hydrualic pump get weak?

    Wasn't a good day today. First I notice a 4" slit in the sidewall of my rear tractor tire. I mowed for about 3 hours with it like that. Figured a blowout was the worst that could happen.

    After mowing I put on a disc to turn a small area of ground and the 3pt would barely lift up the disc, not even completely off the ground. By then it was late, so I didn't get to check the fluids or filter, but they were OK not to long ago and I saw no leaks. I keep it in a garage and have cardboard under it so I would have noticed, and there was no visable oil on the tractor either. It lifted the disc last September, but I haven't used it since. I didn't notice problems with the mower on because there is no need to raise it all the way. Other than checking the fluid and filter, can the pump get weak? Anything else I can check to see what's wrong? The tractor is 140 miles away, so I cany get it untill next weekend.

    By the way, it's not the tire, it was at full height all through the mowing. Thanks for any help. MP

  2. #2
    Super Member Farmwithjunk's Avatar
    Join Date
    Aug 2005
    Posts
    7,514
    Location
    Mt Washington, Kentucky
    Tractor
    Where do I begin.....

    Default Re: Can a hydrualic pump get weak?

    A little background info would help a great deal. What sort of tractor? How old? (hours) How heavy was the mower? How heavy is the disc?

    Using the mower for a prolonged period could have heated up the hydraulic oil. That makes a weak pump seam even weaker. (YES, a hydraulic pump can and will "get weak")

    Independent PTO's will make matters worse sometimes. (They use hydraulic clutch)

    Certain brands will tend to loose some lifting ability over the course of a work day. That's even more common when using the DRAFT mode as opposed to position control, if that applies to your tractor.


  3. #3
    Gold Member
    Join Date
    Apr 2000
    Posts
    369
    Location
    northern calif.
    Tractor
    JD-970

    Default Re: Can a hydrualic pump get weak?

    Kossetex, the easy way to do a quick check on the hydraulic pump is to run a ram (loader rams will do) all the way out or in and listen (or feel) for the pump pressure relief valve vibrating of it's seat. Any good hyd pump will do this easy.
    This test does not check out the gpm rate of the pump, but generally if pump is strong enough to blow relief valve it's gpm is probably ok. Also, internal leaks to suction or sump in spool valves or three point lift hyd system may prevent pump from getting pressure up to the blow off point as well.

    lot's of luck,

  4. #4
    Platinum Member
    Join Date
    Nov 2005
    Posts
    647
    Location
    TX
    Tractor
    NH TC 40 A, AC 5020

    Default Re: Can a hydrualic pump get weak?

    FWJ, It is a 20+ year old AC 5020. It is a small 2 cyl diesel that has 1350 hours on the meter, but that is wrong. It probably has more but the meter seems to move slow even at pto speed. Can a hydraulic pump be changed IF I can find one and how big a deal is it?

  5. #5
    Veteran Member
    Join Date
    Jul 2003
    Posts
    1,993
    Location
    MN
    Tractor
    Ford 960, 7700, TW20, 1720; IHC H, 300; Ollie S77

    Default Re: Can a hydrualic pump get weak?

    Typically a hyd pump gets weaker in a slow way. You will notice it getting weaker over _years_, not over a week.

    There are several valves & bypasses & such. One of them is likely the trouble. The pressure relief valve could have a speck of dirt in it, holding it open & not letting the hyd work.

    Your filter can easily be plugged, that is where I would start, new filter.

    The oil can get water in it, esp if the tractor sits outside or you get a lot of humitity & frost type of weather. Oil & water makes foam, which makes for a weak pump. You can look for foamy oil if it's hot, or open the hyd oil drain just a smidgen if it's cold & check for a bit of water on the bottom.

    Your oil can be low, & that gets air in the system, which foams the oil.

    About the last thing I'd worry about, with your symptoms, is a weak pump. This seemed to happen too fast to be a weak pump.......

    --->Paul

  6. #6
    Elite Member
    Join Date
    Mar 2002
    Posts
    3,505

    Default Re: Can a hydrualic pump get weak?

    Your tractor may have a clogged internal hydraulic pick-up screen. Follow the return line from the pump to where it exits the tractor and see if there is a removable plate. If so, you will need to drain the fluid to access it.

  7. #7
    Platinum Member
    Join Date
    Nov 2005
    Posts
    647
    Location
    TX
    Tractor
    NH TC 40 A, AC 5020

    Default Re: Can a hydrualic pump get weak?

    George, Paul, All, Thanks for the replies so far. My 1st though was to change the fluid and check the screen. I last cleaned the strainer at 1000 hrs, but it was completely clean. I had noticed during a fluid check that the hyd fluid seemed foamy, but the level was right. I'll change it and see. The 3pt hitch has always leaked by when the tractor was off but it worked fine while it was running, so I paid it no mind. I'll let you all know when I change it this weekend or next. Thanks for all the advice. It is appreciated! MP

  8. #8
    Epic Contributor
    R.I.P.
    jinman's Avatar
    Join Date
    Feb 2001
    Posts
    21,014
    Location
    Texas - Wise County - Sunset
    Tractor
    NHTC45D, NH LB75B, Ford Jubilee

    Default Re: Can a hydrualic pump get weak?

    This is probably not the problem, but I had a momentary problem with my 3PH when one of my remote valve handles was sticking and not returning completely to the open center position. If you have a remote or FEL valve that diverts fluid before the 3PH, that could be the problem. Also, is your pump very hot? If it is getting extremely hot or the engine seems to be loaded, your hydraulics could be working against a restriction and keeping the relief vavle open as others have indicated. Since you said the oil is foamy, it could also be sucking air or cavitating. Any of those things are really hard on a pump and drastically shorten its life.

  9. #9
    Elite Member RobJ's Avatar
    Join Date
    Jul 2005
    Posts
    3,471
    Location
    Spring, TX (Houston)
    Tractor
    Kubota L2500

    Default Re: Can a hydrualic pump get weak?

    I've never replaced a pump that was weak. Pumps generally have more power than needed so there is plenty of reserve. If it gets a lot of dirt through it it would more than likely wear out the seals and bushings and just start leaking. This was the case on my brother in laws jd350, it worked fine just blew oil out of the shaft seal, the bushing was so worn the seal couldn't control the amount of oil bypassing the bushing. I called a friend that owns a hydraulic business and he confirmed this. Just make sure the pump isn't getting air in it and check for blockages and such.

    Good Luck,
    Rob

  10. #10
    Epic Contributor Soundguy's Avatar
    Join Date
    Mar 2002
    Posts
    48,593
    Location
    Central florida
    Tractor
    ym1700, NH7610S, Ford 8N, 2N, NAA, 660, 850 x2, 541, 950, 941D, 951, 2000, 3000, 4000, 4600, 5000, 740, IH 'C' 'H', CUB, John Deere 'B', allis 'G', case VAC

    Default Re: Can a hydrualic pump get weak?

    I agree with the others... might be real thin hyd fluid.. like aw32 or even thinner utf base. Might have some wear in the system too. Don't have any spools kicked open causing reliefs to lift and pump to overwork, thus heating and thinning the oil further?

    In the old days.. if that tire was a tube type.. the farmer would dismount it, and then lace it up with #10 wire, and lay a boot on the inside, and go... I've seen lots of tractors with tread bolted or laced on!!

    Soundguy

    Soundguy

Page 1 of 2 12 LastLast

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.