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Bobcat T-250 Low Charge Pressure Issue

Discussion in 'Compact Track/Multi Terrain Loaders' started by nightrider05, Oct 18, 2014.

  1. nightrider05

    nightrider05 Member

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    Hello,

    First off I want to introduce myself as this is my first post, and say thanks for the info I have gathered so far. I have browsed the forum and finally decided to join and see if you guys could help me some more. I am a first time equipment owner, and recently purchased a 2003 Bobcat T-250.

    Background:
    Purchased T250 with 1570 hours. Machine was on its second owner and has been mainly used on a farm. The day I went to look at it, it started acting up...or thats the story I received anyways. Previous owner swore he had used it the day before with zero issues. He lowered price and I took a gamble since they seemed like honest people....which is what has lead me here. When purchasing, I also discovered the deluxe display was damaged and you could not read anything on it..so I didn't know it had low hydraulic pressure. The bucket would lift up, but wouldn't want to go back down.....and the bucket would tilt back, but not want to tilt back forward.

    When purchased, the machine would fire up and run for around a minute before you get the low charge pressure codes(05-14 and 05-15). The charge pressure(according to the deluxe display that I replaced) starts out around 350-400 and slowly drops down to the shut off pressure of 150(sometimes read as low as 50 while shutting down). I had read online that a common issue is the hydraulic pressure sender, so I replaced it. The new sender still gives me the same pressure. Correct pressure according to the manual is 410-470

    At this same time I also replaced the hydraulic filter(was relatively clean..no metal chunks or flakes but there are some sparkles in the fluid), and the Case Drain Filter. The case drain filter appeared to have never been removed before and was the original one. It had metal flakes in it,and a decent amount of them. The flakes were silver and I verified that there was no brass looking shavings. A key thing to mention here is that the metal case drain filter appeared to have sucked in a bit, and the end of it had come apart. There was a chunk about the size of a pencil eraser missing.

    Next, I moved on to the pressure relief valve. When I pulled it out I found pieces of the case drain filter stuck between the Poppet and the seat. The poppet was also stuck in place on the shaft and would not move freely. I cleaned it up, inspected the spring, and lightly sanded the shaft so the poppet would move smoothly. There were 7 shims under the spring and I made sure to install all of them. I filled the hydraulic fluid back up to replace the fluid I lost.

    When I fired it back up, the pressure seemed to be holding a bit better initially but would still drop down to 150(no longer down to 50). I fired it back up to see if maybe there was just air in the lines, and when I attempted to move the bobcat(after releasing the brake), the pressure dropped down to around 18PSI and now will not go any higher.

    So now I am stuck. While I am hoping its not my pump, it is starting to look like a likely culprit. Are there any other valves that could simply be stuck open? Any inline screens or filters that could be clogged?

    Any help is greatly appreciated.

    -Jason
     
  2. crewchief888

    crewchief888 Senior Member

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    if you found metal and brass in the filters, you likely have 2 problems.
    charge pump and drive motors.

    you can furtehr test by capping off the drive motors at the pumps, and recheck the charge pressure. if it stays up, the problem is in the drive motors.

    your lift/tilt problem is a seperate issue. most likely debris in one of the aux solenoids, and it's stuck open.

    :drinkup
     
  3. nightrider05

    nightrider05 Member

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    I kept all of the metal, and it is all silver...not brass. I was told to look for any brass chunks.

    The only brass looking debris has been the pieces of the case drain filter.

    Thank you for your input. I will have to see where I can find some caps locally. How would I go about finding out what size caps they are?
     
  4. nightrider05

    nightrider05 Member

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    Also, I'm assuming the motor has to come out to remove the main pump?

    I have been working on getting Bobcat out here..but its going to cost a pretty penny just to have them look at it. At this point I may just bite the bullet and let them diagnose what all is actually wrong.
     
  5. willie59

    willie59 Administrator

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    Not just yet, you already have Bobcat here in a way, crewchief works for a Bobcat dealer. You need to do what he said and cap off the drive motor lines at the pump and check your pressure. I'm guessing #12 JIC plugs/caps, crewchief could confirm that.
     
  6. nightrider05

    nightrider05 Member

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    Will do. I will try to find some plugs/caps this week if he is able to confirm it. I have already noticed I need some anyways..have had to replace a decent amount of fluid just trying random things.
     
  7. crewchief888

    crewchief888 Senior Member

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    i'm pretty sure they are -12.

    if you found chunks of a damaged case drain filter, you may have some serious problems.
    or the drive motors may have been replace and nobody bothered with the case drain.....

    lets see what happens to your charge pressure with the motors capped off, before i speculate on anything else...


    :drinkup
     
  8. nightrider05

    nightrider05 Member

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    [​IMG]

    That was the case drain filter. I found about half of the missing piece.

    The sludge around the base is the junk that was in it. I spread it out after the picture and it was all fine silver metal shavings.

    I'm pretty sure no major work has been done to this machine. This is a weekend project, so I will locate some caps/plugs this week and play around next weekend
     
    Last edited: Oct 19, 2014
  9. nightrider05

    nightrider05 Member

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    If I was wanting to a good assortment of caps/plugs for working on this machine...what would you guys say would be good sizes to get?
     
  10. crewchief888

    crewchief888 Senior Member

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    -6 -8 -12 will cover most of what you need.

    hyd supply stores usually have an assortment already packaged in a nice plastic flip top box.

    :drinkup
     
  11. nightrider05

    nightrider05 Member

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    Thank you.

    If it is worth noting, the day I got it home I was able to drive it around for about 10 minutes at higher RPM before it would shut down. To me it almost seem like something, somewhere is blocked and restricting flow. However I know I am still being optimistic.
     
    Last edited: Oct 19, 2014
  12. nightrider05

    nightrider05 Member

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    Last night I decided to swap the pressure sender back out. I noticed that no fluid came out of the open fitting this time. The first time I swapped it out, fluid came out at a steady rate.

    The sender is located just outside of the control block on mine.

    What I'm wondering now is if maybe there is a blockage in that line giving me inaccurate readings. I already know there has to be a blockage in that control block since my tilt and lift functions weren't working right.

    Old sender still showed low pressure by the way.
     
  13. crewchief888

    crewchief888 Senior Member

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    you're just fooling yourself think a "clogged" line is giving you inaccurate readings.

    since you already found debris in the filters, and a damaged case drain, you have a (at the very least) a failed charge pump.
    the charge pump and hyd pump are sold as an assembly, typically if the charge pump takes a dump, the hyd pump is damaged as well.


    :drinkup
     
  14. nightrider05

    nightrider05 Member

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    While I try to stay optimistic, I have already located a cherry picker to pull the motor, and a couple places to rebuild the pump near st.louis.

    I just like to rule out other possibilities first. At this point I will just be happy if the damage is isolated to the main pump and not the drive motors.
     
  15. nightrider05

    nightrider05 Member

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    It's a bummer that I got hosed on this thing. If it's just the pump, I will still be "ok"...anything more than that and I'm hosed.

    At least I get to learn how to work on skidsteers...have worked on every thing else I own. May as well learn this thing too.
     
  16. nightrider05

    nightrider05 Member

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    Removed about a half ounce of fine metal from oil tank today with a magnet. Some flakes of brass were in it.

    Have a cherry picker and a rebuilder for then main pump. Keeping my fingers crossed that I can get by with just replacing main pump.

    Ordered a plug/cap kit online so I can block off the drive motor lines and test pressure before I do all the work.
     
  17. nightrider05

    nightrider05 Member

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    Any good tips on removing tracks from a non running machine?

    Tensioners are already loose and grease is out. Book says to just use pry bars, but I'm questioning if they ever actually did it with just pry bars. Machine is in a bad spot where I can't get any sort of comealong hooked to the front of the track to pull slack forward.
     
  18. nightrider05

    nightrider05 Member

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    Also, I can't run the tracks forward to put pipes in to allow the track to slide over idler, as I have seen in some how-to's. Charge pressure won't go above 30 psi at this point. Nowhere near enough to release brake.

    Can I remove rear sprocket to get a little more slack?
     
  19. crewchief888

    crewchief888 Senior Member

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    make sure the tensioner is all the way back. it will hit the end of one of the bolts holding the (front) inspection cover on.

    another hint is to raise the machine only high enough for the tracks to clear the bottom rollers., otherwise you are fighting the weight of the track.

    the sprockets can be removed, but thats usually a chore in itself if they are rusted.
    there should be some tapped holes in the face of the sprocket to run some long bolts into to use as jack screws.


    :drinkup
     
  20. willie59

    willie59 Administrator

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    I'm just curious, why are we removing tracks from a non-operating T250 that's in a bad spot? There has to be a good reason for this. :yup