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  1. #1
    Veteran Member
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    Power Trac PT1445

    Default Locked up and nowhere to go

    I'm looking for ideas...

    A couple of times last winter, and then again yesterday, I have had the following problem.

    I go to start the tractor, and it starts normally, although the idle sounds a little labored. You go to release the brake, and then raise the arms, only to discover that none of the auxiliary hydraulic circuits work.
    No lift/curl
    No Q/A
    No steering

    The draft control puts some hydraulic fluid into the arms. If you really muscle it, the steering 'works' but it is almost as if you are manually pumping oil in to the steering circuit. The first few times it happened, it was really cold- for California, in the thirties and I put it down to low temperature. Yesterday, it was 60F, and I had used the PT earlier in the day for brush cutting, on a steep slopes.

    Stopping and restarting the tractor after cycling all of the circuits has the same effect. This time, I noticed that while cycling the parking brake, I heard a clunk from in front of me, I think in the 3-way valve bank (Q/A, curl, FEL).

    I called Terry last time, and he suggested removing the check (pilot?) valve in the front loader arm control and removing any debris that I found. I removed it and found no debris, and the problem went away.

    Sooooo.... My question is what is going on and what should I do to fix it?

    Clean the pilot valve again?
    Add a small inline filter?
    Look at something else again?
    Filter the entire hydraulic tank?

    I did a search on locked/frozen hydraulics and I couldn't come up with anything. Anyone else have this issue?

    Given the steep slopes and WOT operation to run the brush cutter, I could easily see that some dirt/debris in the hydraulic tank could have gotten knocked loose.

    Thanks in advance...

    All the best,

    Peter

  2. #2
    Elite Member woodlandfarms's Avatar
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    Default Re: Locked up and nowhere to go

    So, my tractor had something similar going on and I am not sure what is/was the problem. I say is because I have not had the chance to really test it since re-installing.

    On my PT, the PTO out and the Steering / Lift out from the pumps run into a common block. That block has a two bypass (pressure relief) valves in it,as well as the PTO actuator. The Bypass valves will release pressure if the PTO is activated and not connected, and will do the same for the steering. Staying with my Steering Lift circuit, the fluid either diverts back to the tank via the bypass valve, or moves forward to the high pressure filter. From that filter it moves to the Accumulator, which distributes to the lift, draft and steering. For me all of this takes place down the left side of the tractor (drivers side if you are in a car).

    Terry said mine was clogged up, had me remove a couple of parts, basically an elbow on the exterior, then underneath a hex key plug with a small hole drilled in it. Removing and cleaning (with no debris evident) did not clear up, so I sent mine in for repair.

    I re-installed. It worked perfectly once, then did the same thing again, but I had to get on a plane so I have not had the chance since to find out if this is the problem, or if I also have a problem back at my relief valves at the PTO actuator block.

    If I had better knowledge of hydraulics, I would seriously consider installing some high pressure filters but I am so clueless I am afraid I would kill the tractor with my modification.
    Power-Trac 1850, grapple, hoe, 90" mower, 72" box blade

  3. #3
    Elite Member woodlandfarms's Avatar
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    Default Re: Locked up and nowhere to go

    Peter, in re-reading your post this is exactly what my symptoms where. If you have a bypass valve in your steering circuit pull it and make sure it is clean.

    Yes, the draft control will activate the arms, but that is because there is some back feeding going on if I remember correctly.

    Also, I traced the problem with the heat method. I started the tractor cold, and let it do its thing for a couple of minutes, then I started feeling the hoses. Hot ones had fluid, cold ones did not. That is how I traced my problems down.

    Poor mans method but it worked...

    Also, my system while sick activated randomly with that clunk. I felt if I played with enough things on the tractor (those problem circuits) it would activate, but it turned out it was just time and pressure building up. You just had to wait for the system to pressurize enough to get the thingy to activate.
    Power-Trac 1850, grapple, hoe, 90" mower, 72" box blade

  4. #4
    Platinum Member
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    PT 1845, Bobcat A300, JD Trail Gator

    Default Re: Locked up and nowhere to go

    I have not experienced this problem and I have an 1845. That said, if I were experiencing the problem on my 1845 I would look first at the "RPS" valve block. The diagrams I have for the 1845 show the auxiliary circuit flow to be through the RPS valve block and then to the valve block for the lift/tilt/auxiliary PTO. The symptoms sound like a malfunctioning valve possibly caused by dirt in a valve.

  5. #5
    Veteran Member
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    Default Re: Locked up and nowhere to go

    Thanks for the suggestions. I don't have hydraulic schematics, which puts me at a bit of a loss sometimes.

    Does your 1845 have a prefilter prior to the RPS the way woodlandfarms does?

    All the best,

    Peter

    Quote Originally Posted by Bob999 View Post
    I have not experienced this problem and I have an 1845. That said, if I were experiencing the problem on my 1845 I would look first at the "RPS" valve block. The diagrams I have for the 1845 show the auxiliary circuit flow to be through the RPS valve block and then to the valve block for the lift/tilt/auxiliary PTO. The symptoms sound like a malfunctioning valve possibly caused by dirt in a valve.

  6. #6
    Platinum Member
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    Default Re: Locked up and nowhere to go

    Quote Originally Posted by ponytug View Post
    Does your 1845 have a prefilter prior to the RPS the way woodlandfarms does?

    No. I have attached some diagrams--they may or may not be anything like your 1845.

    P.s. My impression of the filter on Woodlandfarms machine was that it was before the hydraulic accumulator.
    Attached Files Attached Files

  7. #7
    Elite Member woodlandfarms's Avatar
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    Default Re: Locked up and nowhere to go

    Yup, the filter is after the PTO actuator block (Bypass valve) and the accumulator.
    Power-Trac 1850, grapple, hoe, 90" mower, 72" box blade

  8. #8
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    Default Re: Locked up and nowhere to go

    Update: Terry suggested that I clean out the pinhole in the steel block downstream of the RPS valve.

    The block (anyone know the name?) has four ports stamped P, S, A, and G. On my 1445, the "G" (for gauge) supplies hydraulic to the draft control. When you take off the hose, and the "Tee" fitting, inside is a small allen head set screw. In the center of the allen head set screw is a pinhole. Terry thought that it was 0.0018" or so. All I know is it looks minuscule.

    On my machine, the "A" port has the accumulator on it.

    I was imagining that Woodlandfarms filter went between the RPS block and this block. Is this where the brake tender connects up on the slope mowers?

    All the best,

    Peter

    Quote Originally Posted by woodlandfarms View Post
    Yup, the filter is after the PTO actuator block (Bypass valve) and the accumulator.

  9. #9
    Elite Member woodlandfarms's Avatar
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    Default Re: Locked up and nowhere to go

    The block does have a name, it is in my manual but my manual is up north. I think I posted it in my tirade about this. I did the same thing, removed the elbow, pulled out the cap with the pinhole. I think the block is Aluminum, at least mine is.

    I am really interested in what is going on with yours and what your resolution will be.

    http://www.tractorbynet.com/forums/p...tilt-dump.html

    Here is a picture of the block removed, as well as a picture of my High Pressure filter.. It is located on the gas tank next to the battery under the draft control.

    yes, this is where the tender hooks up. But it hooks up before this little pinhole valve, so the brakes will work but nothing else. Frustrating not having a diagram.
    Attached Thumbnails Attached Thumbnails -img_5094-jpg   -img_5095-jpg   -pict0905-jpg  
    Power-Trac 1850, grapple, hoe, 90" mower, 72" box blade

  10. #10
    Elite Member woodlandfarms's Avatar
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    Default Re: Locked up and nowhere to go

    A better pix of the filter
    Attached Thumbnails Attached Thumbnails -pict0953-jpg  
    Power-Trac 1850, grapple, hoe, 90" mower, 72" box blade

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