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  1. #1
    Gold Member
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    Mar 2004
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    250
    Location
    South East Pa.
    Tractor
    PT425

    Default Fictitious Scenario

    You are mowing on a 20 or so degree slope with your trusty PT. Suddenly the engine stops. The PT starts to roll down the hill. You try to engage the pin brake. Just clicks. Machine rolls down hill and stops. Since this is like towing your machine with the tow valve closed what kind of damage does a PT incur.

    sg

  2. #2
    J_J
    J_J is offline
    Super Star Member J_J's Avatar
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    Sep 2003
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    15,783
    Location
    JACKSONVILLE, FL
    Tractor
    Power-Trac 1445, KUBOTA B-9200HST

    Default Re: Fictitious Scenario

    I have noticed that with the engine off. if a wheel is lifted off the ground, I can turn the wheel by hand, but very slowly.

    I suspect that the wheel motors will try and turn but will not get very fast.

    In your fictitious situation, I believe the PT will slowly move downhill, You might even be able to turn the steering wheel somewhat.

    When the hose burst on my wheel motor, the PT went backard rather quick, The believe that the wheel motors were acting like a pump and forcing all the fluid out the burst hose.

  3. #3
    Epic Contributor MossRoad's Avatar
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    Aug 2001
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    22,513
    Location
    South Bend, Indiana (near)
    Tractor
    Power Trac PT425 2001 Model Year

    Default Re: Fictitious Scenario

    I don't believe my PT would roll down that hill if the engine were to stall. The reason I think this is because I have run the unit out of gas a few times. The engine stopped, and so did the PT. It didn't coast, roll or move. The engine died and the unit stopped instantly. So, if it were to roll, I would suspect it would be slow enough that the pin brake would engage. The next time I am out at our property that has a large hill on it, I will try to see if it rolls with the engine off. Probably won't be until the fall, though.

    If it did start rolling, I would wrestle the steering to turn across the hill, and it would stop. I would not fear a tip over on a 20 degree side hill with my PT at low speed.

    As for damage to the pump, I suppose if the unit had enough weight and/or momentum to start or keep it rolling after the engine died, damage could occur to the pump. I know PT says not to tow the unit without releasing the tow port or damage will occur. But I think they are talking about more distance than a foot or two. I think they are talking about hooking it up to your pickup truck and towing it out of a field or out of a mud hole. If the tires gain traction their motion could force fluid back into the tank and cause suction on the pump side. Since the pump isn't turning, it might try to force the engine to turn over, suck fluid past the seals, etc.... Someone else with better knowledge of hydraulics should chime in here.

    Now if a hose burst, the unit might run away, but the pump would not be damaged because the pressure would be relieved by the hole in the hose. Again, my guess, not fact.

  4. #4
    Gold Member
    Join Date
    Feb 2004
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    271
    Location
    Kingston, WA
    Tractor
    JD L130

    Default Re: Fictitious Scenario

    I was going to post this type of scenario as an afterthought to the brakes thread: Link

    Without brakes there is really no way to stop a PT rolling down a hill in the event of an engine failure (be that an actual failure or running out of gas).

    Depending upon the slope, I think the PT without brakes will continue to roll down the hill. If the hydrostatic motors are like a hydrostatic transmission, then under normal circumstances they will not turn unless hydraulic fluid is pumped through them. However this doesn't apply where inertia can overcome the resistance in the motors or transmission. I'm sure someone will correct me if I'm wrong about comparing the motor and transmission. [img]/forums/images/graemlins/crazy.gif[/img]

    The suggestion for such a situation is to drop your bucket (if attached) or to hit the big red STOP button that will eject a grappling hook out the back (PT Optional Part#T3999-12). [img]/forums/images/graemlins/wink.gif[/img]

  5. #5
    Epic Contributor MossRoad's Avatar
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    Aug 2001
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    22,513
    Location
    South Bend, Indiana (near)
    Tractor
    Power Trac PT425 2001 Model Year

    Default Re: Fictitious Scenario

    I didn't get that option! [img]/forums/images/graemlins/tongue.gif[/img]

    As for dropping the bucket, that works great if you have it on. If you have the mower, it has wheels and would roll, assuming the PT will roll if the engine dies.

    I really wish I had it at our property with hills to test. I would take pictures and everything(assuming it stayed in one place and did not roll, of course).

  6. #6
    Epic Contributor MossRoad's Avatar
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    Aug 2001
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    22,513
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    South Bend, Indiana (near)
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    Power Trac PT425 2001 Model Year

    Default Re: Fictitious Scenario

    DOH!!! I could test it on the ramps to my trailer. Next time I get it out, I will do that and report back.

  7. #7
    Gold Member
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    Feb 2004
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    271
    Location
    Kingston, WA
    Tractor
    JD L130

    Default Re: Fictitious Scenario

    Okay this is what happened to me while going down a very steep hill today with my lawn tractor and its hydrostatic transmission. This tractor has a forward/reverse treadle sort of like the PT except that its mounted on one side of the tractor and you use your right foot to control it. With your foot off, the tractor will stop on level ground, on hills it will continue to roll slowly or quickly depending upon physics. For fun, I decided to go down a hill with a wagon full or rocks and heavy dirt (actually, I think it was really old manure cuz that's what a lot of it smelled like) and I tried slowing/stopping the tractor by going gently pressing on the reverse part of the treadle. Instead of slowing or stopping the tractor sped up instead. [img]/forums/images/graemlins/shocked.gif[/img]

    So I decided to try this again the next time down. What I learned was that the tractor sped up because the rear wheels came to a stop and then the tractor slid (or skidded) down the grassy hill instead. I imagine the same thing would have happened if I had tried to jam on the brake. But I would wonder if the same thing would happen to a PT. Would all four wheels lock up like that or would some lock up and others would still have grip? I will have to try this with 80lbs of weight on the back to see if I get better traction that way.

    I know its not the same as a PT but I don't have a PT and I think some of the concepts are bound to carry over.


  8. #8
    Veteran Member FOURTEEN's Avatar
    Join Date
    Jan 2004
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    1,028
    Location
    Efland - Triangle of North Carolina.
    Tractor
    2004 Power Trac PT-425

    Default Re: Fictitious Scenario


    Some folks worry way too much about scenarios that have only a tiny, tiny chance of ever happening!!!

    What if a dog runs away with your shoes??


    What if 100' of barbed wire hits you in the mouth??

    What if Kerry is elected??

    What if lightening splits your PT in two??

    What if some jerk makes fun of your 'what if's??

    What if your dog gets run over by an airplane??

    What if your PT wears out and you have to buy a nice new one rather than using the same old one forever??

    What if you run out of 'what if's??

    [img]/forums/images/graemlins/grin.gif[/img] [img]/forums/images/graemlins/grin.gif[/img] [img]/forums/images/graemlins/grin.gif[/img] [img]/forums/images/graemlins/grin.gif[/img]

  9. #9

    Join Date
    May 2004
    Posts
    247
    Location
    Washington - West Cascades
    Tractor
    PT-422

    Default Re: Fictitious Scenario

    MossRoad, careful with that ramp, you dont want to go off it to one side. [img]/forums/images/graemlins/ooo.gif[/img]

    My pt422 rolls real slow when i shut it down but i havent tried to turn it. I guess I thought it wouldn't turn. I'll have to try that out next time.

  10. #10
    Gold Member
    Join Date
    Mar 2004
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    250
    Location
    South East Pa.
    Tractor
    PT425

    Default Re: Fictitious Scenario

    Really not a what if game. When I was at Tazwell with Terry he said if you run out of fuel on a hill make sure you apply the parking break or the machine will roll. Didn't think to much about it then. We also talked about the tow valve must be open to move the machine or damage will result. I guess I could ask the question this way. How far would a PT have to be towed or rolled to produce damage and what kind of damage would result.

    sg

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