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  1. #1
    Veteran Member lhfarm's Avatar
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    NH TC40DA

    Default Where to place pressure gauge in simple open center system?

    Back to working on my 1949 jeep 3pt lift that uses a power-up, gravity-down ram (the ram does have a "return hose" that dumps into the tank). Not many places to install pressure gauge, but assuming I should but in a tee just in front of the valve inlet. Assume I should take the high pressure measurement while extending ram.

    I want to test both the pump operation as well as the valve operation. What should I observe at the pressure gauge that will tell me if the valve is operating correctly?

    Any advice or instructions appreciated.
    Barry
    Lawson Hill Farm
    NH TC40DA
    '64 IH Cub Lo-Boy
    '47 Willys Jeep CJ2a w/ PTO
    '49 Willys Jeep CJ3a w/ PTO & 3pt lift
    http://www.farmjeep.com/

  2. #2
    Bronze Member
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    Jun 2011
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    central,wi.
    Tractor
    TYM 350

    Default Re: Where to place pressure gauge in simple open center system?

    Place the gauge before the valve. Pressure readings will depend on the pumps rated capacity and the resistance to flow. With the control valve in neutral little to no pressure will show. Max pressure will read when cylinder is fully extended and relief in control valve is openning.

  3. #3
    Super Star Member J_J's Avatar
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    JACKSONVILLE, FL
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    Power-Trac 1445, KUBOTA B-9200HST

    Default Re: Where to place pressure gauge in simple open center system?

    Install the gage in a tee in the IN port of the valve.

    The gage will tell you the resistance to the pumps flow in PSI.

    If the cyl and the valve is good and not leaking, the gage will reflect the force that the cyl is developing.

    If you know the valves relief pressure, and can see it on the gage you can assume the pump is doing it's job.
    J.J.

    When I works, I works hard. When I sits and thinks, I goes to sleep.

    Git er done.

  4. #4
    Veteran Member lhfarm's Avatar
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    Default Re: Where to place pressure gauge in simple open center system?

    Quote Originally Posted by J_J View Post
    Install the gage in a tee in the IN port of the valve.

    The gage will tell you the resistance to the pumps flow in PSI.

    If the cyl and the valve is good and not leaking, the gage will reflect the force that the cyl is developing.

    If you know the valves relief pressure, and can see it on the gage you can assume the pump is doing it's job.
    So I'm getting little or no movement on the gauge, at any time. But the lift does go up and down. I can lift my weight, but not two of us ~400 LB. It took a lot of cycles before it would lift anything. I removed the filler plug on the reservoir and it was pressurized - blow out a small amount of fluid. I think I finally have all the leaks stopped but not sure what to do next.

    It did seem when it first started lifting me (after I had cycled it with no load several times), it worked well and the lift moved up quickly. Then it would only work some of the time, until I bleed it (see above). So I'm thinking the pump may be OK and the valve is just not working right all the time.

    For now, I'm going to take the gauge out of the circuit and take it to the barn and try lifting a small 2-12 plow. If it does that, I'll declare victory.

    Thanks for the help.
    Barry
    Lawson Hill Farm
    NH TC40DA
    '64 IH Cub Lo-Boy
    '47 Willys Jeep CJ2a w/ PTO
    '49 Willys Jeep CJ3a w/ PTO & 3pt lift
    http://www.farmjeep.com/

  5. #5
    Super Star Member J_J's Avatar
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    Power-Trac 1445, KUBOTA B-9200HST

    Default Re: Where to place pressure gauge in simple open center system?

    Are you sure you installed the gage in a tee in the IN port of the FEL valve?

    Did you extend or retract any cyl to the max so the relief comes on.

    If you have things connected correctly, you will show every psi the hyd system is developing.

    If you did not see any pressure, then things are not connected correctly.

    Rules are rules, and if the pump is good and the parts are good, then you will develop pressure.

    Leave the gage installed, as it is a valuable tool for trouble shooting, and useful for monitoring the hyd system.
    J.J.

    When I works, I works hard. When I sits and thinks, I goes to sleep.

    Git er done.

  6. #6
    Bronze Member
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    central,wi.
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    TYM 350

    Default Re: Where to place pressure gauge in simple open center system?

    Normally the reservoir should be vented.

  7. #7
    Veteran Member lhfarm's Avatar
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    NH TC40DA

    Default Re: Where to place pressure gauge in simple open center system?

    Quote Originally Posted by J_J View Post
    Are you sure you installed the gage in a tee in the IN port of the FEL valve?

    Did you extend or retract any cyl to the max so the relief comes on.

    If you have things connected correctly, you will show every psi the hyd system is developing.

    If you did not see any pressure, then things are not connected correctly.

    Rules are rules, and if the pump is good and the parts are good, then you will develop pressure.

    Leave the gage installed, as it is a valuable tool for trouble shooting, and useful for monitoring the hyd system.
    This is a very simple system and the value is under the jeep bed. So the Tee is between the high side of the pump and about a foot short of the inlet side of the control valve where it fits/can be seen. So I can't leave it in place. The gauge may not be working. I purchased it from Northtool and it was inexpensive.

    I cycled the lift several times with no load and even when it was completely extended, I didn't hear any change in engine speed. So I'm not sure the valve is working correctly. It is a very simple affair but I don't know of a modern replacement. Since this is an antique, meant for show, I'd be happy if I can just lift the plow. After the show season, I might drop the lift and see if I can get the valve working.

    Quote Originally Posted by triptester View Post
    Normally the reservoir should be vented.
    The lift is installed according to these instructions from 1947 - Farm Jeep -Newgren Installation Instructions

    There is no vent, but wonder if I can make vent by extending the fill tube (see here http://farmjeep.com/img/newgren_inst...diagram4.jpg)?

    Thanks for all the help.
    Barry
    Lawson Hill Farm
    NH TC40DA
    '64 IH Cub Lo-Boy
    '47 Willys Jeep CJ2a w/ PTO
    '49 Willys Jeep CJ3a w/ PTO & 3pt lift
    http://www.farmjeep.com/

  8. #8
    Gold Member
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    Canton, TX
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    JD 301A and yanmar YM2500

    Default

    If you can take the line from the pump to the valve loose and run it to the tank if possible and start the jeep. See if you even have flow from the pump.

  9. #9
    Veteran Member lhfarm's Avatar
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    Central Indiana
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    NH TC40DA

    Default Re: Where to place pressure gauge in simple open center system?

    Quote Originally Posted by medic0648 View Post
    If you can take the line from the pump to the valve loose and run it to the tank if possible and start the jeep. See if you even have flow from the pump.
    I tested the pump for flow before I hooked it up to the lift tank. There is flow. Also, the lift does move up and down, but doesn't have a lift power. It will lift 200 lb, but not twice that.

    Thanks,
    Barry
    Lawson Hill Farm
    NH TC40DA
    '64 IH Cub Lo-Boy
    '47 Willys Jeep CJ2a w/ PTO
    '49 Willys Jeep CJ3a w/ PTO & 3pt lift
    http://www.farmjeep.com/

  10. #10
    Gold Member
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    Canton, TX
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    JD 301A and yanmar YM2500

    Default

    Will it hold the load in the air? If it won't it may either be the seal in the cylinder or the valve leaking internally.

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