Front hoist for snowplow won't lower.

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by kmmontandon, Jun 6, 2025.

  1. kmmontandon

    kmmontandon Bobtail Member

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    May 21, 2021
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    The hydraulic ram on the front of the plow truck (a 2020 International HV) won't lower - and it's the only hydraulic on the entire valve assembly that isn't working.

    It's not a problem with the electronic controls, I've tested those and put a wrench on the manual control, and the "Raise" part of the double-action valve works (it's hydraulic raise, gravity lower). It's already raised all the way, but I can hear it working and the pressure jumps on the gauge.

    Any suggestions to this non-mechanic?

    Here's a picture of the hydraulics on the hoist, and the valve assembly, with the raise/lower for the front plow highlighted:

    TruckFrontHoist.JPEG TruckHydraulics.JPEG
     
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  3. 062

    062 Road Train Member

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  4. AModelCat

    AModelCat Road Train Member

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    With a double acting cylinder I wouldn't think it'd use gravity to lower. You'd normally see a single acting cylinder in a case like that.

    You said you can manually override the control valve to raise it, can you manually override it to lower it? That'd at least prove the main part of the hydraulic circuit is functional.

    How did you test the electrical side of it?
     
    062 Thanks this.
  5. Ridgeline

    Ridgeline Road Train Member

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    Sounds like it is a cartridge (spool) problem, or a solenoid problem ... or both. These are rebuildable and not bad costly wise.
     
  6. JB7

    JB7 Heavy Load Member

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    upload_2025-6-6_23-8-54.png

    Manuals

    Check with Henderson about a service manual. They don't say on the website if the manuals are parts or service or both. Parts manual diagrams can give a lot of good info.
     
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