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Back Blade Won't Go Down

Discussion in 'Truck & Equipment Repair' started by QuadPlower, Dec 2, 2008.

  1. QuadPlower

    QuadPlower PlowSite.com Addict
    Messages: 1,056

    When I bought the truck the back blade didn't go down. I figured it was something easy. Its not. I need some help.

    Here's what i got.

    3-way toggle switch in the cab. Electric/hydraulc up under the hood with a solenoid to activate the pump and two electromagnetic valves in the pump houseing. Hoses run back to a 2-way cylinder. There are quick connect at the bumber to remove the back blade.

    Power from the battery runs to one side of a solenoid on the motor. Power wire runs in a Green wire from there to toggle switch. White wire on one side of switch runs up to a valve solenoid on the pump. Black wire on other side of switch runs to another valve solenoid on the pump.

    When the switch is pushed one way the White wire powers the solenoid and a Green wire powers the solenoid to turn the pump on. The pump runs and the cylinder goes up.

    When the switch is pushed the other way the Black wire powers the other solenoid on the pump and the Green wire powers the solenoid to turn the pump on. The pump runs and the cylinder goes up.

    There is no power on the opposite wire when it is switched the other way.

    I have checked the valve solenoids and they both work like an electro magnet.

    The only way to lower the cylinder is to crack open the line and bleed off the fluid.

    Any ideas?
     
  2. elite1msmith

    elite1msmith 2000 Club Member
    from chicago
    Messages: 2,762

    well first you need to break down the problem ,

    Is this an electrical problem , a hydro problem , or a mecahnical problem?

    rule out the mechanical problem first... visually inspect to make sure the plow isnt jammed or binding up. inspect the packing nuts on the hydro ram , they can jam up

    next rule out the hydro system. apply positive power using a jumper wire, to each mag soilonoid , and verrify that the coil is becoming magnetic. I assume that because the pump raises the plow , the pump soiliod is also good. (but you could check it, genrally)

    with the plow raised, if you apply power to one of the coils , the plow should fall. Keep in mind rear plows are on the lighter side, so it might take some added weight on the plow to allow it to gravity fall



    next check the electrical , take a test light , and ground the alligator clip , and use the point end to stab the wires.... check main power (constant) check each valve when the switch is moved, and check the motor soilnoid tigger wire, when the switch is moved IN BOTH DIRRECTIONS, since this plow powers up and down.

    then put your alligator clip on the positive battery , and check that your coils also have a good ground to them .
     
  3. QuadPlower

    QuadPlower PlowSite.com Addict
    Messages: 1,056

    Thanks for the input
     
  4. elite1msmith

    elite1msmith 2000 Club Member
    from chicago
    Messages: 2,762

    Are you saying that you switched the hoses at the pump , and now the blade will power down in any position that you push the switch?


    your coils have a ground because they are magnetic, more than likely

    i would say your valve is bad
     
  5. QuadPlower

    QuadPlower PlowSite.com Addict
    Messages: 1,056

    I will see if I can buy one today.
     
  6. QuadPlower

    QuadPlower PlowSite.com Addict
    Messages: 1,056

    I finally got around to fixing this problem.

    On the hydraulc pump that runs the back blade cylider there are two valves. The larger 4 way-2 position valve was broken. I had NAPA order one and when it came in I replaced it in the parking lot. The normal cost of the part is $72, but since my buddy works there he gave me a discount and only charged me $52.

    WOW is all I can say about the back blade. I went out right afterward and cleaned my driveways. It works great. Down pressure removes any tire tracks that might have built up. I hand shovel the snow away from the garage doors and back up, pull the snow out, and then push it in the front yard with my V-blade.

    This is the first time I have used a back blade and I will not have another truck without one.
     
  7. no lead

    no lead PlowSite.com Addict
    Messages: 1,308

    here we go!