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ram losing pressure?

Discussion in 'Western Plows Discussion' started by leeddog65, Nov 24, 2015.

  1. leeddog65

    leeddog65 Member
    Messages: 85

    I have an ultra mount mvp V plow, and while in transit, Ill notice the ram is slowly dropping, also doesn't have the same power when under load.

    Cant seem to stack snow like it used to, any ideas?
  2. dieselss

    dieselss PlowSite Fanatic
    Messages: 11,392

    Is it leaking anywhere?
  3. mishnick

    mishnick 2000 Club Member
    Messages: 2,353

    The leaking down problem is a valve allowing fluid to leak back to the reservoir. The power issue is probably electrical or a tired motor. Check for loose / dirty connections on the switched motor power cable. Look at the relay / solenoid under the hood on the plow motor + wire. Check for voltage drop under load if you know how.
  4. leeddog65

    leeddog65 Member
    Messages: 85

    Not leaking anywhere, as for voltage, not so much, but I guess its probably time to learn, I will check all connections though
  5. mishnick

    mishnick 2000 Club Member
    Messages: 2,353

    When I say valve leaking down I don't mean leaking out.... When a valve leaks internally there will be no fluid on the ground. The valve / valves that hold up the plow have check valves built in so that when they close absolutely no fluid can flow backwards across the opening. This is what keeps your blade up under pressure. If a bit of dirt gets in the valve it can hold it open enough to allow fluid to leak out of the lift ram and flow back to the reservoir the same as if you hit the down button only slower. Sometimes you can just pull the valve, put power to it to hold it open and then blow through with compressed air to dislodge a bit of dirt but in most cases the valve is bent, swollen or damaged in a way that is not reversible. Check out this link on page 20:
    Valves S1 and S3 are the two that could be to blame. This diagram shows physically where they are located on the valve body. Page 37 and up shows the hydraulic schematics and flow paths for the various functions. S1 is the most likely problem but sometimes S3 is guilty.

    As far as the electrical troubleshooting for the "slower than it used to be" issue. That link has electrical schematics too. We can talk you through some testing if you can understand the instructions and have the tools. You will need, at the very least an analog test light. (That means it has a regular incandescent bulb, not an LED) Better if you also have a multi-meter capable of voltage and resistance. Even better if you have, or can borrow, a meter with a clamp-on DC current probe capable of 200 amps. Let us know if you have any of this stuff and if you know how to use them and we will go from there.