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?? Purging air from the hydraulics ??

Discussion in 'Commercial Snow Removal' started by Roger Dodger, Oct 28, 2003.

  1. Roger Dodger

    Roger Dodger Senior Member
    from nw Pa.
    Messages: 240

    In the past it's just been drain the reservoir and refill. I was thinking about draining all three cylinders/hoses as well for a complete system flush. However, is this worth it in the end with having to purge the air introduced into the system? Perhaps just changing reservoir fluid is fine for the most part so I don't jazz things up and create a monster for me to deal with?
  2. Brian Simmons

    Brian Simmons PlowSite.com - Sponsor
    Messages: 196

    Roger Dodger,
    You should do a complete flush especially since you have not done one in a while. Draining just the reservoir will not get the contaminants in the rest of the system. All you are doing is diluting the good oil with the old oil. Most plows will hold almost a quart in the cylinders and lines, so theoretically you are only changing half the oil. As you know getting the air out sometimes can be a pain but is well worth it in the long run. The fastest way to get all of the air out of the system is to get the rear of the angle cylinders(where the port is)higher than the front. This means getting the truck up on a few boards or on a curb so that the blade is lower than the truck. I know you already know this but we get a lot of calls from newbies that do not.

  3. wyldman

    wyldman Member
    Messages: 3,265

    If your careful when flushing,you should not get much air in it.Lift the plow slightly off the gound,and place a jackstand under the a-frame,so the plow is a few inches off the ground.Collapse the lift ram,and drain and refill the reservoir first.Remove both angle hoses at the rams and run the plow to flush out the fluid until it comes out nice and clean.Keep the reservoir topped up so it doesn't suck air.Keep the hoses level with the pump,so they don't drain or suck in air.Manually move the plow back and forth to expel all the old fluid from the rams.Compress one ram and then connect that hose.Use the plow controls to extend the ram,and it will fill with fluid.Repeat for the other side.Never let the fluid run dry.Top up the reservoir,lift the plow,and remove the jack stand.You can now cycle the plow up\down and left\right to purge any remaining air.Top up the fluid again and your done.

    Now would be a good time to replace the hoses too,and keep your old ones as spares.Use a good 2 wire hydraulic hose,not the off the shelf replacement hoses,they will hold up better.
  4. Big Nate's Plowing

    Big Nate's Plowing PlowSite.com Addict
    Messages: 1,266

    I agree on an actual steel reinforced hose from a good hydraulic shop, they hold up better and have a thicker jacket to keep the hoses a little warmer then the ambient tempature. another plus is that you can get high flow fittings that flow a few more cubic inches of fluid a minute and it helps some with angle speed
  5. micah79

    micah79 Senior Member
    Messages: 303


    Will the hoses have the right fittings on the ends?
  6. wyldman

    wyldman Member
    Messages: 3,265

    Most of the fittings are all standard sizes,and they should know what you need.Take you old stuff so they can match it up just to be sure,and they will custom make the hoses while you wait.I usually tell them to go a few inches longer on the hoses,so they don't get pulled as tight when the plow is all the way down.

    Be careful and make sure the fittings are the same,or of better quality.The cheaper fittings will sometimes snap off.Parker is a good brand name to ask for.The fittings should also be the same length,so they won't contact anything and get busted off.
  7. micah79

    micah79 Senior Member
    Messages: 303

    Thanks, Chris

    Now I just need to find someone locally. I'll make some calls tomorrow.
  8. Crash935

    Crash935 2000 Club Member
    Messages: 2,377

    Always angle the plow before lifting when doing a fluid change, this will keep the pump from cavitating and intoducing more air into the system. If air is a problem, angle the blade to one side, after the blade stops continue trying to angle the blade for a few seconds, repeat for the other side. This runs the pump over relief and forces the air back to the tank.