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Pressure relief on skid

Discussion in 'Heavy Equipment' started by WIPensFan, Jan 14, 2013.

  1. WIPensFan

    WIPensFan PlowSite Veteran
    Messages: 3,468

    I've got a 2010 Bobcat S650 with a 10' Snow Wolf plow on. The plow itself has a pressure relief valve on it. This has happened 2x where I take the plow and hoses off and then when I go to hook it all back up, there is pressure on the plow side and I can't get the hoses back on. Both times I've done what Bobcat says and pushed in on couplers for 5 sec before taking them off, but it doesn't seem to matter. The valves on the Bobcat side are free to move. I know it's plowside because the fix is to loosen one of the hoses at the pressure relief valve on the plow. As soon as I do that, the hoses hook right up. Do I need to have the Aux Hyd. button off before I disconnect, or some other routine to follow? I think I have but not sure.

    Any help would be appreciated. Thanks.
  2. jomama45

    jomama45 PlowSite.com Addict
    Messages: 1,172

    The best insurance is to hook the plow side connectors together EVERY time you take them off. The fluid gets very warm during use and creates pressure. As it cools, you'll have an unbalanced pressure from one side to the other, making it hard to get the connectors to open up. It also helps keep the connectors clean and free from corrosion............
  3. WIPensFan

    WIPensFan PlowSite Veteran
    Messages: 3,468

    That's a good idea but corrosion is not an issue, it's kept inside and wiped off everytime I disconnect them. I have never tried to hook them together after taking the plow off, but I will try next time. The only thing is, if there is pressure in there they will not hook together. The last time I took it off, I hadn't been using it, so the fluid temp should be room temp.

    Thanks for the advice, I will try it.
  4. peteo1

    peteo1 PlowSite.com Addict
    Messages: 1,658

    Try this,

    When you are done with the machine shut it off. Turn key to "on" position and work the levers, pedals and auxiliary hydraulic switches. What's happening is you are leaving pressure in the attachment and by disconnecting the fittings you're trapping that pressure in the lines. I've had to do that with certain attachments but not with others. Not sure why that is but when you cycle the hydraulics with the key on and engine off it seems to do the trick.
  5. alldayrj

    alldayrj PlowSite.com Addict
    Messages: 1,097

    My excavator attachment used to do that too. I always turn the machine off and hook the lines together
  6. WIPensFan

    WIPensFan PlowSite Veteran
    Messages: 3,468

    It has no key, all push button. My old machines I would hold the key to the left for 5 sec when shutting them off.
  7. WIPensFan

    WIPensFan PlowSite Veteran
    Messages: 3,468

    If I turn the Aux Hyd. off when running and then toggle the switch that angles the plow left and right, would that relieve pressure?
  8. Grassman09

    Grassman09 2000 Club Member
    Messages: 2,806

    In my Cat there is a button for that very problem. Dealer said it sucks back fluid into the machine.. Ok.. Surprised your machine does not have that being a 2010. That should work, working the functions with the machine of. Works on my tractor that way.
  9. tread lightly services

    tread lightly services Member
    Messages: 89

    this is the best advice, i always hook them together then throw some oil like wd-40 on them
  10. Antlerart06

    Antlerart06 PlowSite Veteran
    Messages: 3,437

    Tap the ball on the hose on the plow cpl time to relive pressure from the hose Watch out might be some oil flying out
    I have do this to my field Disc few times
  11. WIPensFan

    WIPensFan PlowSite Veteran
    Messages: 3,468

    Don't know if the machine has a similar function, but that would be nice. Might have to read the manual.

    What ball?
  12. peteo1

    peteo1 PlowSite.com Addict
    Messages: 1,658

    Yes, just do it with the engine not running. If I remember right bobcat has a red on button and a green start button right? Just turn the battery on but don't start and toggle the switch like you said
  13. WIPensFan

    WIPensFan PlowSite Veteran
    Messages: 3,468

    If I remember right ( that's a big if lately ) and I was just in it today :dizzy: Run is yellow, Start is green and Stop is red. Really only couldn't remember if Run was yellow. Anyway, hit Run button, that preps for starting like turning key half way on, then toggle switch back and forth? Just didn't know if those switches were even active at that point.
  14. Antlerart06

    Antlerart06 PlowSite Veteran
    Messages: 3,437

    You said plow side has pressure reason you cant hook back up
    on end hydro line fitting coupler is a ball push it
    It will release the pressure on plow side

    Maybe Im reading it wrong
  15. White Gardens

    White Gardens 2000 Club Member
    Messages: 2,665

    I'd suggest the same thing, but he probably has the flat-faced couplers on his rig.

    I get the same symptom with the plow on my truck and central hydro system. I have the ball style couplers and do this method to release the pressure to get them to hook up.

    Old farm boy trick. Thumbs Up

  16. WIPensFan

    WIPensFan PlowSite Veteran
    Messages: 3,468

    Yes, flat face couplers. They got no balls.;)
  17. jomama45

    jomama45 PlowSite.com Addict
    Messages: 1,172

    I think alot of folks are trying to confuse you................:)

    You said you're confident that it's a plow side issue, so there's no need to mess with the machine side if they're loose.

    I had this problem regularily in the past as well, to the point that I'd have to be absolutely confident I was done with the plow for the day before dropping it to attach the bucket. Someone here (I think JD Dave) told me to latch the 2 together, and explained why it happened, and I've never had the problem since.................

    Also, if you take the hoses off in the field frequently, I'd suggest carrying a small bottle torch, or big lighter with you as well. Eventually, you're going to have the couplers freeze up with ice when you need to remove them...........
  18. WIPensFan

    WIPensFan PlowSite Veteran
    Messages: 3,468

    I was just hoping I could draw some pressure off the attachment from the machine before disconnecting. I am going to put them together next time it comes off, which won't be this week because we are supposed to get some snow Wed.

    This situation makes me not want to switch to the bucket though, knowing reattaching the plow will be an issue.

    Thanks for all the help everybody.Thumbs Up
  19. peteo1

    peteo1 PlowSite.com Addict
    Messages: 1,658

    The other option is to take two big crescent wrenches with you and crack the fittings open a little to relieve the pressure. Kind of messy though.
  20. SnowWolf

    SnowWolf Sponsor
    Messages: 59

    WIPensFan - if the suggested solutions for relieving the pressure in the plow hoses before disconnecting do not work, you can also purchase couplers called "Connect Under Pressure" from a local hydraulics supplier. Probably one of the other suggestions above will work, but this will fix it if not.