Hydraulic fluid squirts out vent

Forum Forums Tractor Implements Hydraulic fluid squirts out vent

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    • #30803
      ironhorsemike
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        I normally lower 3-pt and FEL before shutting off engine.  Today, I shut it off, then lowered 3-pt.  No problem.  When lowering FEL, hydraulic fluid shot out of vent pipe of filler plug behind seat, enough to cover rear end of tractor and drip to ground. Fluid continued to run for a few seconds after lowering stopped.  When I tried lowering it very slowly a bit later, it squirted again.

        This happened one time last year, but has never done so with engine running.

        Last time I checked / added fluid, several weeks ago, it was at the dipstick line.

        Any ideas what's happening here?  Thanks.

      • #36327
        RichWaugh
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          With the cylinders extended, when you shut off the engine, the fluid had nowhere to go except to the sump and out the vent.  You need the engine turning the pump in order to circulate the fluid around to the other side of the cylinders.

        • #36329
          ironhorsemike
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            Thanks for your explanation, Rich.  It makes perfect sense as I think about.

            I have been puzzling since you wrote, that this loss of fluid has occurred only twice now in the time I've owned the tractor, even though there have been a good number of times I've lowered the FEL with the engine off.

            The only answer I can come up with is that the system had been low on fluid all that time and there was room for it in the sump as it left the cylinders with the pump off.

            Does this sound plausible?

          • #36330
            RichWaugh
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              Yes, it does.  Particularly if you were maybe checking the sump level by screwing the dipstick back in – screw-in dipsticks are supposed to be read by just setting them on the hole, not screwing back in.  That makes a gallon or more difference in the level.  Been there, did that.  Another possibility is doing it on sloped ground.  If the tractor is pointed just a bit downhill it leaves the vent much clearer for fluid.  If pointed uphill, it can eject fluid even with the engine running.  Some owners have extended the vent up a tube along the ROPS to overcome that problem if they have steep terrain to deal with.

            • #36341
              ironhorsemike
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                Been offline a few days, so I didn't see your latest, Rich.  Thanks for clearing up how to read a screw-in dipstick.  I always wondered about that and had been doing it the wrong way, by screwing it all the way in.  But wouldn't incorrectly screwing it all the way in to read the level tend to under fill it?

                And here's what I think part of my problem was too:  I had last filled my sump as the tractor sat out in the field for days as I worked on that injector pump problem.  I had the FEL all the way up to get the side arms out of the way of the engine compartment.  With the rams all the way extended when I filled the sump, they had a greater volume inside them than when they are down.

                Is there a general rule about what position hydraulic cylinders should be in when you check and fill the sump?

              • #36345
                RichWaugh
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                  Yes, screwing in the dipstick will give a false reading that will have you under-filling the sump.

                  When the tractor is shut down, you should retract all cylinder, i.e., lower the bucket to the ground and have it curled up, bring the backhoe boom in to rest with the bucket opened out, not curled as for transport (this assumes your bucket cylinders are retracted in the configuration), and the outriggers fully retracted.  All the hydraulics movements should be done with the engine running so that fluid is pumped around to the other sides of the pistons.

                  If you have the loader raised and turn off the engine and then lower the arms, you'll push a lot of fluid back to the sump with nowhere for it to go, since the fluid from the other side of those pistons has already been pumped back to the sump.  So lowering the arms with the engine off will cause the fluid to squirt out the sump breather.

                  These are open-center systems so you fill the sump with all the cylinders retracted properly so volumes are at equilibrium in all the cylinders.

                • #36347
                  lenbo
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                    Rich

                    good info for anyone not familiar with the screw in dip sticks and position of the cylinders.hailking

                  • #36350
                    ironhorsemike
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                      Got it, Rich.  Thanks again.

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