Loader drift

Forum Forums Tractor Troubleshooting Loader drift

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    • #30782
      Len10
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        After doing some heavy work, the FEL started to drift from the curl to the dump position.  Within a few minutes it can go from the fully curled position to the dump position.  I can still do work with it as the curl-dump function still works. The lift function works normally with a drift over weeks not minutes, which I think is normal.  I assume the problem is in the control valves. What would be the best trouble shooting sequence? The FEL by the way is a Chinese loader.  The manual states it is a Farmstar series loader. I think the model number is LDJM254K for what ever that is worth.

      • #36140
        RichWaugh
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          My guess is that you have one or both curl cylinders bypassing.  Simple to rebuild them and not expensive, either.

        • #36141
          Len10
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            If one cylinder was bypassing, wouldn't the other cylinder be able to hold the empty bucket in the curled position? What's the likelihood that both cylinders would start bypassing at the same time? 

          • #36142
            quicksandfarmer
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              The two cylinders are plumbed in parallel. If one is bypassing, fluid will leak from the other through it.

            • #36143
              Len10
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                I thought of that after I posted. Is there anyway to tell which one is bypassing without rebuilding both of them?

              • #36144
                Len10
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                  I still don't fully understand how drift works when a cylinder is bypassing (internally leaking).

                  According to an explanation here “when a load is hanging on a double-acting cylinder…the volume of pressurized fluid on the rod side can be easily accommodated on the piston side. But as the cylinder creeps a vacuum will develop on the piston side – once again due to the unequal volumes – and depending on the weight of the load, this vacuum may eventually result in equilibrium that arrests further creep.”

                  In my case an empty bucket will drift from the fully curled position to the dump position without reaching equilibrium. Can the cause of drift still be an internal cylinder leak?

                • #36145
                  Bob Rooks
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                    Like Rich said, but another thing to consider is that these valves do not have load checks, so it could be either.

                    Account deleted.

                  • #36148
                    ronjin
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                      Len10,

                      Here is the technique that I used to check the possible leakage on my FEL cylinders.

                      1. Raise the bucket about 3 feet off the ground with the bucket level with the ground.

                      2. Block up the bucket to hold it in that position. I used a combination of a 4×4 and a floor jack.

                      3. Turn off the tractor and wiggle the FEL controls to release any pressure in the lines.

                      4. Remove and insert plugs into all of the hoses that feed the FEL cylinders.

                      5. Remove the blocking from under the bucket.

                      6. Use a ruler to measure height from the ground to both the back and front of the bucket.

                      7. Leave it that way and periodically remeasure both the front and the back height of the bucket also record the times.

                      This takes the FEL control valve out of the picture and should give you some data points to determine whether there is leakage in the cylinders, how much and whether it is both tilt and/or lift cylinders.

                       

                      If it is leaking down then isolate by plugging one cyl at a time. When they are connected to the valve the cylinders are tied together so it only takes one bad cylinder and it will leak down.

                       RonJ

                      ronjin

                    • #36150
                      Len10
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                        Thanks for the detailed instructions.  Where would I get plugs that would fit metric hoses?

                      • #36165
                        lenbo
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                          Len10

                          I had the same problem for quite a while with my FEL Z30. Ron gave me the same instructions at that time. Thanks Ron!

                          Recently I was helping my neighbor put in a driveway and the truck drive accidently lost 12 ton of the load in one place. I tried to get as much as possible as fast as possible moved to a different area. I blew a hose connection on the FEL, got that fixed, finished the project, the next time I went to use my tractor to move some dirt for a concert pad at my house the FEL bucket curl dropped and would not hold up. I ended moving the dirt by wheel barrow. So much for helping out neighbors. I am currently rebuilding all four cylinders and put another post on that subject today. I got the cylinder kits from Jerry at Affordable tractor.

                          I'll be rebuilding by next weekend.

                          LenBo

                        • #36166
                          Len10
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                            LenBo

                            I'm looking forward to your new thread.  I haven't had a chance to 

                            play with work on the tractor recently, but I hope learn from your posts when I start to rebuild my cylinders.

                          • #36170
                            lenbo
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                              Len10

                              I'll most likely rebuild the cylinders by this weekend depending on the weather. It has been raining every day here.

                               

                              Lenbo

                            • #37055
                              Len10
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                                I've been negligent as I never posted a follow up. Like usual Rich Waugh was right. One Cylinder was bypassing. One of the seals was badly mangled. Replacing the seals was a quick easy task. Thanks everyone for your help.

                              • #37056
                                Tinbender
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                                  But is it still raining?roflmao  Seriously, thanks for letting us know how it turned out. It can save hours of diagnosing and dollars when you're up against something for the first time knowing how the problem was fixed by someone else.

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