Forum › Forums › Tractor Troubleshooting › Loader drift
- This topic has 13 replies, 7 voices, and was last updated 10 years, 5 months ago by Tinbender.
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June 15, 2013 at 2:27 pm #30782
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.
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June 15, 2013 at 6:51 pm #36140
My guess is that you have one or both curl cylinders bypassing. Simple to rebuild them and not expensive, either.
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June 15, 2013 at 8:48 pm #36141
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?
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June 15, 2013 at 9:43 pm #36142
The two cylinders are plumbed in parallel. If one is bypassing, fluid will leak from the other through it.
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June 15, 2013 at 10:52 pm #36143
I thought of that after I posted. Is there anyway to tell which one is bypassing without rebuilding both of them?
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June 16, 2013 at 8:18 am #36144
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?
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June 16, 2013 at 1:47 pm #36145
Like Rich said, but another thing to consider is that these valves do not have load checks, so it could be either.
Account deleted.
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June 17, 2013 at 1:23 am #36148
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
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June 17, 2013 at 4:51 pm #36150
Thanks for the detailed instructions. Where would I get plugs that would fit metric hoses?
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June 27, 2013 at 5:13 pm #36165
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
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June 28, 2013 at 6:51 pm #36166
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.
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July 2, 2013 at 10:59 am #36170
Len10
I'll most likely rebuild the cylinders by this weekend depending on the weather. It has been raining every day here.
Lenbo
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June 21, 2014 at 4:08 pm #37055
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.
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June 21, 2014 at 6:08 pm #37056
But is it still raining? 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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