Test the cylinders by removing the cap end hose(s) and plugging it. Pressurize the cylinder in its retracted position. If it extends the seal has gone and needs replacement. if not move onto another component. The cylinder should extend faster, be weaker on extension and retraction should be weaksauce and slow possibly followed be a slight extension at full retraction after being under pressure.
Weak curl function
- Thread starter RNeumann
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DavesTractor
Elite Member
Well I would loan it to you, but I'm not sure how I would then test tractors. It's a small detail!
Always thought it was amazing how heavy gold is. Not that I have an ounce, let alone a pound.
LD1
Epic Contributor
Sounds like a valve issue if swapping hoses made the issue go to the lift.
ning
Elite Member
I think Dave's point is that curling 1200# that's in the bucket (6-12" from the pivot point) is a lot easier than curling 1200# which is centered 24-30"+ away from the pivot point. Curl strength is probably measured at the cutting edge of the bucket and will drop the farther away you get.
Looking over the thread, I don't see what you're trying to curl - where/how heavy.
Looking over the thread, I don't see what you're trying to curl - where/how heavy.
LD1
Epic Contributor
On most loaders, the curl at the bucket edge is indeed stronger than lift.
However, due to the geometry, at some point forward of the bucket edge, the loader power overtakes the curl.
They both diminish in their lifting capacity the further forward you go, but the curl diminishes much quicker.
ITs different on every loader. It may be 12" forward, it may be 12' forward. But rest assured, at some point, the loader lift capacity will be greater.
However, due to the geometry, at some point forward of the bucket edge, the loader power overtakes the curl.
They both diminish in their lifting capacity the further forward you go, but the curl diminishes much quicker.
ITs different on every loader. It may be 12" forward, it may be 12' forward. But rest assured, at some point, the loader lift capacity will be greater.
DavesTractor
Elite Member
I was hoping you would chime in on this. Well said.
DavesTractor
Elite Member
The curl was weak when lifting a rock way out on the forks. He could lift but not curl. He then switched hoses some time after removing the forks and putting the bucket back on. He then tested the bucket in heavy clay and the bucket and was able to curl, but not lift. I propose that nothing changed by swapping the hoses. It only appeared to change, because of a lack of understanding of the leverage involved. I say that humbly, as I have not run any calculations on it and I am engineering by the seat of my pants. And I may not fully understand his testing, so my apologies if I am making assumptions that are not true.
This has been a good thread, it makes us think a little.
LD1
Epic Contributor
I missed where he said he was trying to fork a rock way out. Also missed where he tested after swapping hoses on a bucket of thick clay.
Looking back, I still don't see where he said that. Am I just overlooking something, or what?
Looking back, I still don't see where he said that. Am I just overlooking something, or what?
OP
RNeumann
Elite Member
This post must have been written in invisible in. Not trying to be rude but I do want to be blunt. I understand geometry and I understand how to test functions. I didn't just run one test with 3' forks and say the curl was weak and then switch to a 14" bucket and suddenly say curl is now strong. This post has digressed into a completely different topic by some.
I replaced both QDs that are in the curl circuit. The old ones looked fine- no derbies that I could see. I am not noticing the weak curl but honestly most of what I did today was grapple work ahead of the rain. The little bit of clay I did move had all functions working per normal (no weak curl). Had I found a big chunk of something in a QD I'd call it good and move on.
Is it normal to have a QD fail and not find/see the problem with it?
Since I didn't I will test the cylinders.
When testing the cylinders should I have a load on the bucket of forks? Or just the weight of the bucket?
Thanks for the advice.
DavesTractor
Elite Member
Sorry about that, he has another thread about this exact issue in the Mahindra section. It fills in the gaps a little. Gives some pictures, etc.
DavesTractor
Elite Member
I think you may feel I am being critical of you, trust me I am not. This kind of stuff is interesting. I did respond to this thread with some info from your other thread, and that confused those that had not read both threads. The other thread has the pictures of the rock on the pallet, and the firewood, etc.
Anyway, for what it's worth, I'd suggest once you work through all your current testing and if you are still not satisfied that the tractor performs as it should, it would be nice to put some gauges on and see if the cylinders are getting proper pressure. (Maybe you have done this, I did not read back through this evening) If so, do a lift test with a pull scale and see if the lift and curl are at spec. If you have proper pressure and lack proper lift, I'd suspect a cylinder leaking by internally. Bumgravy is giving good advice on testing the cylinder.
Typically a QD that is malfunctioning and barely opening will make that circuit really slow. Or more often, one side or the other of the QD quits flowing altogether and that circuit just doesn't work. If the speed of the curl/tilt seemed near normal, then I doubt it was a bad QD. And flow = speed, pressure = power. So as long as the QD was flowing even a reasonable amount, the same system maximum pressure would get to your tilt/curl rams and it would lift the same amount, albeit more slowly. It may take longer if flow is restricted, but the pressure would still be there.
Best of luck on this, and thanks for keeping us informed. If you feel I am pulling this off topic and nothing said has been useful or helpful, just let me know and I'll bow out of trying to assist with this issue. I won't get my feelings hurt.
Sometimes I'll explain something thoroughly in a post not because you as the OP don't know it, but because a lot of folks read these forums and can gain knowledge from our experiences.
BrokeFarmerJohn
Veteran Member
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- 2017 Mahindra 5555, John Blue G-1000, Massey Ferguson 98, John Deere GP
Mine does something similar to what the OP describes, I have a load on my pallet forks on my FEL and it can lift it but can only curl it about 1/2-3/4, if I lift higher it will relieve enough pressure to curl it the rest of the way.
I don't think I have a problem though, like others have said the weight I'm curling is a long ways (up to 4ft) from the pins.
The bales are over 1000lbs, prob closer to 1200lbs, that one in the pic is a tightly packed 4x6 round bale.
I don't think I have a problem though, like others have said the weight I'm curling is a long ways (up to 4ft) from the pins.
The bales are over 1000lbs, prob closer to 1200lbs, that one in the pic is a tightly packed 4x6 round bale.
OP
RNeumann
Elite Member
I think you may feel I am being critical of you, trust me I am not. This kind of stuff is interesting. I did respond to this thread with some info from your other thread, and that confused those that had not read both threads. The other thread has the pictures of the rock on the pallet, and the firewood, etc.
Anyway, for what it's worth, I'd suggest once you work through all your current testing and if you are still not satisfied that the tractor performs as it should, it would be nice to put some gauges on and see if the cylinders are getting proper pressure. (Maybe you have done this, I did not read back through this evening) If so, do a lift test with a pull scale and see if the lift and curl are at spec. If you have proper pressure and lack proper lift, I'd suspect a cylinder leaking by internally. Bumgravy is giving good advice on testing the cylinder.
Typically a QD that is malfunctioning and barely opening will make that circuit really slow. Or more often, one side or the other of the QD quits flowing altogether and that circuit just doesn't work. If the speed of the curl/tilt seemed near normal, then I doubt it was a bad QD. And flow = speed, pressure = power. So as long as the QD was flowing even a reasonable amount, the same system maximum pressure would get to your tilt/curl rams and it would lift the same amount, albeit more slowly. It may take longer if flow is restricted, but the pressure would still be there.
Best of luck on this, and thanks for keeping us informed. If you feel I am pulling this off topic and nothing said has been useful or helpful, just let me know and I'll bow out of trying to assist with this issue. I won't get my feelings hurt.
It's not that I think you are being critical- it's that you have side tracked the thread......until this post! My first post was about how to diagnose the curl circuit- I got a few great responses. Then I post about replacing QDs- the next post (yours) is about pallets (no mention of QDs). Then your next post is about bars of gold. Then thanking LD1 for chiming in. Then after I post that I replaced the QDs you say it's probably not the QDs.
I know you and others have a lot of good information. It just seems like on this one the info was hard to come by.
I've got some great info here about diagnosing the circuit. Switching the lift and curl QDs was an easy test- and a great idea!. Isolating the cylinders and doing a bleed down will also be fairly easy to do- I will need a few SAE caps- unless someone has an easier way????. The last would be the valve. I don't know how to test that other than what I described where I placed my pressure gauge on the valve discharge and everything read 2200psi at idle and didn't change with RPM- I'm assuming that's normal pressure regulator function????
DavesTractor
Elite Member
Gotcha, no problem. I guess I am not convinced you have tested adequately to really know you have a problem. I think what you are describing (weak curl in certain situations) is normal. I'm still not convinced that leverage issues aren't the main problem. But it could be that you have a pressure issue, where your relief is set a little low, so we will go down that path.
You will need to get the specs and test. I don't have a book in front of me to see what the specs are, but generally small tractor system reliefs are in the 2100-2400 range, depending on the model. You will need to know more specifically what your tractor is designed for. 100 psi can make a noticeable difference in lift capacity. See if your tractor manual has any specs in it for system pressure and also check your loader manual for it's system pressure. They are often different. Or call your selling dealer and get that info if it is not in the operators manual. The loader valve will likely have a separate relief from the tractor relief. No matter what you do to the loader relief adjustment, it will never allow more pressure than the main tractor system relief, because that relief is prior to the loader. So I'd find the numbers first.
OK, I am making up these numbers, so be clear on that. It is for an example, don't use them. Let's say the tractor relief is supposed to be 2350 psi and the loader is supposed to be 2325 psi - and you are reading 2200 at the loader. Put the gauge back into a loader working port directly or T it into the tilt/curl or lift system. If you T it, you then need to bottom out a cylinder to see the pressure. Adjust your loader valve relief slightly (tighter) and test again. If you gain nothing, then your system relief is set low. If you gain something, go ahead and take it up to the designed system pressure for the loader - and you are done. If the system pressure is low, contact your dealer for how to raise it.
For the sake of others, let me remind folks that you can break expensive things or hurt yourself messing with pressure reliefs if you do not have a gauge and knowledge of the specs and some experience with this sort of thing. A dealer can do this for you in less than an hour.
As far as pressure vs RPM, its pretty basic hydraulic knowledge that an open center hydraulic system with a gear pump that rpm just gives you more flow, not more pressure. It speeds things up. Yes you can spill a little over the relief with high rpms for a moment, but absent that in an open center system the pump just flows oil, pressure is made when you obstruct the flow. So you will see the pressure relief opening at the same pressure at 600 rpm or 1600 rpm. Make sure you understand things well enough to not break something or hurt yourself.
OP
RNeumann
Elite Member
Thanks for the info. The big take away was in your first paragraph when you said "in curtain situations". It's never been only sometimes or in curtain situations- I'm assuming this was the miscommunication. I first noticed it with the bucket trying to move plane old road base. I'd go into the pile with the bucket and it would lift but wouldn't curl- I've never been on a machine that acted that way. The Mahindra forum confirmed that others were NOT experiencing that type of function. I've operated several other tractors- I've never seen a machine that wouldn't curl but would lift with the bucket in a pile of dirt or base.
As far as the diagnosis side of things- yes that was my original question in this post- how to diagnosis the curl circuit. I believe (but not 100%) the "factory" setting is 2100psi for the 1538- I'm making 2200psi (both curl and lift and I didn't adjust it).
Like I said above from my limited use it appears to be better- uncoupling and recoupling and QD replacement. However, I want to verify everything at this point.
I believe the next step is testing the cylinders. This process described here seems like it would work-
Bypass testing a hydraulic cylinder - YouTube
With this method I'm assuming I need to isolate the two cylinders from each other. Logistically is that correct or am I missing something with regards to this type of two cylinder circuit (not opposing like a snow plow)?
DavesTractor
Elite Member
That's a good youtube video. I suppose you could test both at once as long as you cap both. Don't cap just one and try testing it with the other in the loop.
If this lack of curl is not just in certain (or curtain as you say, ha, ha) situations and you have poor curl loading road base from a pile, you might very well have a cylinder bypassing. It will be interesting to see the result. If all is good but you want more, you can do as Mike did with his tractor and install slightly larger curl cylinders. An 1/8" or 1/4" diameter difference makes a lot of difference in power, and slows the cylinder down commensurately. I doubt a slower curl would be a problem as they are pretty quick already. You just become your own warranty center if that causes an issue. If you do that, you must make sure the cylinder otherwise specs out pretty much exactly or you can bend parts.
If this lack of curl is not just in certain (or curtain as you say, ha, ha) situations and you have poor curl loading road base from a pile, you might very well have a cylinder bypassing. It will be interesting to see the result. If all is good but you want more, you can do as Mike did with his tractor and install slightly larger curl cylinders. An 1/8" or 1/4" diameter difference makes a lot of difference in power, and slows the cylinder down commensurately. I doubt a slower curl would be a problem as they are pretty quick already. You just become your own warranty center if that causes an issue. If you do that, you must make sure the cylinder otherwise specs out pretty much exactly or you can bend parts.
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nosurprise
Silver Member
That's a good youtube video. I suppose you could test both at once as long as you cap both. Don't cap just one and try testing it with the other in the loop.
Good Tip, interesting thread.
Good Tip, interesting thread.
aerojunkie
Silver Member
I watched the video and if I understand it correctly couldn't the test be performed by simply unhooking the quick connect at the loader valve and moving the lever? Also disconnect the cylinders from either the bucket or the loader arms so they don't interfere with each other. I agree with RNeumann, just seems weird that the load cylinders outlast the curl cylinders.
SSdoxie
Elite Member
I suspect there is a partial restriction in QD connected to the base end of the curl cylinders. A partial restriction here will slow down oil flow out of the cylinder thus creating extra pressure in base that rod end has to overcome. As example; If working pressure is 2200 psi but the return QD is creating 200 psi back pressure then working force pressure in the cylinder at rod end is only 2000 psi. If you can Tee into the base end line take a reading there while curling and subtract that from the 2200 psi relief pressure.
aerojunkie
Silver Member
I may have found something that will be of help, if its already been stated I havent seen it. I was looking around about the loader on a kubota 3901 and saw this video. At 3:40 they discuss a series and parallel loader valve and the difference in how they operate.
Kubota L39 1 Tractor Advantage Video - YouTube
I believe the 2538 has a series valve just like the new holland in the video does, the loader seems to work the same when combining lift and curl functions. A new loader valve may be the only option but I have a thought on trying something but wanted to ask about possible problems. What if the hydraulic in and out hoses were switched on the loader valve? Then instead of lift getting the hydraulic flow first, maybe the curl function would?
Kubota L39 1 Tractor Advantage Video - YouTube
I believe the 2538 has a series valve just like the new holland in the video does, the loader seems to work the same when combining lift and curl functions. A new loader valve may be the only option but I have a thought on trying something but wanted to ask about possible problems. What if the hydraulic in and out hoses were switched on the loader valve? Then instead of lift getting the hydraulic flow first, maybe the curl function would?