BIGGER loader cylinders.

[Reg]

OK, so if ANYONE ELSE asked about this I would just say "DON'T"

That said, I am running out of lift capacity on my C50-HL.
Supposedly it has 2540 lbs capacity and given that I just had a 40 cu ft trunk of sappy sappy pine on it (plus the grapple) I think it is working as designed and built.

But, there is always a BUTT.
That barely got off the ground and I wouldn't have been able to load it onto a trailer, I put it down and cut it before dumping.

According to the manual it has 55mm internal bore cylinders (the C50 has 50mm cylinders).
So, hydraulics being what it is - a 10% increase in diameter should offer a 21% increase in available force (at the cylinder, ignoring loader geometry for the moment).
I am thinking 60mm might give me what I want, it comes out to ~19%.
65mm would give ~39.7% and I think other things could fall victim to what I might then be tempted to lift (&carry).
There may be some inch sizes that would work, but I think I want to AVOID going over 25% increase.

Basic question; Has anyone here actually DONE an up-size on this loader ?
If so, how did it work out ?

I am well aware that there may be other limitations, e.g. stresses on other parts, stability when lifting (and CARRYING) larger loads than designed for.
With the pine trunk in the grapple I had the hoe on the back at the time and my R4s are loaded with RimGuard - so it wasn't about to do a front wheel stand (a "stoppie").

BTW, Surplus center cylinders in this sort of size seem to be $250 - $280, so it is likely a $500 < project.

 

[oldpilgrim]

bigger cyls mean slower operation. Are you ready to slow down everyday operations for the few times you actually need the lift?

I'd be worried about the front end under a 25% load increase.

 

[oldnslo]

If you Change the lift cylinder sizes to obtain more lift will the curl cylinders handle the extra load or will they now be the next "weak" link.

 

[BHD]

if one can get closer to the tractor it should lift it easier, depending on what you had for an attachment the further from the pivot point the more weight it appears, to the tractor, less mechanical advantage,

chain off the front of the loader, not the bucket, if forks are on a bucket, use forks with out a bucket, just the few inches the bucket is deep can make one lose a lot of lift capacity, (check psi on tractor and see if the tractor is developing the correct pressure for the hydraulics,

bigger cylinder, my mean broken front axle, bent loader arms, and a whole bunch of other expensive and fun problems,

you most likely did the best cut the tree smaller,

 

[Midniteoyl]

If your pump can handle it, you could also adjust your psi up 100-150.

 

[Reg]

Slower lift COULD be a plus, especially with heavy loads.
Fast and jerky vs slow and smooth.

Bucket cylinders seem to have better mechanical advantage than lift cylinders do anyway, as witnessed by the breakout force being about 900 lbs greater than the lift force.
Closer in ? Well, sure but I am using a grapple and while it is true that it can lift a little more in the vertical "grab it" position I don't like to raise it very far before rolling back into a carrying position - and rolling back does extend the load away from the pivot.

Not saying I haven't lifted, then rolled back, but it never feels right to rely solely on the grapple's grip.
I could and SHOULD clear the site a bit more before taking out a ton or so; saws, fuel cans. etc. - - but if you drop something that big it will always roll to where it can do the most injury/damage anyway

I agree with the whole "upgrade this and you will likely break that" argument, but Kukje tractors and Humpolec loaders are tough and I am confident that there is AT LEAST another 30% capacity in the "everything else".
Again, 20% to 25% should keep me (or any future owners) within what the tractor can take.

 

[Luke'sScreenName]

Have you already increased your relief pressure above spec?

 

[Reg]

Have you already increased your relief pressure above spec?

I have not.
I have taken that it can lift a ton of wood plus the grapple as fair evidence that it is at least up to spec.

I would rather go for cylinders with say 19 % more cross sectional area than put an equivalent 19% more pressure through the whole hydraulics system - although as I say that I realize that there is probably more margin in all the hoses and valves than in a lot of the mechanical bits

Anyway, I was looking more for someone who has actually DONE a cylinder up size and their results.

 

[Reg]

Having "slept on it" I think I will try turning up the relief pressure.
a) I don't have a suitable pressure gauge, but buying one is a good idea anyway for trouble shooting and they MUST be cheaper than bigger cylinders.
b) This is reversible.
c) A little more BITE in the grapple would be reassuring.
d) A little more FORCE would be nice ...well, just about EVERYWHERE

 

[LD1]

I think you have a good plan for step 1 in getting a gauge.

But a couple of notes.

1st, about you assuming the curl is stronger based on higher breakout force. It has been discussed (and even argued about) before on TBN, but breakout force is not curl power. Rather it is your lift power, but at ground level.

If you are familiar with hydraulics, you know that the cylinders angle changes the force it can lift with. Well, a loader travels in an arc as it raises, thus changing the cylinder angle. The result is the higher you lift something, the lower the capacity. Or in other words, the lower you the height, the more power you have. Thus the 900# difference between breakout (ground level lift) and lift to max height.

Second note, Increasing cylinder bore area by 19% will increase your lifting capacity by a good bit more than 19%. How much more all depends on the geometry of the loader and cylinders and I have no idea what they are for your loader, But here is a rough example:

Lets say you are operating at 2500psi and that gets you 2500# of lift capacity. Well, the loader frame + bucket or grapple arent lifted for free. That takes power just the same as a load in the grapple would. (again, how much so depends on the geometry). So you have to figure the true lifting force the cylinders can generate on their given angle, and given distance (leverage) from lift and pivot points......THEN subtract the dead weight of the loader and you arrive at your 2500# lift spec. Increasing cylinder bore area by 19% increases their lifting power by 19%, but the dead weight of the loader frame/bucket remains the same. So the net result is more than 19% increase in bucket capacity.

Hope you can follow that. Here is a simplistic example.:
current cylinders can push on the loader frame with an upward force of 3500#. But it takes 1000# to lift it empty. Result is 2500# avaliable for lifting a load.

Increase cylinder power by 19%.....3500 x 1.19 = 4165#. Now take off the same 1000# required to lift the frame/bucket and the new lifting capacity is 3165#. Which is a 26.6% increase in bucket capacity with a simple 19% cylinder size increase.


Now along those same lines, increasing pressure has the same result. Since the dead weight stays the same. If you increase pressure by 19%, you are increasing real lift capacity by a fair bit more than that.

With your loader rated at 2500#, and probably a 2500psi spec, one would tend to think it is simple in that for each PSI you increase, you can lift an additional pound. But remember, the weight of the loader. With that 2500PSI you are really lifting something probably around 3500# with that dead weight. So, 3500/2500 is more like 1.4# for every PSI increase. So a 200psi bump in pressure is probably gonna net closer to 300# of extra lift capacity as opposed to 200#

 

[Reg]

Yes, clearly the overhead of lifting the loader's arms is already in the base case and any percentage increase in force at the cylinder returns a greater percentage increase in PAYLOAD.

Not as much as one might think, since although the loader (with 67 inch bucket) has a spec weight of 1320 lbs very little of that is actually lifted.
MOST of the loader's weight is in the frame, not the arms.

PART of the reason that I bought a narrow grapple was to save overhead weight, i.e. every additional pound of grapple weight is a pound less of payload.

For brush a wide grapple is probably better, it can grab more and the load is less dense, for logs it is important to center the load as much as possible anyway and that is as easy with a narrow grapple as with a wide one - plus the benefit of the higher payload.

 

[LD1]

Actually, it takes more than you would think to lift just the empty loader. Them buckets are heavy, and dangling way out in front of the cylinders so they have alot of leverage.

On both my old L3400 and my new mx5100, it takes about 600 psi just to lift it empty.

So thinking in terms of 2400psi spec for operating pressure, it takes 25% just to lift empty. Or in other words, you only have about 75% of the cylinders power to be used for lifting whatever you put in the bucket.

 

[Reg]

The end run around figuring all the geometry would be to put a pressure gauge in a lift cylinder and read it when it just gets off the ground - I guess that would also be the pressure to hold it too.
Hmmm, that may be a good way to actually WEIGH logs - - ...probably not.

In real world terms I'll just turn up the relief pressure and (subjectively) see how much bigger tree trunks I can lift.
If that doesn't impress me (again, a subjective measure) I'll start spec'ing out fatter cylinders

None of this before I get a gauge to at least measure the current relief pressure.
I want to be able to reverse this with some accuracy, just in case some other problem crops up.
"Set to spec" can be a useful troubleshooting technique.

 

[LincTex]

I'd be worried about the hydraulic pump & drive gears.

Two Examples:
1) The Farmall M, Super M must use the distributor gear from a 400/450 when going with a "live" pump (goes between distributor and accssy case). The hydraulic pump adds that much load.

2) My 1980 John Deere 850 (Yanmar) sheared a pump shaft key, doing loader work. It spalled the shaft pretty bad. When I had the pump off to change the key, I noticed the steel gears were carving a "new" travel path into the aluminum housing.... VERY bad.

I'm Jus' Sayin' - - be cautious!!!
No one ever "gains" anything for free.

 

[art]

I don't get into this to often but have you looked at the load capacity of the front end? You might want to look at that first although a little bump on pressure might be all you can handle. I have seen tractors with to big of loaders and lifting to full capacity breaking the front axles.

 

[Turbys_1700]

Most all manufacturers set the relief a little below the max. I would adjust the relief first as many here have suggested. I would also as art suggest double check the capacity of your front axle. Factory specifications typically allow users to maximize pressure and still stay under their front axle capacity if using factory loaders. Ensure that any modifications to increase lift capacity were within the specifications of the front axle to carry the load.

 

[SPYDERLK]

Actually, it takes more than you would think to lift just the empty loader. Them buckets are heavy, and dangling way out in front of the cylinders so they have alot of leverage.

On both my old L3400 and my new mx5100, it takes about 600 psi just to lift it empty.

So thinking in terms of 2400psi spec for operating pressure, it takes 25% just to lift empty. Or in other words, you only have about 75% of the cylinders power to be used for lifting whatever you put in the bucket.

Other real life corroborating data:

I have had the opportunity to do measurements at points on a boompole using a Dillon force gage. I used the 7520 as the test platform and turned hyd pressure down to 1000PSI so I wouldnt bend the boompole. I did 2 setups:
1]

Used a chain in place of the toplink to get the lift ratio as close to 1 as possible. Best I could do was 3/4 - - 24" lift at the eyes and 32" at the end loop of pole 108" out from the eyes.​

2]

Used the toplink adjusted to max length. The best lift ratio I could get at the pole end was 0.61​

The lift forces I measured in the 1st case were 1710# at the eyes, 1160 @ 56", and 980 @ 108".

The lift forces in the second case were 1700, 1200, 880 respectively.

,,,I believe the anomalies shown are due to my neglect in assuring that the lift was always done at the same eye height. The force available at the eyes varies some with height.

I did one more experiment in case 2 by successively shortening the toplink 3 turns at a time. Here I did take care to hold eye height pretty close to constant. The force measurements at 108"were 880, 850, 800, 760, 725.

While I had the force gage I took some loader measurements too. I found that it took 700PSI to get the loader to rise with the Tilt-tatch and bucket -- and 800PSI to get it to full height. I then turned the pressure up to 3000 as I normally keep it set. Center bucket force was 5100# at 1 foot lift height. ... Quite a surprise since this is 26" forward of the pins.​

 

[Sawyer Rob]

I say "do it", I'm betting your dealer has some front end parts he'd like to sell you! lol

SR

 

[EddieWalker]

I learned my lesson years ago with trying to out think the engineers who design vehicles and machinery. They do it for a living. They do all the research and factor in all the component. Sometimes the get it wrong, but overall, they know a lot more then I ever will. If it was just a matter of putting on bigger cylinders, that would be pretty simple for them to do at the factory. Then they would sell more units because of the greater lift ability compared to the competition. My guess is that the loader came with the very largest cylinders that they calculated the tractor could handle when considering the pump, the pins, the metal used to build the loader arms, the frame of the tractor and the strength of the axle supporting the weight. It's the same when figuring out the size of the bucket. Just putting a bigger bucket on the loader does not mean your tractor can handle it.

If it's really such a concern as to consider rebuilding or home engineering modifications to it, in my opinion, you would be better off for the long term selling what you have a getting something bigger.