Hydraulic Lines: Fear of Failure

[Short Game]

The tractor went over the 50 hour mark this evening as I split a trailer load of wood. I got it five weeks ago, yesterday. Everything is brand new and the first negative thing I noticed about it was that lack of curling power with the bucket. I had to move two 12'6" cherry logs for a neighbor. They were about 11 and 13 inches in diameter. I know I could have lifted both together with my smaller Cub Cadet. No way could the new tractor pick them both up.

I only get to town once in two weeks, so I won't get any gage setup until a week from Tuesday or Wednesday. I'm going to split another trailer of wood tomorrow and switch back to mowing for a few days. I'll be hitting the LS dealer for a couple of things. I'm miles behind schedule because of not having a tractor since mid winter. Much of the time since I got the new tractor has been taken up with getting it set up to do my wood chores like my old one was. That was between not letting my 40 miles of 72 inch wide mowing get completely away from me. Most years I mow every week. This year I have been letting it go two weeks or more.

The loader looks pretty stout, like it should easily handle what I'd throw at it.

LL4100 loader

 

[Egon]

On the loader curl; check out the quick connects, the line connecting diagram and the joy stick mechanicals for proper set up.

 

[Short Game]

On the loader curl; check out the quick connects, the line connecting diagram and the joy stick mechanicals for proper set up.

Looking through the LL4100 FEL manual, I see that the technical term in use here is "bucket rollback." With all the connections being color coded, it's hard to imagine the lineup of this new loader could be wrong. I can't imagine a wrong lineup that would only render it simply weaker. The specs do have times for bucket dump and bucket rollback. I can time them and get an idea of whether the weak rollback is how they designed it. Of course, I don't know what engine RPM those times are for. But, at a constant RPM, the ratio would tell the tale.

What I notice in design differences between my old Cub and this LS are these: with the quick-release mechanisms and structure between the pivot pins and the bucket, the mechanical advantage is less, as the load is farther out from the pivot pins. Another thing is, on this bucket, the upper and lower pins are closer together than my old one, and seem to be closer together than any other brand of tractor bucket I can find in pictures around this site.

I just went out and measured both loaders.

The LS's LL4100 loader is 33 inches from blade edge to pivot pin. The upper and lower pins are spaced 5 3/4 inches, on center. The bucket cylinders are 2 1/2" X 19 1/2" O.D.

The Cub Cadet's 417 loader is 23 inches from blade edge to pivot pin. The upper and lower pins are spaced 8 3/4 inches, on center. The bucket cylinders are 2 1/2" X 21 1/2" O.D.

Based on the geometry alone, I think I can see why the Cub's rollback is so much stronger. The only variable left that I can think of are the operating pressures.

LS 4010/20: 2422 psi.*

Cub Cadet 727*: 2133 psi.*

* Book, not actual measured.

If you ask me, it looks like it's designed to be weak on rollback. I think they're saving money on the bucket cylinders. I'd sacrifice a little time for some power. I'd also probably give up a little dump angle, but a longer cylinder and more reach between the pins would fix that.

 

[Egon]

It was worth a though anyway.

 

[Short Game]

It was worth a though anyway.

I really appreciate your thinking about this for me. It definitely got me in gear. Thanks.

 

[J_J]

The cyl are more than capable of doing the job.

It is not the pressure that would slow down the cyl. The fluid volume is what determines the speed of operation, and lever manipulation, or restrictors in line.

Pressure and size of the cyl determines the force applied.

Rollback speed is a function of cyl size, volume, and rod length, and mechanical placement of the pins. A shorter separation will give a faster speed. a longer separation between the pins will give a better mechanical advantage, and sklower time.

If you really need more power, then increase cyl size, or boost up the relief pressure.

 

[Short Game]

I think my best solution for my log forking issue will be to take advantage of my quick-release bucket and build a quick-release forks/boom pole combo base. It will get rid of that huge 33 inch lever arm to the base of my bucket forks, bringing the lever arm to around eleven inches, tripling the maximum fork rollback leverage. It will get the bucket out of the way for using the boom pole, though the gain in leverage for that device will be not so great as in the case of the forks. It will still be a good deal more and it's reach will be more in the clear.

I will make the forks a full six feet wide for logs. I can set it up to be narrower, should I want that option at any time.

Just what I needed, another project. :confused2:

 

[2458n]

Why have you not gone back to the dealer on this? The front end loader was not made to operate in such a poor way. If the system was factory made it would be able to do way more then the older smaller Cub. Get on the phone and let them know something is not right! You paid good money and expect a product that works the way it should. You should not have to redesign anything- what you are doing is well within the normal requirements.

 

[J_J]

Can you show pictures of the geometry of the loader pins and cyl arrangement on both tractors?

 

[Short Game]

Rollback speed is a function of cyl size, volume, and rod length, and mechanical placement of the pins. A shorter separation will give a faster speed. a longer separation between the pins will give a better mechanical advantage, and slower time.

If you really need more power, then increase cyl size, or boost up the relief pressure.

I think I have most of that figured. I would be hesitant to change the pin separation with my tools and shop situation. Spreading the pins would necessitate a longer travel, so, new cylinders anyway. Bigger cylinders will be what I'll do if this issue seriously affects digging. I will be checking that pressure (suspect) when I get set up to do it.

As for now, I've convinced myself to build the fork setup that would best serve my purposes.

J_J, you seem to be the guy for hydraulic questions, but I do not as yet know the lingo. I've been more of an operator than a tech so far in this incarnation. I always like to learn new stuff, so thanks.