Increasing the lift capacity of a FEL

[mike69440]

Upsized Hydraulic Clyinders for Loaders

Re: Upsized Hydraulic Clyinders for Loaders, Started my L39 2000 Hr Hyd. Overhaul This was the motivating factor. http://www.tractorbynet.com/forums/kubota-owning-operating/359348-l39-tlb-bh1000-control-valve.html?highlight= I disassembled the control valve to see if there was a valve problem...

www.tractorbynet.com

I have ballasted my tractor to over 8,000 lbs in order to lift about 2600-2700 Lbs at center bucket. I estimate that lift is over 3,000 lbs at pins, must be a world record for an L series tractor. That weight is hard on front axle, as I broke the casting once.

 

[MossRoad]

We had a late 70's IH2500b tractor loader. It was basically a front end loader with a 3pt hitch. Someone put larger lift cylinders on it long before we bought it. There was no problems lifting the rear off the ground if you hooked a tree root or something. The side seams of the bucket cracked, I'm sure from the years of overlifting. It ended up breaking a spindle casting on the front.

I didn't have much into it. I got my money back out of it. But I'd say be happy with what your machine will lift, make sure the reliefs are set to factory specs, or buy a larger machine.

Good luck in your project.

 

[LD1]

Did you ever get the pressure tested? Pretty sure they are indeed 60mm cylinders. Every 100psi is gonna be ~200 pounds at the pins. So if its a few hundred psi low...could be easily robbing you of 400-500# actual lift capacity.

Larger cylinders are just more work than they are worth. Honestly....just setting pressure to spec is all I would do. I have been on several loader tractors....from Deere, kubota, yanmar, mahindra, etc. And kubota's just seem to be the smoothest to operate and feather control of both curl and dump. Id hate to screw that up if you use the loader alot for spreading and grading. Larger lift cylinders may react differently when trying to feather lift and curl for certain tasks.

After doing a pressure test....if you just deadhead a port on the loader valve (quick coupler with a gage and remove one of the hoses) if that dont reveal....its possible to have some worn cylinders. Especially since you said one appears replaced. Maybe try and "tee" the gauge in with the lift circuit. Ang get the loader to stall....like chained to a stump or something you know it wont lift. See what the "active" pressure is with the cylinders in the loop. If a cylinder is bypassing....the pressure will show significantly lower than static deadhead

Make sure your cylinders are correctly oriented....

Not sure what that has to do with anything at all?

 

[4570Man]

Make sure your cylinders are correctly oriented....

I seriously doubt the hoses would allow flipping them. But it would make zero difference if they were flipped.

 

[ning]

op, you say with forks - but I've seen light forks (~400#) and I've seen heavier forks by a couple hundred pounds.

You have to count the weight of the bucket or forks with the load they're carrying.

It's quite possible that you're wrong about the empty weight of the unit:

the specs of a unit sold today may not be the same as your lightly used units.

You also have to consider that your weight isn't 24" from the pins -- the pins are behind the forks and your load is mostly beyond 24", so that increases the effective weight.

I suspect in toto you're already above the rated capacity for the load location.

 

[jigs_n_fixtures]

I seriously doubt the hoses would allow flipping them. But it would make zero difference if they were flipped.

The rod side of the piston generates less force for the same pressure, due to the rod taking up some of the piston surface area. So, flipping end to end would make a substantial difference in lift capacity. That is why you don't see cylinders attached with the cylinder end at the bucket.

 

[bcp]

The cylinder must extend to lift. It extends by pressurizing the non-rod end. It doesn't matter if the non-rod end is up or down.

And there are loaders with the lift cylinder rod end toward the bucket and loaders with it toward the cab.

You don't often see bucket cylinders with the rod end toward the cab, as that would expose hoses and seals to more damage.

Bruce

 

[mike69440]

Did you ever get the pressure tested? Pretty sure they are indeed 60mm cylinders. Every 100psi is gonna be ~200 pounds at the pins. So if its a few hundred psi low...could be easily robbing you of 400-500# actual lift capacity.

Larger cylinders are just more work than they are worth. Honestly....just setting pressure to spec is all I would do. I have been on several loader tractors....from Deere, kubota, yanmar, mahindra, etc. And kubota's just seem to be the smoothest to operate and feather control of both curl and dump. Id hate to screw that up if you use the loader alot for spreading and grading. Larger lift cylinders may react differently when trying to feather lift and curl for certain tasks.

After doing a pressure test....if you just deadhead a port on the loader valve (quick coupler with a gage and remove one of the hoses) if that dont reveal....its possible to have some worn cylinders. Especially since you said one appears replaced. Maybe try and "tee" the gauge in with the lift circuit. Ang get the loader to stall....like chained to a stump or something you know it wont lift. See what the "active" pressure is with the cylinders in the loop. If a cylinder is bypassing....the pressure will show significantly lower than static deadhead


Not sure what that has to do with anything at all?

L39, L45, L47 lift cylinders are 55mm, bucket cylinders are 60mm. I upsized both 5mm.
Unknowingly I was running my pressures @ +3,300 psig before I got around to putting a gage on the system. I kept turning up the relief without checking! Shame on me.
So by upping the cylinders a bit, I am running 3,000 psig to be kind to hydraulic pump, valves an hoses. Also have a cushion accumulator.
With an additional 1,000 plus of ballast, the machine is over 8,000 lbs. Wheel spacers widen rear track 2" for winter chains and add a bit of stability.
Fuel is turned up to provide low 40's hp, to counter the extra weight.
As a old mechanical eng8neer and hot rudder. I think I have learned the hard way finding how enough is enough.
The L39 overall capability is very balanced and is at its practical limit.
It is very reliable, & amazing for it's size.
Operating other ag. tractors is very disappointing and seems difficult, as they feel so gutless.

 

[4570Man]

The rod side of the piston generates less force for the same pressure, due to the rod taking up some of the piston surface area. So, flipping end to end would make a substantial difference in lift capacity. That is why you don't see cylinders attached with the cylinder end at the bucket.

I’m aware of that but the cylinder is using the stronger extension mode to lift the loader regardless of which way it’s mounted. The bucket curl cylinders on the vast majority of machines are using the cylinders in the weaker retraction mode to curl the bucket up. Some larger loaders use a lever on the curl function so the cylinders can extend while curling up.

 

[MossRoad]

The rod side of the piston generates less force for the same pressure, due to the rod taking up some of the piston surface area. So, flipping end to end would make a substantial difference in lift capacity. That is why you don't see cylinders attached with the cylinder end at the bucket.

It wouldn't make any difference in lifting power at all.
Think about it.
When the cylinder extends, the large end of the piston is pushing no matter the orientation of the cylinder. It doesn't care if it's pushing against the frame of the loader or the loader arm. Pushing is pushing.