slow loader goes fast with cylinder unhooked.

jinman · Dec 7, 2008

funny farmer said:
So are we all agreeing that theres isn't anything wrong then? From what I understand thats just the way hydrolic systems work.

What you should see with one cylinder's pin disconnected and dumping the bucket is as follows:

1. As the bucket starts to move, the disconnected cylinder goes in the opposite direction of the connected one.

2. As the bucket swings down and the connected cylinder reaches maximum extension, the unattached cylinder begins to extend and also reaches maximum.

This is because the unattached cylinder is in parallel with the attached one. The weight of the bucket wants to pull the attached cylinder down, but the flow of hydraulic fluid from the pump is limited. Therefore, the attached cylinder sucks fluid out of the top of the unattached cylinder until it reaches maximum extension, when the pressure from the pump then sends fluid to the disconnected cylinder and pushes it out to its maximum extension. If both cylinders are extending together, then there is something really, really strange going on.

Watch your cylinders closely. I'd bet what I describe above is what is happening. Your slow normal operation is due to your tractor not having a lot of hydraulic flow to the FEL. Your pump probably only has 4 gpm maximum while newer tractors have 8-10 gpm or more.

Knight · Dec 7, 2008

Some loader control valves deal with slow dump speed by having a regenerative dump built into the curl spool valve. Instead of circulating oil through pump, oil is bypassing the tractor pump and just redirected back into the starving side of the cylinder and using the weight of the load to speed up the dump.
If you don't have this option built in, then you will have a slower dump speed and I would say that is normal.

funny farmer · Dec 8, 2008

I finally got the tractor started today,(had problems due to the cold) I took out that pin and operated the controls to see what was really happening. You guys were right, the left piston fills up with fluid first, and then the right one will extend out. It makes sense to me now with that scenario playing out; I thought it was the other way around which didn't make sense. I started feeding out round bales today with only the one cylinder hooked up, and the way the bucket was bouncing and putting that much more pressure on the one side, I made a decision to hook it back up. Guess I'll just deal with it being slow. Thanks for all your comments and advise, it wasn't a serious issue, just my curiosity.

kennyd · Dec 8, 2008

Does your tractor have a externally driven hydraulic pump? Like that's driven from a belt or shaft? If so, then you might be able to upgrade the pump to one with more flow.

J_J · Dec 8, 2008

I have three hydraulic pumps on my Power-Trac, and one of them is driven by the fan belt. I would think you would be able to hook up another hyd pump. with more capacity, and therefore give better response.

J_J · Dec 8, 2008

J_J said:
I have three hydraulic pumps on my Power-Trac, and one of them is driven by the fan belt. I would think you would be able to hook up another hyd pump. with more capacity, and therefore give better response.

Perhaps there is a way to combine the flow from two different pump, by using check valves and adding a tee fitting to combine flow and send it to the loader valve.