Country dump trailer + hydraulic pump?? -long

lhfarm · May 22, 2007

I made the road trip to Fredericktown, OH (about a 10 hour round trip) to pick up a 2 ton dump trailer from Country Manufacturing. Beautiful drive and the wagon was assembled and waiting for me when I arrived. I've read enough here to know exactly what to expect - a nice trailer for the price.

I hauled the trailer home in my 5x10 utility trailer without any problems. I stopped on my way home and purchased a 24"x4" cylinder from the local Rural King store, along with hoses and a control valve (two-way like used on a spliter (all they had)) for an old 12v pump I had on hand.

Since they had assembled the trailer for me, I thought I would get started right away. Getting the cylinder mounted was much tougher than I expected. The fit is perfect, but I think it is really a two person job. Not having an extra set of hands, I used the FEL and a chain to raise the trailer bed high even to give me some working clearance. That worked great for the case end. Attaching the the ram end was harder, in part because I didn't have fine enough control to extend the cylinder (more on this later). I finally used a farm jack to raise the bed slightly and by playing with extending and retracting the rod got the second pin in.

The plan is to load the trailer with my backhoe (the TC40DA is parked in the background) and use my jeep or Cub Lo-Boy to tow the trailer. So I need a self-contained hydraulic unit. As stated above, I had a pump + reservior that I had purchased for another jeep project. As can be seen in the picture, the pump will lift the bed, but I can't seem to fully extend the cylinder.

I don't know much about the pump - an e-bay purchased and I don't know much about hydraulic systems either. Before I mounted the cylinder, I tried to fill the cylinder and hoses with hydraulic fluid (I used the NH fluid, since I will be using the TC40DA to pull the wagon sometimes). I had to fill the reservior a few times before the ram would move.

First question - how do I know when the system it full - should the reservior be filled to the top when the cylinder is fully retracted?

Second question - Since this is a closed system, how do I bleed the air out? Loosen a connection? There is a 1/4 inch plug in the reservior tank. Is that for bleeding the system?

Third question - Why isn't the cylinder fully extending? Is the tank large enough for this cylinder? Pump too small?

The setup does work, but I am going to be loading very heavy cattails that I am digging out of my ponds. What would should I try next?

hazmat · May 22, 2007

What is the volume of the tank? I'd say you need a bigger reservoir. The reservoir should be vented to atmosphere somehow - the trapped air needs to escape.

Does it work if you hook it up to the TC40DA?

As you may remember - I have the same trailer. When I set it up, I cycled it up & down a few times & then reset the fluid level in the tractor with the cylinder retracted - took a bit those hoses can store a bit of fluid...

lhfarm · May 22, 2007

hazmat said:
What is the volume of the tank? I'd say you need a bigger reservoir. The reservoir should be vented to atmosphere somehow - the trapped air needs to escape.

Does it work if you hook it up to the TC40DA?

As you may remember - I have the same trailer. When I set it up, I cycled it up & down a few times & then reset the fluid level in the tractor with the cylinder retracted - took a bit those hoses can store a bit of fluid...

I used your experiences as a guide for buying the hoses and remembered your remarks about wishing you could have put the cylinder in place while you where assemblying the trailer.
I will vent the reservior the next time I'm at the farm and see if that helps. I'll also take the BH off and give it a try with the tractor remotes.

I hope to be able to put a box on the trailer to hold the pump, battery and control, so I can pull it with whatever is handy.

Thanks for the suggestions.

firefighter9208 · May 22, 2007

There should be a bleed screw on the top of the hydraulic cylinder. You should be able to loosen it with your fingers. Engage the pump and let the cylinder extend as far as it will, loosen the screw until fluid starts coming out.

How do I know? I just bought a dump truck and had to repair a leak on a hydraulic line going to one of the cylinders. I couldn't get the bed to fully dump when finished. I had a buddy stop by that walked up loosened the bleed screws, the air came out, he tightened the screws and the bed extended. I was like duh?

Chris

lhfarm · May 25, 2007

OK, removed the 1/4" plug on the reservior and started the pump. It lifted the bed all the way. When I went to lower the bed, the fluid filled the reservior and started overflowing. I stuck a hose in plug hole and removed about a quart of foamy fluild.
Raised and lowered the bed a couple of time. It goes up - not smoothly, but pretty quickly. When lowering, it wants to push fluid out of the tank. I put the plug back in, lowered the bed, then released the air pressure in the system by slowly unscrewing the plug.
So - Do I need a bigger reservior? Could I rig a small overflow tank? Do I just need a vented tank? What would you try next?

Thanks

RonMar · May 25, 2007

It is hard to tell in the picture, but it appears that you have the pump and resovoir assembly attached to a single spool valve(looks like a open center logsplitter valve). Is this correct? If so I am assuming you raise the bed by turning on the pump and then working the lever? Let me also guess that you are just lowering the bed by lowering the lever without the pump on?

Try lowering it with the pump running. What I think is happening is as you raise the bed, the pump will draw from the resovoir and lift the bed by filling the bottom of the cylinder via the working port on the spool valve. As the ram extends, fluid on top of the piston will be forced back thru the upper hose to the spool valve return port and into the resovoir. basically transfering the fluid from the top of the ram to the bottom of the ram via the resovoir and pump. When you lower the bed without the pump, the fluid is forced by gravity weight on the bed compressing the cylinder and flows back to the resovoir via the spool valve return port, but there is no supply fluid feeding the spool valve port going to the top of the cylinder. It is probably sucking air from somewhere(maybe back thru the spool valve safety from the resovoir return line) to feed the suction created on the top or rod end of the cylinder as it compresses. At any rate, since fluid is not going to the top of the cylinder, the fluid returning from the bottom of the cylinder quickly overfills the resovoir. You can sometimes do the same thing with a tractor by lowering the loader with the engine shut off.

Now with the plug back in the resovoir, it may build enough pressure to force fluid back to the top of the cylinder, but you want to make sure that the return line to the resovoir as well as the suction line are well below the fluid level in the resovoir so they can't suck air. The purpose of the resovoir is to trap air that makes it into the system and you don't want that air to be forced back into a cylinder.

If it is a sealed resovoir(unvented) as it sounds like it is, What I would try is with the plug removed, cycle the bed full up and down several times with the pump running to purge as much air as possible from the system. Keep topping off the resovoir as air works out of cylinder and hoses. Once this is done, top off the resovoir and re-install the plug and see what happens when lowering with the pump shutoff. If you find the bed loosing it's ability to fully raise, then you are sucking in air someplace as it is far easier to draw air in than to suck fluid along a pipe. If this happens, you will probably have to always use the pump to lower the bed. You might also experience difficulty breaking and making the quick connect fittings in a closed/sealed system. Broken in cool temp, go to remake at a higher temp and the thermal expansion of the fluid in the system makes it impossible to get the checkballs in the QC's to open and seat fully. Gotta open a vent or loosen a fitting to relieve the pressure to allow the QC's to seat.

schmism · May 25, 2007

so i know its mostly a hydraulic question but

why did you choose the trailer vs the waggon?

im trying to figure out which i want and for the life of me cant figure out why i would want a trailer version over a waggon version.

lhfarm · May 26, 2007

Ron,
Thanks for the great explanation. I'll give it a try today. You are correct about the valve type. I did try lowering the bed with the pump on and off, but it was random. I'll go through the steps. Is there a reason not to vent the system by replacing the plug with a screened tube?

Thanks,

lhfarm · May 26, 2007

schmism said:
so i know its mostly a hydraulic question but

why did you choose the trailer vs the waggon?

im trying to figure out which i want and for the life of me cant figure out why i would want a trailer version over a waggon version.

I hate backing wagons. I've had lots of practice backing hay wagons into my old barn. I can do it, but I don't like having to think that much. I have lots of woods and I want to be able to move the trailer in and out of tight spots.

The drop down jack makes it pretty simple to unhitch the trailer, load with the FEL and rehitch - at least that is what I'm assuming, since I haven't hooked it to the tractor yet.

jeffinsgf · May 26, 2007

schmism said:
so i know its mostly a hydraulic question but

why did you choose the trailer vs the waggon?

im trying to figure out which i want and for the life of me cant figure out why i would want a trailer version over a waggon version.

I have the wagon. If I had it to do over, I would get the trailer and a good jack with a caster (high quality boat trailer jack). Backing the wagon is an exercise in anger management.