Seen this ad on KIJIJI . How does this work ....a single hydraulic line to tractor

[rasorbackq]

Heavy duty farm dump trailer. Single axle. Single hydraulic line to connect to tractor. Removable rear gate. Metal bottom. Recent tires. Asking $1300 firm.

How does this work?? I thought hydraulics work with a forward and a return line?

 

[k0ua]

Heavy duty farm dump trailer. Single axle. Single hydraulic line to connect to tractor. Removable rear gate. Metal bottom. Recent tires. Asking $1300 firm.

How does this work?? I thought hydraulics work with a forward and a return line?

On a dump trailer you can use a single line because the weight of the trailer will push the fluid back down the line when you throw the control valve the other direction to lower the bed. Remember on your control valve you will have a neutral position than an A and B direction. When you push the control valve in the A direction it will direct the fluid flow to the A port. And lets say this is the port that your single hydraulic line is attached. Now fluid flow will flow out of the A port on the back of your tractor and extend the hydraulic cylinder, thus raising the bed on the trailer. If you return the control valve to the neutral position the bed will stay in the raised position. Now you move the valve to the B direction, The flow path of the fluid "deadheads" into the B port, which is not particularly a great thing but it is only for a few seconds, and the A port is now open to the Tank and the weight of the bed on the trailer will allow the fluid in the dump bed cylinder to flow back to the tank as the bed comes down.

 

[Avondale]

I am not sure without seeing a picture of the hyd ram but on my old haybine, the lift cyl only used one line, lowered by gravity and second ram port was "vented" to atmosphere, (i.e. wasted). It was a small ram, though.

 

[J_J]

Works just like KOua said.

However, if you don't want to hear the relief valve squeal. just run the B port on your valve to tank.