I used to be able to get the bed to go down by jerking/braking the truck at slow speeds. over the past year I have used the speed bump near my house to the same, but now it is more stubborn than a mule and has not gone down. The pump is a PTO. The cylinder is a single action. I have not tried to disconnect the hose from the PTO to lower the cylinder due to fear of air in the line. Where should I start?
Three possibilities, either the valve is not shifting correctly, the cylinder is mechanically stuck, or the liner of the hydraulic hose has come apart inside and has collapsed into a rubber plug...
Had one recently, five minutes with a grease gun on the hinge points and it worked like a charm. They couldn't believe it was that simple.
If I were to remove the hose, what precautions do I need to take with regards to air admittance?
Top and bottom, where the cylinder is mounted to the frame and dump bed? It is worth a try. On a side note, I filled it with enough (60% full) earth to get it to go down again.
Make sure the box is blocked up before doing anything with it. It can drop fast. Been many fatalities over theyears from boxes dropping on people.
Yes, there is a build in stand for just this, I have heard of people using 2x4s their last time. I was actually planning to work on it while it is in the down position, so I could do it indoors. Here is a pic of the truck, here is the bed just before it dropped back down this afternoon: