The Stovebolt Site Forums The Parking Lot Big Bolts Dump Body Problem - It's Stuck!

Yesterday I dumped a piece of granite out of my '51 4400 but the bed will not drop now. The way I remember this operates is with the truck in neutral, push in the clutch and pull the knob on the dash which engages the PTO. When you take your foot off the clutch, the bed will begin to rise and stop when it gets all the way up. To lower, there is a flat iron bar coming up through the floor in the cab that is pushed forward and the bed will drop. The lever in the cab floor depresses the "button" on the valve body and I guess allows the oil to drain from the cylinders into the reservoir. No amount of depressing the button with either the lever or with a pry bar will work. For some reason, the bed will not drop now and I'm fortunate that it is in my driveway and not down the road where I couldn't leave it. So how do I get this thing to come down? I suppose I could loosen hose fittings and let the oil "leak" out but it appears that something needs fixing so that I can use the dump function. Anybody familiar with this type of hydraulic system?

Also, when I try to view the added pictures they are all blue, until I hit the x to close them - the a full color version appears for a very brief moment and then it closes.

I don’t know the answer for you but whatever you do DO NOT place any part of your body under that bed without a safety prop in place while you are loosening fittings. They have a propensity to drop unexpectedly. BE SAFE

I don't like sticking my body in there in or under there in any case.

Funny thing these old trucks. I went out this morning and pushed the lever forward and it came right down. Although I don't remember it working this way in the past, I think the PTO needs to be disengaged to lower it.

All the similar dump bodies I've worked with had a 3 position arrangement on the bed lever- - - -raise/stop/lower. All the PTO does is run the pump. You should be able to engage the PTO drive with the bed lever in the center position without anything moving. Move the lever one way to raise, center it to stop at any position you choose, and push the lever the other direction to lower. It's worth a try that way.
Jerry

Gazz As others said don't get in it's way,if your not on level ground linkage can bind,or if load comes out uneven can bind. Be careful leaving it overnite if oil leaks out bed can fall and severely bend your frame, just take your time and study it you''ll figure it out. Most systems have a metering orifice so the bed can't come down too fast,sometimes when spreading you need to let it down some so you can start again in another place. A skilled spreader man NEVER scoops !! LOL

I'm not as familiar with the older systems, but it still sounds like the big lever controls a valve (3-way?) that either sends oil (Hyd fluid) to the cylinder to raise the bed, holds it in place, or opens the system to let the fluid flow back to the reservoir (and lower the body). Maybe that valve was sticking?

At any rate, the more experienced guys can correct me or validate me on this, but I've always been taught to disengage the PTO when done raising the bed - don't let the PTO pump against a closed valve (bad things happen).

Thanks for comments! As near as I can tell, once the pto is engaged, the bed will begin lifting. Pushing the lever on the floor forward pushes the release valve in - it's the part there by the cotter pin that looks like it is coming out. It seems it's on or off unlike the hydraulics on my newer Kubota. And I believe there is a flow restrictor of some kind to prevent the bed from dropping like a rock.

It sounds like you've got a lift valve malfunction of some sort. You should be able to raise the bed a little, and go to the "hold' position in the center of the lever's travel without disengaging the PTO. Of course, there are all sorts of lift systems out there, and I've by no means worked with all of them. It just doesn't make good nonsense to have an "all or nothing" situation when lifting the bed. Hydraulic pumps have a relief valve built in to prevent damage when running against a closed valve, but it's not a good idea to do that for long. All the drivers I worked with at a big sand, gravel, and concrete outfit in California knew to disengage the PTO before getting back onto the road if they wanted to stay employed!
Jerry

If you look at the first picture, you can see the end of the floor lever linkage where it pushes against the "button" of the valve. The tee at the other end distributes the oil to each of the two cylinders. Without me messing around with it a bit more I believe the lever either pushes the button or doesn't. There is no way to "feel" where the lever is during operation as that button moves maybe only an inch or so. I agree that there should be some way to control how high you want the bed to go and maybe that is the clutch.

Gazz,

The valve body on the ram mechanism should have the following positions: lift, hold, lower. It sounds like you are having some issues with either the valve body itself (there are often detent balls on a shaft rail that positively "lock" into each of the 3 positions (much like on the transmission shift rails). Crud or rust may be causing difficulty in actuating the valve body to the "lower" position. It also could be your shifter linkage. On my dumper, there is a quite long metal rod that attaches from the lever in the cab all the way to the valve body on the ram cylinder. This rod has many bends and curves and could possibly be bent making it unable to move the valve body into all of its positions. The rod I mentioned should have a threaded clevis joint for adjustment. Your ram system is much more modern than mine, but they all seem to work on the same basic principle.

You will figure it out!

Paul

That system looks like one Fred Flintstone might have used! With a little creative plumbing you could probably retro-fit it for a more conventional 3-position valve that recycles the fluid back into the reservoir when it's in the center position, like the control valves on a log splitter or another hydraulic powered device.

Gazz Your right about the clutch on bed hight but if you clutch it you stop then you have a pile to scoop. When I spread I raise the bed till rocks start falling (can see them below the bed deck) then throw it in dual low let the clutch out and spread hopefully till it's all out. If you must stop,let the bed down at least some go start in another place. My tail gate has 2 4x12 inch holes so graval goes in just the tracks on the driveway or can cover those holes and go full width . Can set tail gate opening for any rate then.