Adding a dumpbed to 3/4 ton chevy

[Adamc44]

I have a 85 3/4 ton Chevy 4x4 w/ 4speed. The bed is rusted out so I'm going to drop a flatbed on her. Thought it would be cool to add a dump to it. She'll be mainly used for hauling firewood and maybe some gravel or dirt. I'm needing help on what I will need for the best setup so as to not waste money cause I'm a hydraulic rookie. What setup have you guys seen? I thought maybe a 12 volt pump, get a used hydraulic tank off Craigslist then find a dump cylinder n appropriate valves. I want it to power up n down. What size and type of pump, valves, cylinder would I need to make this work? If you guys have any better ideas I'd appreciate hearing them. I want to keep this somewhat affordable as well. Any help, guidance, criticism, or suggestions is welcome
Thanks
Adam

 

[LD1]

I did this a few years ago to an old dodge W350.

First, you cant just use any old flatbed unless you beef it up. Most arent built heavy enough to be a dump and are designed to "sit" on the truck frame and use its strength.

The cylinder size will depend on ALOT of things"
1. cylinder placement and angle. The farther back, the bigger it needs to be to have equal force. But it can also be shorter to achieve the same dump angle. And the angle of the cylinder is equally important. The more horizontal the cylinder, the less force in the vertical direction.

2. Just how Dump force you want.

3. What style. Singe cylinder? Dual cylinders? scissor mechanism?

As far as a power source, the 12v DC ones are usually slow, expensive, require some heavy gauge wire, and operate at a lower PSI which means bigger cylinders.

On mine, I used an air conditioner clutch to power an actual pump. It was faster, and could use smaller diameter cylinders cause it was greater pressure. AND could be operated from inside the truck. Some of the 12v units have a manual lever that requires you to get out.

IIRC, the pump, tank, filter, and DCV's was in the ~200 range.

I'll look and see if I can find my old thread on building mine. I think it is just what you need

 

[LD1]

Here is my old thread http://www.tractorbynet.com/forums/projects/158521-turning-1985-dodge-into-real.html

 

[Adamc44]

Hey thanks for the links. I was going to build my own flatbed. I have a pile of 6" & 4" c channel plus angle iron. I was
Thinking of doing a single cylinder but I like the looks of your setup.

 

[LD1]

Single cylinder is trickey on a truck, unless you use an expensive telescoping cylinder, or a scissor mechanism.

The driveshaft is in the way, and usually the gas tank as well. And a single cylinder would require a pretty beefy cross-member between the frame rails.

With all the junk in the way, and the cost of one large cylinder, it was easier and cheaper to use two smaller cylinders attached right to the frame. No complex cross member involved.

 

[LD1]

Single cylinder is trickey on a truck, unless you use an expensive telescoping cylinder, or a scissor mechanism.

The driveshaft is in the way, and usually the gas tank as well. And a single cylinder would require a pretty beefy cross-member between the frame rails.

With all the junk in the way, and the cost of one large cylinder, it was easier and cheaper to use two smaller cylinders attached right to the frame. No complex cross member involved.

 

[slowzuki]

Their are 2 problems with twin cylinder on the side like that though, because the fluid is free to move side to side there can be a bit more twist in deck when dumping off center loads. Other problem just that it makes room for side boxes tight. On LD1's truck he got lots of dump force as the flatbed sits up so high too, if your flatbed is tight to the tires it is much harder to get the angles good for a strong dump without having the cylinders hanging low or having poor dump angle. Lots of trade offs to decide on while building, I'm sort of stuck right now as I need to build one, want it low, want good dump angle, want to keep my factory receiver, allow for gooseneck, wondering how I can keep my current power tailgate if possible. Instead I keep using the rusty box and power tailgate.

 

[aczlan]

Their are 2 problems with twin cylinder on the side like that though, because the fluid is free to move side to side there can be a bit more twist in deck when dumping off center loads.

Would there be any more twist than one would see with a singe center mount cylinder?
Woulds a Rotary Flow Divider (such as: 0.11 CU IN 2 GPM 2 SECTION ROTARY FLOW DIVIDER MTE ) take care of this problem?

Aaron Z

 

[Oliver1655]

Did I understand you want to have a dump bed with a power tailgate & factory receiver? If you have a hydraulic operated tailgate, would you be able to use the same pump for the dump? Is the pump large enough?


LD1 - Did you ever change you cylinders from single acting to double acting?
For OP's benefit, if you have your cylinders single acting, you will have vents on the rod end of the cylinders. The negative of this is it will allow moisture to enter as the air moves in & out of the cylinder which will cause your cylinder to rust on the inside leading to early failure of the seals, pitting, hydraulic fluid to bypass the piston, ... I would strongly encourage you to make you cylinders double acting if possible.

 

[LD1]

Nope never did. I ended up selling that truck shortly after building it. Guy offered more than I could turn down, and I didnt use it often enough to justify keeping. All though it sure was handy.