Dump trailer doesn't have enough power

[4570Man]

The biggest downfall of a single cylinder set up is the low angle at start up. I have often thought about installing one or two short cylinders vertically at the front of the trailer to get the initial lift into motion. I have built two dump trailers and two dump bodies on F350's, all dump fine but the first dump trailer was 5'-8" x 10' with a single 4" cylinder, it would struggle for the first foot or so with a generous load of firewood or gravel. The second one I built I used a 5" cylinder, much better but it was also a 6'-6" x 12' trailer. Both of the Fords got 68" x 9' dumps, the first one had a large (guessing 6" bore) and never struggled, this one I have now I used a 4" cylinder, I suspect it will behave just like the first trailer I built (I haven't tested it with anything heavy yet)

Some good advice about taking more trips with smaller loads, you have to respect it for what it is. Turning up the pressure or upsizing the cylinder will just transfer the weak link to somewhere else.

My dads dump trailer is a single cylinder dump trailer and it’s not very strong. I have a ton dump truck with a cylinder cylinder and it will dump anything. The truck is a 5” cylinder and the trailer is like a 3.5” though.

 

[LD1]

With a dump trailer in the down position....then angle of the cylinder.....most of your force is trying to rip the trailer apart instead of dumping it. So I'd use caution increasing any capacity.

Perhaps post a pic of the current trailer with it dumped so we can see what we are looking at. What is the size of the current cylinder? And what is the empty weight and GVWR of the trailer?

 

[BeezFun]

A friend mounted a 4X4 on the front frame to give it a "head start" on the lift. I think it rattles loads to the back on long trips, but, it does make it easier to lift.

That would work good for me, I just use mine on our property behind the tractor.

 

[4570Man]

With a dump trailer in the down position....then angle of the cylinder.....most of your force is trying to rip the trailer apart instead of dumping it. So I'd use caution increasing any capacity.

Perhaps post a pic of the current trailer with it dumped so we can see what we are looking at. What is the size of the current cylinder? And what is the empty weight and GVWR of the trailer?

I’m actually surprised how well my ton dump truck has handled that. And it’s like a 5” cylinder so that’s a lot of force trying to rip it apart. But it’s been like that since 1992 so it apparently works.

 

[LD1]

I’m actually surprised how well my ton dump truck has handled that. And it’s like a 5” cylinder so that’s a lot of force trying to rip it apart. But it’s been like that since 1992 so it apparently works.

Cylinder that big is probably a scissor hoist. So on yours, it would be trying to rip the hoist itself apart and not so much the truck.

Steel has tremendous tensile strength. But With age and corrosion, I have seen scissor hoists ripped in half

 

[4570Man]

Cylinder that big is probably a scissor hoist. So on yours, it would be trying to rip the hoist itself apart and not so much the truck.

Steel has tremendous tensile strength. But With age and corrosion, I have seen scissor hoists ripped in half

My other trucks have a different setup but the ton truck just has the single cylinder with no hoist.

 

[endurodad2019]

anyone ever attempt a gas powered swap.....i have a 16' dump trailer and two battery setup .
some days i get one dump some days have a dump so looking to swap in a gas powerd unit

 

[LD1]

anyone ever attempt a gas powered swap.....i have a 16' dump trailer and two battery setup .
some days i get one dump some days have a dump so looking to swap in a gas powerd unit

I wired mine right to the truck battery with heavy gauge cable. Like 1/0 or 1ga or something.

They are made for winches and stuff. Have anderson connectors on the ends. I no longer worry about the trailer battery

 

[Fxfymn413]

Our OP seems to have fallen by the wayside. I'm a little surprised he would give a lift capacity of 3K with a tandem axle 6x10 trailer. It seems that it would be more like 3 tons. With a quick look at what pops up on-line the least net weight I could find was 4400 lbs. with most running over 7K.

 

[grsthegreat]

Weird….i have had my 6x10 dump full of sand, and it dumped just fine. No issues at all.

 

[retNAVY]

The biggest downfall of a single cylinder set up is the low angle at start up. I have often thought about installing one or two short cylinders vertically at the front of the trailer to get the initial lift into motion. I have built two dump trailers and two dump bodies on F350's, all dump fine but the first dump trailer was 5'-8" x 10' with a single 4" cylinder, it would struggle for the first foot or so with a generous load of firewood or gravel. The second one I built I used a 5" cylinder, much better but it was also a 6'-6" x 12' trailer. Both of the Fords got 68" x 9' dumps, the first one had a large (guessing 6" bore) and never struggled, this one I have now I used a 4" cylinder, I suspect it will behave just like the first trailer I built (I haven't tested it with anything heavy yet)

Some good advice about taking more trips with smaller loads, you have to respect it for what it is. Turning up the pressure or upsizing the cylinder will just transfer the weak link to somewhere else.

What do I look for on the pump(markings) to make sure it could handle a larger cylinder?

 

[retNAVY]

Our OP seems to have fallen by the wayside. I'm a little surprised he would give a lift capacity of 3K with a tandem axle 6x10 trailer. It seems that it would be more like 3 tons. With a quick look at what pops up on-line the least net weight I could find was 4400 lbs. with most running over 7K.

You could be correct,you've got me guessing now...here are some of the specs ..
6″x10′ BLACK Griffin Deck Over Dump Trailer

7,000#lbs GVWR (Gross)
3,500#lbs GAWR (AXle)double axle
2,000#lbs Curb Weight
5,000#lbs Payload

 

[LD1]

What do I look for on the pump(markings) to make sure it could handle a larger cylinder?

The pump dont care what size cylinder it is hooked to. Its gonna make a given PSI and thats it. Larger cylinder has greater piston area.

If your pump makes 3000PSI and you have a 4" cylinder.....the area of that cylinder is 12.56 square inches. So a 4" cylinder bore could generate a force of 37680 pounds.

Going to a 4.5" cylinder has 15.9 square inches. Same 3000psi pump could make the cylinder push with a force of 47,689 pounds.

And a 5" cylinder would be 58,875 pounds of foce.

The only thing regarding the pump is that it holds enough oil to account for the bigger cylinder without running dry.

But even a small increase in cylinder size is a huge increase in cylinder force. But due to the angle.....only a small part of that force is trying to lift the dump trailer. A much greater portion of that force has to be absorbed by the trailer frame. So make sure the trailer can actually handle the added stress

 

[Rustyiron]

anyone ever attempt a gas powered swap.....i have a 16' dump trailer and two battery setup .
some days i get one dump some days have a dump so looking to swap in a gas powerd unit

The best, most reliable dump trailer that I've ever used had a small Honda and a 2 stage log splitter pump.
I don't know why this isn't an available upgrade. It may be, I gave up on dump trailers a long time ago and haven't shopped them.

 

[4570Man]

The best, most reliable dump trailer that I've ever used had a small Honda and a 2 stage log splitter pump.
I don't know why this isn't an available upgrade. It may be, I gave up on dump trailers a long time ago and haven't shopped them.

If I was actually trying to do work with mine I would Honda swap it. As it is now I use my dump truck for heavy loads.

 

[davedj1]

The pump dont care what size cylinder it is hooked to. Its gonna make a given PSI and thats it. Larger cylinder has greater piston area.

If your pump makes 3000PSI and you have a 4" cylinder.....the area of that cylinder is 12.56 square inches. So a 4" cylinder bore could generate a force of 37680 pounds.

Going to a 4.5" cylinder has 15.9 square inches. Same 3000psi pump could make the cylinder push with a force of 47,689 pounds.

And a 5" cylinder would be 58,875 pounds of foce.

The only thing regarding the pump is that it holds enough oil to account for the bigger cylinder without running dry.

But even a small increase in cylinder size is a huge increase in cylinder force. But due to the angle.....only a small part of that force is trying to lift the dump trailer. A much greater portion of that force has to be absorbed by the trailer frame. So make sure the trailer can actually handle the added stress

Well said!
Here is what I did on the one with the 5" cylinder, first it was a double acting cylinder but a power up, gravity down pump so I welded a bung into the reservoir of the pump and ran a hose to the top port on the cylinder. After cycling it a few times and adding transmission fluid the unused part of the cylinder became part of the reservoir thereby not needing a huge tank. As the pump pushed the cylinder up, the fluid would get pushed out the top port and back into the tank, when going down the fluid went from the bottom port to the tank and the top port siphoned the fluid out of the tank to the cylinder, worked great. On my dump truck I decided to go with power up and power down. I love it so far. Gravity down can be real sloooooow in sub-zero weather even using ATF.

Edit to add: DC Power Units | Hydraulic Power Units | Hydraulics | www.surpluscenter.com
power packs come in different volumes also, more gpm's equals faster times. Of course the larger the cylinder the slower it will be too.

 

[LD1]

Well said!
Here is what I did on the one with the 5" cylinder, first it was a double acting cylinder but a power up, gravity down pump so I welded a bung into the reservoir of the pump and ran a hose to the top port on the cylinder. After cycling it a few times and adding transmission fluid the unused part of the cylinder became part of the reservoir thereby not needing a huge tank. As the pump pushed the cylinder up, the fluid would get pushed out the top port and back into the tank, when going down the fluid went from the bottom port to the tank and the top port siphoned the fluid out of the tank to the cylinder, worked great. On my dump truck I decided to go with power up and power down. I love it so far. Gravity down can be real sloooooow in sub-zero weather even using ATF.

Edit to add: DC Power Units | Hydraulic Power Units | Hydraulics | www.surpluscenter.com
power packs come in different volumes also, more gpm's equals faster times. Of course the larger the cylinder the slower it will be too.

Yep. A true single acting cylinder needs a pretty big reservoir. Bigger than most little 12v power units have.

A typical scissor lift is something like a 5.5x20 cylinder. Cylinder alone takes 2 gallon of fluid.

Even my little suretrac with I think a pair of 3" x 24" cylinders takes a gallon and a half.

Thats the single biggest reason most dump trailers are power down. Not because they need to be power down. But it requires less fluid. Instead of having to fill the entire cylinder with oil....you only have to make-up for the volume of the rod leaving the cylinder.

In my case, 1.5" rods x 24" stroke. So the pair of them....to fully extend, now only requires a reserve of about a quart and a half instead of a gallon and a half.

And the above example with a 5x5x20 cylinder.....assuming it had a huge 2.5" rod....would only need to account for just shy of 2 quarts of oil. Which is about all most of them little power units hold

 

[Fxfymn413]

5,000#lbs Payload

If the payload is 5K it should dump 5K. Have you checked the pump to ensure it is hooked up correctly? Mine really fooled the dealer. He could get it to dump with it empty, and it would raise a less than full load, but as soon as I put a real load on it it would not raise.

 

[CADplans]

My trailer is 6.5 feetX10 feet,, you can estimate the height,,
I can dump my trailer when it is level full to the top of the boards with freshly dug creek stone/sand.

I know when it is full,, it is ALL that my 3/4 ton Chevy with 4.10 axle will pull up a pretty steep local road.

Yes, I know I was overloaded,, but, it was a VERY local haul, well under 10 miles.

 

[CADplans]

Hey, retNAVY,, where do you live? (what state?)

I too was certified to weld pressure hull when I was in the US Navy,, C1 welding school.
But, that was never needed to keep the destroyer running that I was on LOL!!

I sure did burn a LOT of rod in welding school,, WOW!!