I have a 5 ton GN sissor dump, dump trailer...the box is 16ft long and sometimes when loaded with dirt its very hard to dump...has anybody ever added a 2nd hydraulic cylinder up near the front of your dump trailer to give it that extra push to get it going?

kinda like a telescoping cylinder found in heavier dump trucks

ive heard of winches mounted on the top of the gooseneck to help lift it before the main lift takes over...

 

I you are overloading the ram you are probably overloading the rest of the trailer as well. Putting on more ram will help you dump but you're just moving the problem down to the next weak link, frame, tires, axles, box hinges, etc. Might be time for a bigger trailer.

 

have you tried to turn up the pressure a little?

 

I have to agree ..... time to move up to a better dump trailer.

 

Yup, what ^they^ said.

But yes, I have seen an assist cylinder on a few dump trailers. I installed one per a customer request too. All I did was get a 24" cylinder and made a mounting base and a 'stop' plate on the front of the trailer frame and dump body respectively. The cylinder wasn't attached to the body, just the frame. It would help push the body up that first 2 feet, after that, the main scissor lift had enough 'umph' to keep it going. Guess it works ok, the customer was happy. I saw it a few years later and the only thing he complained about was the fact that the dump body had begun to bend. It was trying to form itself into a 'U' from front to back and would no longer sit flat on the frame, causing it to kinda 'rock' when it went down the road empty. Oh well, I did what I Was asked!

 

trailer is big enough as it is, that wasnt my question...the position of the hoist its just not far enough towards the front...it dumps fine, just when have those mixed loads of dirt with stone is when it struggles...

chaikwa,was the customers trailer you built have 2 pumps? as in one for each cylinder? i was thinking of excatly what you described, but how did you involve the extra cylinder..one switch operated both? what happend when the front ram was out of length did it just keep trying to operate while the main hoist was in action?..thats what i dont understand

 

OK my turn.
1. What is the operating pressure of the pump? Actual and Factory spec.
Pump may be leaking internally and will loose hydraulic pressure and flow. This will need to be service.

2. Is this a single acting cylinder?

3. Are you lifting on the Head end of the cylinder or the Rod end?

4. Does the cylinder need to be repacked? Hydrualic fluid leaking past head end or rod end seals. Will cause you to lose operating pressure and thus the cylinder will not be able to lift the load. You can check this by using an IR gun and see if a ceratin area has a higher tempeture then the rest of the cylinder. As the cylinder is raising the dump body.

5. Is the relief valve working correctly and at the correct pressure?

I like to rule out any hydraulic issues before installing an additional cylinder, due to the expense of a new cylinder and the components to actuate this cylinder.
Jim W.

 

2X. Check you hydraulics first. As components age and wear the internal leakage becomes greater you don't see it unless you go looking for it. Change your filters pressure and return if you have both. As stated check the temp of the return line from the cylinder as the cylinder is a prime candidate for internal leakage.

 

It is probably a standard 3000 psi circuit, that would have no problem going to 3500 psi without any thought. You may need to invest in a different pump, but probably just need to change the relief pressure of the pump. A allen head key & lock screw will be somewhere on the body that you should be able to adjust. Make sure you put a pressure gauge in line too! but you will easily be able to get there without too much effort.

If you need more lift than a couple hundred PSI, then it seems like you are overloading the unit....if you need a 2nd cylinder to help-at a 2" diameter will push another 9500lbs.....

just my $.02.

 

Unfortunately, most manufacturers only do what they have to in order to sell trailers. In other words, your dump trailer might have a load capacity of 12,000 pounds, but that's not saying it will lift that much weight. Most people won't load it that heavy, so instead of spending the extra $1000 for a decent hoist that will surpass the load capacity by 1/3, they'll install a hoist that will lift 2/3rds of the trailers load capacity and save money in the process.

The one I built had one pump. I tee'd into the main hydraulic line coming off the pump and ran one line to the small cylinder in front and the other line to the scissor lift. Pressures are the same in both lines because they're tied together. When the small front cylinder reaches its' stroke limit, it just stops. Nothing wrong with topping out a cylinder, the pressure is no greater in the small cylinder than it is in the scissor lift cylinder. The only 'fly-in-the-ointment' is I am assuming that your trailer has a double acting cylinder in your scissor hoist. This too is a manufacturers way of saving a few bucks; they don't need a large hydraulic reservoir with a double acting cylinder because half of what is being put into a cylinder to achieve lift, is being returned to the sump from the top of the cylinder. This means,usually, that you have power up and down. You drain your battery twice as fast because you essentially have to pump the body down as well as up. Not my choice of ideal systems and I won't build that way. I *think* you could adapt a double acting cylinder into this system as well tho, you'd just have to experiment with tapping into the hydraulic lines running the scissor hoist to get the front cylinder to work. Shouldn't be a big deal. The one I modified for my customer miraculously had a single acting cylinder in it to begin with, so it simplified my job significantly. (power up, gravity down)