Green Tractor Talk banner

1 - 13 of 13 Posts

·
Registered
Joined
·
12,487 Posts
Discussion Starter #1
hello-my youngest son has built a dump trailer, only to find his pump and cylinder will not work. now when he and his buddy hot wired it off the trailer, it lifted him up. now this pump and cylinder we have no way telling how old it is, only to go off the man that owned it before, and my son saw it work when it was mounted on a different truck.

we loooked for a tag no., on the case -none. it had some type of a screw and a plunger type thingee with some o-rings on it. but i do not see anything to let the air out, so the trailer will sit back down. jus thought i would run ideas past all of u fellas first. thanks-big jim-gotta go, been up all night watching son build this trailer of his-later.
 
  • Like
Reactions: vacruiser

·
Registered
Joined
·
5,642 Posts
What goes up. . .

hello-my youngest son has built a dump trailer, only to find his pump and cylinder will not work. now when he and his buddy hot wired it off the trailer, it lifted him up. now this pump and cylinder we have no way telling how old it is, only to go off the man that owned it before, and my son saw it work when it was mounted on a different truck.

we loooked for a tag no., on the case -none. it had some type of a screw and a plunger type thingee with some o-rings on it. but i do not see anything to let the air out, so the trailer will sit back down. jus thought i would run ideas past all of u fellas first. thanks-big jim-gotta go, been up all night watching son build this trailer of his-later.
There has to be a valve somewhere to allow the hydraulic fluid to flow back. It could be a manual valve or electric but there has to be one. It could even be built into the pump assembly. The previous owner could probably tell him where it's located.

Treefarmer
 
  • Like
Reactions: BigJim55

·
Administrator
Joined
·
20,865 Posts
A couple of pics would be very helpful in letting us help you. :good2:
 

·
Super Moderator
Joined
·
5,197 Posts
but i do not see anything to let the air out, so the trailer will sit back down.
Air? Is this a pneumatic lift or hydraulic lift?

I have a single-acting hydraulic cylinder on my dump trailer. The valve system is all enclosed in the same box as the hydro pump but essentially, the pump kicks in and the valve opens to pressurize the cylinder to lift the dump bed. When I select the "Down" mode, the valve opens but the pump doesn't operate. That allows the weight of the dump body to force the hydro fluid out of the cylinder, through the valve and back into the reservoir.

I would think most pneumatic systems would operate on a very similar premise.
 

·
Registered
Joined
·
12,487 Posts
Discussion Starter #5
There has to be a valve somewhere to allow the hydraulic fluid to flow back. It could be a manual valve or electric but there has to be one. It could even be built into the pump assembly. The previous owner could probably tell him where it's located.

Treefarmer
yeah we thought of that too, but the boy has had this for 2yrs already laying in his corner of garage, and we believe things are missing from it, they tried it hooking jumper cables to it before hand, it went up once,it is old, he thought he had a million bucks with it-u know the feeling -right

A couple of pics would be very helpful in letting us help you. :good2:
yeah-i know-and i will try tomorrow to get some-running blind here:munch:

Air? Is this a pneumatic lift or hydraulic lift?

I have a single-acting hydraulic cylinder on my dump trailer. The valve system is all enclosed in the same box as the hydro pump but essentially, the pump kicks in and the valve opens to pressurize the cylinder to lift the dump bed. When I select the "Down" mode, the valve opens but the pump doesn't operate. That allows the weight of the dump body to force the hydro fluid out of the cylinder, through the valve and back into the reservoir.

I would think most pneumatic systems would operate on a very similar premise.
not air-same kinda deal as a snow plow set up. he did say it had a push button to raise it, but really didn't know how it came down:dunno:i told him it had to have some sort of manual valve to drop it back down. u know- no operating manuals with it, not that my son didn't have enough time to come up with one, in 2 yrs-thanks oh
 
  • Like
Reactions: gbnpp05

·
Registered
Joined
·
747 Posts
Did he figure it out?

On some single acting, gravity down systems there is only one line going to the bottom of the cylinder and the top port just has a breather on it. If you capped that port instead of allowing it to breath it could cause it to not come back down.
 

·
Registered
Joined
·
5,642 Posts
Not sure on cap

Did he figure it out?

On some single acting, gravity down systems there is only one line going to the bottom of the cylinder and the top port just has a breather on it. If you capped that port instead of allowing it to breath it could cause it to not come back down.
I don't think the ram would expand either, unless you extended it and then capped the breather. The air has to be able to leave the ram or you have hydraulic pressure on one side, air pressure on the other. You might compress the air some but couldn't fully extend the ram.

Treefarmer
 

·
Registered
Joined
·
2,966 Posts
Generally with these systems lifting runs the pump motor through a directional valve that is not energized or shifted so it is in its "normal" position. To lower you have to energize or shift the valve. This type of operation is typical so that a loss of power would not result in a load dropping.
 

·
Registered
Joined
·
12,487 Posts
Discussion Starter #9
results

ok-fellas it is working now. he took the line off cylinder and used air to cylinder and at 100psi it went right up. last evening his buddy got the little rod unstuck from the bigger valve:dunno:IDK-what the correct word would be called that screws down inside the pump.. but today he replaced the o-rings on both pieces, and he found 2 small bearings with a small spring still suck in the bottom of the hole. he put everything back together hooked hose back to cylinder. hooked juice to pump and it went right up. and when he moved the rod it came back down, now he said it went down slowly, but likely may have some air in it yet. so he just has to fix a switch to make it go up, and a new lever of some sort to go down, he is happy, so thanks will show uns pics when done-ok
 

·
Registered
Joined
·
452 Posts
Big Jim...i think they all return/drop slowly when the trailer is empty. They likely restrict the return flow of the hyd fluid to cushion the bed drop.
 
  • Like
Reactions: BigJim55

·
Registered
Joined
·
5,642 Posts
Slow drop

Big Jim...i think they all return/drop slowly when the trailer is empty. They likely restrict the return flow of the hyd fluid to cushion the bed drop.
I agree. Mine is almost new and it's been that way from the beginning. I really don't want it to slam down. It is a very handy piece of equipment though. I knew I would use it but didn't realize how frequently it would come in handy. Moving brush, dirt, stone, firewood, old fence debris all just got easier. In many cases, I can load with the tractor and FEL, dump where I want and not actually touch anything by hand.

Treefarmer
 
  • Like
Reactions: BigJim55

·
Super Moderator
Joined
·
5,197 Posts
Big Jim...i think they all return/drop slowly when the trailer is empty. They likely restrict the return flow of the hyd fluid to cushion the bed drop.
To some extent that is how mine is. Mine was MUCH slower at first though. I had to cycle the cylinder about 20 times to get all the air out of the system initially. During those cycles it was painfully slow coming down. (As in, 30 seconds to raise to full height, 30 minutes to drop back down.) Each cycle got a little faster until it purged and now the time to go up or down are about equal.
 
  • Like
Reactions: BigJim55

·
Registered
Joined
·
12,487 Posts
Discussion Starter #13
Big Jim...i think they all return/drop slowly when the trailer is empty. They likely restrict the return flow of the hyd fluid to cushion the bed drop.
yeah-i believe that too, heck look at a tri-axle, them beds come down slow too.

I agree. Mine is almost new and it's been that way from the beginning. I really don't want it to slam down. It is a very handy piece of equipment though. I knew I would use it but didn't realize how frequently it would come in handy. Moving brush, dirt, stone, firewood, old fence debris all just got easier. In many cases, I can load with the tractor and FEL, dump where I want and not actually touch anything by hand.

Treefarmer
well this is pretty old according to the fella i talked to in Illinois , where they rebuild them, or give u info for the type of pump u have. he said he had to lay like a 10lb. sledge hammer on the frame to get it started, but once it started it dropped the whole way down. i told him wait till he gets the floor on, and the sides, and i bet it will probably drop a lot easier with the extra weight. he is so tickled just to see it coming alive:laugh: and hey i am too-cause i can use it too. his buddy's trailer is a 6 by 10-rated @ 12,000lb. now don't hold me to that for sure-ok. but to dump better into it, i got him to pull the wooden sideboard, even at that, when it started filling up, i had to take the bucket and help the dirt to the otherside of bed, or i guess i could of drove around to the otherside, and dumped into the bed.

my boys dump trailer has them under slung axle's under it, boy does it seem to sit low to the ground, i will not have any trouble dumping into it at all. yes-we need pics of it-will try to get some before the floor gets tacked on and sides-ok:lol:
 
1 - 13 of 13 Posts
Top