What's causing this to bend?

[farmerdan7618]

On a 16 ton JPM dump trailer of 2005 vintage. Hydraulic tailboard rams bending for some reason and can't quite fathom it. Always done it, replaced the ram and the new one bent straight away.

 

[njneer]

On a 16 ton JPM dump trailer of 2005 vintage. Hydraulic tailboard rams bending for some reason and can't quite fathom it. Always done it, replaced the ram and the new one bent straight away.

Take pins out and see if the ram
Is at full stroke when door is shut .
Looks to me that you have stroke left on the ram when the doors shut and it is continuing to push when doors shut.

 

[kill]

Top pin bent as well?

 

[farmerdan7618]

Top pin bent as well?

Don't think so, looks ok.

 

[farmerdan7618]

Take pins out and see if the ram
Is at full stroke when door is shut .
Looks to me that you have stroke left on the ram when the doors shut and it is continuing to push when doors shut.

Could well be, got to take the ram off so will check. Would this cause the ram to bend the other way though?

 

[njneer]

Depends on which way it starts to over centre when starting to bend .
Definitely a compression bend which can really only happen by the ram pushing against a stop.
The weight of the door and the relative pivot point will have a continuous tension force on the ram ie it is continuously pulling on the ram.

 

[Lincsman]

How well lubricated is the top pivot pin?

 

[grass man]

Could well be, got to take the ram off so will check. Would this cause the ram to bend the other way though?

Before you remove the ram pull out the top pin, hold or tie ram against outside of the tailgate bracket and extend fully to check it's extended length beside what it actually needs to be

 

[snipe]

when you tip the trailer up, is the bottom of the backdoor being pushed into the top of the heap. if it is a solid material(stone or rubble) that you are moving the back door wont be able to sink into the pile. causing the backdoor to push against the rams....or is there some soil building up under the back door so i wont close fully

 

[Dave W]

Take pins out and see if the ram
Is at full stroke when door is shut .
Looks to me that you have stroke left on the ram when the doors shut and it is continuing to push when doors shut.

This ^^
Plus the ram looks far to small a rod imo

 

[shumungus]

When the door is shut, is there any clearance between the clevis on the end of the ram rod (where the pin with the big R clip is) and the red plate/arm of the trailer?
If there isn't this would bend the rod, it seems strange that rod bent near the end and not in middle.

 

[2wheels]

On a 16 ton JPM dump trailer of 2005 vintage. Hydraulic tailboard rams bending for some reason and can't quite fathom it. Always done it, replaced the ram and the new one bent straight away.

thought is was bald rick posting going by the title

 

[puntabrava]

Looking at the bend you would say it’s trying to close with an object stopping it from full closing.

 

[Mr Happy]

On a 16 ton JPM dump trailer of 2005 vintage. Hydraulic tailboard rams bending for some reason and can't quite fathom it. Always done it, replaced the ram and the new one bent straight away.

Piston rod to small and work pressure to high.

 

[Andrew]

Take pins out and see if the ram
Is at full stroke when door is shut .
Looks to me that you have stroke left on the ram when the doors shut and it is continuing to push when doors shut.

This. Several solutions.
1) Step up a rod size and hope there’s enough piston area left to open the door.
2) Fit a pressure relief valve to the cylinder end.
3) Get a new rod made however much shorter it needs to be. Maybe get the end threaded so you have fine adjustment.

Note options 2 and 3 may still bend if you tip up with a load in.

 

[snipe]

When the door is shut, is there any clearance between the clevis on the end of the ram rod (where the pin with the big R clip is) and the red plate/arm of the trailer?
If there isn't this would bend the rod, it seems strange that rod bent near the end and not in middle.

Yes, the rod been bent at the top and not in the middle. Looks like this is happening when the ram is two thirds retracted.

 

[eagleye]

could it be catching on the side of the clevis causing the clevis to want to twist sideways instead of staying straight on the end of the rod? maybe not explaining very well.
take pin out of clevis. when door closed and ram fully extended will it fit back in easily?

 

[shumungus]

Studied it again in photo. You say you replaced the ram and it bent straight away and didn't bend any worse than this. I still think it is related to the clevis. Is there a point/tail on the end of the red arm of the trailer past the pin with R clip? If so does it foul the ram clevis when the tail door is near fully open, if so this would twist it in such a way to cause this bend. More close up photos please.

 

[Sharpy]

Studied it again in photo. You say you replaced the ram and it bent straight away and didn't bend any worse than this. I still think it is related to the clevis. Is there a point/tail on the end of the red arm of the trailer past the pin with R clip? If so does it foul the ram clevis when the tail door is near fully open, if so this would twist it in such a way to cause this bend. More close up photos please.

This. And a video of the door opening and closing.

 

[sawdust]

Studied it again in photo. You say you replaced the ram and it bent straight away and didn't bend any worse than this. I still think it is related to the clevis. Is there a point/tail on the end of the red arm of the trailer past the pin with R clip? If so does it foul the ram clevis when the tail door is near fully open, if so this would twist it in such a way to cause this bend. More close up photos please.

This. And a video of the door opening and closing.

And the clevis would be better on the door and a single eye on the ram rod for better movement and less chance of fouling.