bent hydraulic ram on woods backhoe

[traditions]

Has any one ever bent the top boom ram on a woods backhoe ? We have bent two,and it has happened to my son both times. The ram bends down towards the frame, so it cant be when the ram is pulling in. I said he had the bucket low and caught it on the ground when he was moving the tractor, but he said he didn't move it the second time. It doesn't seem possible that there is enough hydraulic power to bend the ram pushing out with the bucket. I just don't see how the ram keeps getting bent. Thanks for any help

 

[BAP]

Could be your son was using the backhoe to move the tractor. Pretty common for backhoe operators to pick up the back of the tractor with the boom and push it forward. With a large commercial backhoe this is not such a problem because they are built rugged, on a hoe the size of yours it could potentially be a problem because they aren't as rugged.

 

[D2Cat]

Could be your son was using the backhoe to move the tractor. Pretty common for backhoe operators to pick up the back of the tractor with the boom and push it forward. With a large commercial backhoe this is not such a problem because they are built rugged, on a hoe the size of yours it could potentially be a problem because they aren't as rugged.

Yep, sure looks like it!

 

[traditions]

He was digging a culvert trench, that was pretty deep, so it was a long reach. The ram does push when retracting the boom, so I guess that is what happened, maybe the angle when at the bottom of the trench. You don't really know when its bending, until its too late. He wasn't lifting the tractor when it bent, digging from the side of the trench. I just don't see how the hydraulics have enough power to bend the ram. Maybe have the idle set a little lower next time. Thanks for the reply

 

[cerlawson]

The son needs some simple structural static rules. In a long reach of the upper arm the upper ram could would not be extended. It would have great debility to take compression force. However the longer the extension of ram, the less compression load it can withstand. The bending took place when the arm was well down, near vertical, not horizontal, meaning the ram was well extended, its weakest position for compression load.. Perhaps too much pull of the bucket towards the tractor when down there. Also driving forward and the bucket down in the trench would do it, more likely what happened..

The shorter the ram extension, the less chance it has for bending under a compression force. It's the same capacity principle of building columns. The longer the column, the lower its ability to carry compression load (Assuming no width change).

 

[coachgeo]

Simple way to keep it from happening again......
1. admit that.... First time he did it.. shame on you... ... second time. SHAME ON HIM... ... thus,
2. he pays for repair

Tuff love, Bettya he'll never bend it again

PS- Yeah I know I bastardized that quote

 

[Ike]

You can straighten that out in a hyd press as long as the chrome is not cracked

 

[boz1989]

I would really like to know how this happened, because I have been looking at buying a woods backhoe. In my opinion, this shouldn't be possible using the hydraulics, no matter what you are doing. Now, if you are driving with it hanging out the back, and it snags something, that might be excusable.

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[Sammy3700]

I agree with IKE. We have straightened them in worse shape than that one looks to be.

 

[BAP]

Digging, matter how deep or the angle shouldn't bend the cylinder. Could be the material in the ram is not strong enough or could be the relief valve for the backhoe is not working or set to high? I would have a hydraulic pressure test done to check it out before using it again to make sure.

 

[Tarmy]

The only thing I can figure...is that the hyd cylinder is made from cheap(er) or thinner materials. There is no way that should bend...unless it was weakened before you got it...or the damage from the first bend and fix simply weakened it too..

I have the BH 76 frame mount...and I absolutely beat the hell out of it...wrench on big boulders and deep trenches. I never even think twice about letting up on it in any position I can extend it...never had any issues.

Good luck..but even if you replace that ram...with a better or new cylinder...you may simply repeat the problem...

 

[cerlawson]

The question as to how this can happen is one that might be explained. First of all it is unlikely that the hydraulic pump could develop enough pressure to cause it. So with the control valve shut is there any pressure relief valve in the cylinder system in that case with pressure built up in the cylinder with the ram being pushed in? Probably not. So with the tractor driving forward, the bucket in the tench grabbing into the undug bank, there is no pressure relief far above operating pressure as the ram is being shoved into the cylinder. So the story now is "You never drive forward to a new position with the bucket anywhere near an obstruction or where it might dig as you move".

 

[Ike]

This is what I think happened as I have seen it on my JD. With the boom in the hole and you lowed the bucket then uncurled it in the hole putting pressure on the boom cyl, I bent my boom once a long time ago doing this. It won't bend again in that spot anyway

 

[traditions]

I am not blaming this on my son. It just happened to be him the second time using the machine. We weren't sure that he snagged the boom the first time, but assumed that was what caused it. We didn't expect it to be a ongoing problem. I just put a block of wood under the ram and extended the ram out, and straitened it back out, and it straitened out fine. The chrome is scratched pretty bad, so it will only be a matter of time before it starts leaking. The first ram was bent way worse, and closer to the end. That's what makes me wonder if its just the geometry of the back hoe. I think that the rams are made from soft metal, both times they have bent was after digging for a while, and they were pretty hot. I could have a ram made here, and maybe get a better product. Thanks for the answers.

 

[Tooljunkie]

My buddy and i were discussing a similar issue, moving machine with bucket engaged in the ground is a big no no. Even with big excavators, can break the boom. Going up in diameter may prevent this from happening again,but could destroy something else if its used in the same manner.

 

[traditions]

Well , I was digging up a stump yesterday, and I bent the ram again. I would say the material that the ram is made from is soft. I think when it gets hot it loses its strength. I was digging around the roots with the rpm at 1400, keeping an eye on the ram, and it all seem to be going good. I was almost done when I heard a screech, and looked and the ram was bent. I was just digging along , doing nothing out of the ordinary. I think I may see if I can get a ram from a Kubota hoe to fit , and see how it works. It doesn't seem that it would be just this hoe that has the problem.

 

[North Idaho Wolfman]

Was the ram that bent a Woods OEM cylinder?

 

[Tunaslayer]

First off, has the hydraulic cylinder been straightened twice? If so, there is some metal fatigue going on. If not, I would point to North Idaho Wolfmans question, and say it was not burly enough for a backhoe. It sucks when an expensive piece lets you down, I can relate. Hopefully it can be resolved.


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[traditions]

The ram I bent was a replacement from the farm equipment place,that sells Woods , and the first one was the original that came on the back hoe. They look identical. The only thing we did different was switch the controls so they operate like a deere. I wonder if that has some thing to do with the relief

 

[Tunaslayer]

I think you just figured it out. Hopefully the hydraulic gurus can confirm, but I doubt the relief works on the wrong side of the valve.


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