BACKHOE DILEMMA

[billblough]

Just had a very concerning problem with my backhoe. Was digging out a stump, had all the roots around the stump cut, turned the stump on it's side.
While pulling it onit's side the weight of the stump changed and instead of pulling away from the tractor it pushed toward it. This would not have been a problem except for the fact that this happened at the top off the raising of the boom. When the weight changed it put pressure on the boom and caused it to overtravel the cylinder and to lock itself in place. The boom would not raise or lower..

I thought I had bent the cylinder or the boom. Maybe I have? I pulled the tractor over to a tree and chained the tip of the lower boom to the tree and slowly drove forward. It did pull the boom past the cylinder travel and allow the piston to work the boom again.

I will be very careful in the future when moving a large stump.

By the way I have a Kubota l3400HST with FEL and BH75.

I feel lucky to not have ruined the backhoe.

[john_bud]

I've seen reports here on guys doing the same thing with the kubota hoe, it seems to have been built right at the edge of stability and can be easily driven over center.

Is it possible to fit a mechanical stop to keep it from happening? I know you could fit a cylinder stop,but you would loose some lift.

jb

[wushaw]

Interesting, I have not done that one, although I did bend the curl cylinder once doing something I probably shouldn't have been doing and haven't done it since.

[justcountry]

I have a 3130 with the bh90, and I have also bent the bucket cylinder, but I have no idea what you mean by locking itself into place? which cylinder was it?

[billblough]

It was the main boom cylinder. If you raise the boom the boom will raise until it is stopped by the piston. If enough upward pressure is applied it will push past the travel of the piston and the angle of the piston will not give the mechanical advantage to lower the boom. The steel in the boom or something has to spring in order for this to happen. Hopefully I haven't permanently damaged anything. I have used the backhoe since this happened and all seems fine.

I will feel better when I have another 50 hours on the tractor without noticing any problems.

I never thought this could or would happen, but now that it has to me it makes sense. I think I will try to make a stop to limit the travel of the boom in the upper direction. Or maybe just be smarter when using the backhoe.

I sometimes tend to push the limits of equipment and it tends to catch up with me if I do it often enough.

[madslick]

Originally Posted by billblough

It was the main boom cylinder. If you raise the boom the boom will raise until it is stopped by the piston. If enough upward pressure is applied it will push past the travel of the piston and the angle of the piston will not give the mechanical advantage to lower the boom. The steel in the boom or something has to spring in order for this to happen. Hopefully I haven't permanently damaged anything. I have used the backhoe since this happened and all seems fine.

I will feel better when I have another 50 hours on the tractor without noticing any problems.

I never thought this could or would happen, but now that it has to me it makes sense. I think I will try to make a stop to limit the travel of the boom in the upper direction. Or maybe just be smarter when using the backhoe.

I sometimes tend to push the limits of equipment and it tends to catch up with me if I do it often enough.

Check your email Bill,
I emailled you something concerning a fix for this...

Later...

[Willl]

Originally Posted by madslick

a fix for this

How 'bout sharing it to the rest of us ?

[oldhippy]

Originally Posted by wushaw: Interesting, I have not done that one, although I did bend the curl cylinder once doing something I probably shouldn't have been doing and haven't done it since.



Can you do something wrong? big dan

[wushaw]

Yes I belive I can, carry too big of a stump with the BH and hit some rough terrain going to brush pile with the weight of the stump hanging in the bucket and the curl cylinder extended pretty far, I belive it was a little too much for it.
I didn't notice it till I was diggin up the next stump, so I don't carry heavy stumps in bucket anymore and haven't bent another curl cylinder since.