Bent a piston rod in my boom cylinder

[Frankman]

I did crack the weld on the boom... I was using the bucket to break a pretty good size root.. I really do not understand how it happened as I have done the same technique literally a hundred times or more.. I just got under the root and curled the bucket to snap it.. I heard a bang which was obviously when the weld cracked on the boom.. Not a happy camper....

 

[wdchyd]

In order to bend a shaft that is extended, you use another cyl/component and a mechanical advantage to apply more force.

What would happen if you bury the bucket 6 ft in the ground and tried to back the BH about 8 ft. the work port reliefs might go off, or the force might blow a hose or burst a fitting.

Mechanical forces are now involved by generating hyd force, and mechanical force. You might have a 10 to 1 relationship on the dipper to the boom.

JJ nailed it.....it's called an induced load (forces from another puts too much force on the bent cyl)

Leverage is the culprit......work port reliefs are the cure (too late in this case)

as long as the gland is not egged out (check sloppiness when rod is extended out, it's a routine repair for a good hyd shop

http://www.tractorbynet.com/forums/hydraulics/203400-3-minute-hydraulic-rod.html

 

[jerrybob]

If a shop can't repair....try these guys....I've had good luck with them. Surplus Center - Hydraulics, Engines, Electrical and More

 

[Frankman]

Anyone know if I should have a concern with the dent and cracked weld in the boom.. Do I need to try and repair the dent, or will I be ok just re welding her up?

 

[wdchyd]

I would just weld it up, maybe add a reinforcement plate if I felt like the weld isn't enough

 

[Frankman]

That's pretty much what I was thinking also... Maybe put a plate over it after I re weld it.

 

[magicheater]

I did crack the weld on the boom... I was using the bucket to break a pretty good size root.. I really do not understand how it happened as I have done the same technique literally a hundred times or more.. I just got under the root and curled the bucket to snap it.. I heard a bang which was obviously when the weld cracked on the boom.. Not a happy camper....

I had a similar event last summer using my hoe, difference was I blew a hose instead of bending a cylinder rod. A similar thing happened when I was grubbing a stump with my toothed bucket but again I only blew a hose. Both JJ and Larry are spot on, situational mechanical advantages can apply forces that exceed design specs for strength. Sucks when it happens and something breaks but in my book, that's tractoring!