BL4690 Bent cylinders

[MAG]

This is the second cylinder I have bent on this BH. First time I thought I did something wrong. This time I was finishing up a 200' trench and I heard a screach, cylinder shaft bent! What gives? I was just digging away doing nothing weird. I'm thinking of a stronger cylinder?

 

[ronjhall]

Has the hydraulic pressure for system been checked. I have watched that cylinder on my BH closely. Have never seen it flex yet.

 

[art]

Last time I saw one bent like that the fellow was wondering what was holding the tractor back when he was pulling ahead and he didn't have the boom up high enough.

 

[JerryG]

Were you digging up close to the tractor?

 

[Wayne County Hose]

Something pushed the rod back into the cylinder. I know you think you did nothing wrong, but rods don't just bend.

 

[Ob1kubota]

This is the second cylinder I have bent on this BH. First time I thought I did something wrong. This time I was finishing up a 200' trench and I heard a screach, cylinder shaft bent! What gives? I was just digging away doing nothing weird. I'm thinking of a stronger cylinder?

Question the OEM for a print of the boom design and measure the ratio of extension to retraction of main boom to the bucket stick. Your Photo suggest the mechanics of the ram piston ( rod ) is extending beyond the internal relief of the barrel. Have a hydraulic shop use a cylinder press to pull the damaged rod out of the barrel to confirm the evidence. I suspect the cylinder extension capacity is beyond the mechanical advantage of the boom stop weldment on the curling action of the bucket stick. If the original cylinder failed in this exact configuration the load inertia moment has shifted from the intended design of the manufacturer for mechanical advantage of breakout force considering the hydraulic circuit relief is correctly set. Go figure...200' into a ditch, everything expanded by heat of the working load and you are curling back to clean the bottom and this **** happens...

 

[MAG]

I was finishing the trench and reaching in close and down. This extends the dipper cylinder all the way. When I curl the bucket to take a scoop this puts pressure on the fully extended dipper cylinder and it bends. If it is not supposed to operate in this position then why can it be put in such a position? Or why not a warning not to operate close to the tractor?

 

[mazurrj]

I bent two that same way digging up close ith dipper all the way out. After the second time i learned not to do that. Differnet model than your'es and not saying you will bend it all the time that way but you are closer to the limites of the cylinder when digging in that posistion is all i can figure. some say they never had problem digging up close and do not know why it does not happen to everyone? Its been two years now with no problems for me, long as i make sure i'm digging nothing tough up close and move the tractor away and keep from digging up close no problems. There may be more too it with you'res, just telling you my experiance which i've posted on the form many times. Just when i saw you'res , same place rod bent on mine. You're looked worse than mine and i think is bent the opposite of both mine.

 

[MAG]

I just called my Kubota dealer $393.00 for the "Cylinder Crowd BL469". That is better than my last rebuild price, pleasantly surprised with Zubota's price. Also this is the first time I've seen the term cylinder "crowd", any one familiar with that term? I'll try and keep from digging close and deep. Thanks.

 

[Wayne County Hose]

That's a good price for the whole cylinder. Keep the old one for parts. I would also price out the rod and seal kit separately.

Crowd cylinder is a common name for that particular one. I don't know how it got it's name, but I have heard many manufacturers refer to it as that.