Catastrophic Failure

   / Catastrophic Failure #52  
not sure on how the linkages operate in rear end....

just wondering if someone ran rear of tractor into something (going at a good speed and ran into a brick wall for example), causing pressure of linkage arms to go right through the cylinder....
or tried to toss a chain around a tree, and left enough slack in chain and took off fast for a "snap", that instead of chain or linkage arm damage, it caused casing to fatigue and/or crack.

once above was done to get a micro crack going....

thinking thermal expansion was final lick, that caused the final break down. more so if tractor was worked pretty good a few hours before hand, getting all the metal and hyd oil and entire tractor warm.

*rubs chin* normally after a good work out on tractor (running highest gear possible, highest RPM's possible) and really working the tractor, will just not turn off tractor and walk away, but will get RPM's down low to idle, and maybe even drive at a lower RPM if real worked transmission before hand. to let everything have a chance to cool down, via, radiator, hyd oil coolers. and let that coolant workout out those high temperature spots. then shut unit down after say 5 to 10 minutes after the cool down doings. just like regular exercising and keep your muscles from cramping up, you do a "cool down session" same like thing for tractor. to prevent them pin point hot spots from over heating different areas.

there be a reason why tractors have active coolant, (fans, radiators, hyd oil coolers) but once tractor gets shut down, that all goes away....
 
   / Catastrophic Failure
  • Thread Starter
#53  
Well, we pulled the housing last weekend and now I understand why it's a $700 part, I also have a better understanding of what goes on inside the housing. Since I don't know the proper names of the components, I'll use terms I think we can all understand. When the 3pt is raised oil is pumped into the reservoir behind a piston about 4" in diameter. In the face of the piston is a recess that a ball-end pushrod fits and the other end of the pushrod is connected to a crank attached to the lift arms. As oil is pumped into the reservoir the piston is pushed up the cylinder, pushing the pushrod, acting on the crank raising the 3pt. When the 3pt is lowered pressure is relieved in the reservoir and the piston retracts.

Only a small part if the housing is actually pressurized and naturally this is where it cracked. We didn't pull the piston since we didn't have a ring compresser to reinstall it but it slides smoothly through its entire travel. As has already been suggested, all things point to 1 of 2 possibilities: a. failed safety bypass or b. overlift of the 3pt from either pushing or backing into something.

My boy drives for UPS and when he delivered to the welding shop he told them what had happened and they said they had just welded a cast housing on an ag tractor so they were confident they could fix it but until they see it, who knows. My BIL is supposed to drop it off today.

I forgot the camera but took pics with my cell phone but can't figure out how to get them off the phone into the computer. Tried emailing them to myself but they show up as .mp3 attachments :confused:

Anyway, that's the latest news.
 
   / Catastrophic Failure #54  
That piston has an o-ring and back-up ring I would definitely replace those while I had it apart. You don't need a ring compressor.
 
   / Catastrophic Failure
  • Thread Starter
#55  
... You don't need a ring compressor.

Thanks Brian, good to know.

BTW, I want to publically thank Messicks for providing the interactive .pdfs, what a great resource!
 
   / Catastrophic Failure #56  
It doesn't work that way, all the descent rate valve controls is the rate of fall. It's a check valve of sorts and is spring loaded. It has no effect on the raise part of the cycle, even if it's closed completely

Sean: That's interesting. I need to go out and check, but I'm 99% sure my owner's manual says not to raise the 3-point with the descent control locked because it'll burn out the hydraulic motor. I assumed it was the equivalent of deadheading a valve with nothing attached to it.
 
   / Catastrophic Failure
  • Thread Starter
#57  
I was able to get one pic off of my phone for what it's worth, hoping to hear from the welder today... stay tuned


hydrauliccylinderremoved.jpg
 
   / Catastrophic Failure
  • Thread Starter
#59  
No, not sure what we'd be looking for if we did. The dealership offered to go through the control valve assembly to see if they could determine what might have caused the failure. Maybe I should have them look at the safety valve too.

Yikes! The control valve is $476 (the 2 bolts that hold it on are $8 each ) and the safety valve is another $105
 
   / Catastrophic Failure #60  
Well looking at the attachments it is a spring/check ball set up. It has to freely move to release hyd pressure. It has been suggested it might not have done that correctly
 
 
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