Catastrophic Failure

[3v0]

How many hours are on the L2900GST ?

 

[Coyote machine]

To the OP: does anything come to mind that could explain why the problem occurred, that might go back some time beyond recent use, where the tractor was being strained in any way?
Anything having to do with use of the 3PH or any heavy load condition that could have led to the failure over time?

Who is Carl?
And forget about buying American- there's virtually nothing made here anymore, and what if there were...nothing made in America has ever broken?

 

[Don87]

To the OP: does anything come to mind that could explain why the problem occurred, that might go back some time beyond recent use, where the tractor was being strained in any way?
Anything having to do with use of the 3PH or any heavy load condition that could have led to the failure over time?

Who is Carl? And forget about buying American- there's virtually nothing made here anymore, and what if there were...nothing made in America has ever broken?

http://www.tractorbynet.com/forums/...ting/269143-smaller-john-deere-out-pulls.html

 

[PitbullMidwest]

How many hours are on the L2900GST ?

1400+

 

[PitbullMidwest]

To the OP: does anything come to mind that could explain why the problem occurred, that might go back some time beyond recent use, where the tractor was being strained in any way?
Anything having to do with use of the 3PH or any heavy load condition that could have led to the failure over time?

Nothing comes to mind, I drag a 5' box or 5' grade blade behind it and brush cut but nothing outside normal or intended 3pt use. But the cylinder assembly controls all things hydraulic, so repeated use of the FEL to push, lift and compact (down pressure) the burn pile may have lead to a failure over time, but again nothing outside of what I would say is normal, intended use of a FEL. I will say though that every time I've ever exceded the load limit the bypass relief valve has kicked in.

 

[Don87]

Nothing comes to mind, I drag a 5' box or 5' grade blade behind it and brush cut but nothing outside normal or intended 3pt use. But the cylinder assembly controls all things hydraulic, so repeated use of the FEL to push, lift and compact (down pressure) the burn pile may have lead to a failure over time, but again nothing outside of what I would say is normal, intended use of a FEL. I will say though that every time I've ever exceded the load limit the bypass relief valve has kicked in.

Everything is pointing to the relief valve.

 

[brain55]

Everything is pointing to the relief valve.

Just to be clear, not the system relief but the safety relief. You had said it was 4 degrees out I believe, the oil in the 3-pt is static if you aren't using it. If the 3-pt was raised all of the way up there is only so much thermal expansion that can happen in the cylinder before the mechanism bottoms out. Once that happens if enough thermal expansion happens and the safety relief doesn't let out that pressure build up stuff breaks. I'm only guessing without seeing pictures and I probably wouldn't have come to this conclusion if he hadn't mentioned they were pushing stuff into the burn pile. I'm thinking there was enough temperature swing in the static cylinder to cause the problem.

Brian

 

[DFB]

Im sure differnt manufactures use different setups but on my system there is only the one rockshaft mounted system pressure relief valve to control ALL hydraulic system pressure from the loader 3point, and my aux pb circuit. It consist of a valve seat, needle valve, spring assembly and is adjusted by a threaded screw pressure on the spring follower. Internally the rockshaft control valve has several check ball spring that close off and open hydraulic flow to sump when the rockshaft lever is activated. Even if one of those circuits failed the system relief would be there unless the spring failed or the needle got stuck somehow and wouldnt lift I've often heard of reliefs being held open usually by a floating chip of metal in the system fluid but never the opposite. Not that it couldnt happen I guess. I hope the hyd pump didnt get damaged.

 

[brain55]

Once the 3-pt cylinder has lifted the rockshaft to the desired position the control valve shuts off the flow of oil to the cylinder. The hydraulic pump and the relief valve are no longer involved. The only way fluid is let out of the cylinder at that point is by moving the control lever or by internal leakage. If the control linkage is properly adjusted, and you raise the control lever to the full up position, you should manually still be able to lift the lift arms a couple more inches, this gives you room for the thermal expansion. If the linkage is not properly adjust or somebody adjusts it to get that last little bit of implement lift you don't have room for that expansion. It is possible too that there is no safety relief on that machine and they rely on proper linkage adjustment.

Brian

 

[DFB]

Right. Op said they started the tractor. So the scenario on my machine would be the pump would be pumping and with nothing moving (rockshaft or loader) the oil should just be being relieved to sump by the rockshaft control valve check ball and if that didnt happen the system relief should lift and if it didnt kaboom.