Catastrophic Failure

[PitbullMidwest]

My son and brother in law were cutting and burning trees last week and were using my L2900GST to push the trees into the burning pile. All was well until they heard a load "bang" and the 3ph dropped and oil began gushing from under the seat .

By the time I got home from work they had the front access plate off and it didn't look good. My BIL got his JD3020 and we pulled my tractor up to his machine shed (every JD owners dream)and we pulled the operator station. Long story short, the hydraulic cylinder assembly housing had cracked from one side to the other. Priced new it's a $700 part plus labor and transport. We're going to remove it ourselves to save some money and see if it can be welded.

My dealer says he's never seen this happen before and asked what they were doing at the time of failure. That's whats odd, they weren't "doing" anything. They had been working the tractor all day without any problems. Transmission wasn't slipping, the loader was responsive, everything was "normal" so as far as we know the hydraulic oil level was good. They said they had taken a break and came back and started the tractor and hadn't even put it in gear when "bang' and oil started gushing.

Before anyone suggests that my BIL was abusing the tractor, let me just say that he treats it better than I do and I don't abuse it because I don't like $700 repairs.

Anyway, all theories as to what may have caused the failure will be entertained.

 

[Tomtint]

I bet a JD owner was jealous and sabotaged it when no one was looking !

 

[Leejohn]

Can you get a picture of it?

 

[PitbullMidwest]

Can you get a picture of it?

Sure, we hope to able to pull it this weekend. His shop is unheated and it's 4 degrees today and high tomorrow is only in the teens. The spirit is willing but...

 

[DFB]

Were they pushing with the 3 point?

 

[brain55]

My son and brother in law were cutting and burning trees last week and were using my L2900GST to push the trees into the burning pile. All was well until they heard a load "bang" and the 3ph dropped and oil began gushing from under the seat .

By the time I got home from work they had the front access plate off and it didn't look good. My BIL got his JD3020 and we pulled my tractor up to his machine shed (every JD owners dream)and we pulled the operator station. Long story short, the hydraulic cylinder assembly housing had cracked from one side to the other. Priced new it's a $700 part plus labor and transport. We're going to remove it ourselves to save some money and see if it can be welded.

My dealer says he's never seen this happen before and asked what they were doing at the time of failure. That's whats odd, they weren't "doing" anything. They had been working the tractor all day without any problems. Transmission wasn't slipping, the loader was responsive, everything was "normal" so as far as we know the hydraulic oil level was good. They said they had taken a break and came back and started the tractor and hadn't even put it in gear when "bang' and oil started gushing.

Before anyone suggests that my BIL was abusing the tractor, let me just say that he treats it better than I do and I don't abuse it because I don't like $700 repairs.

Anyway, all theories as to what may have caused the failure will be entertained.

Here is my shoot from the hip response since nobody has offered anything other than ill informed green vs orange silliness. The safety valve for the 3-pt failed. It is supposed to relieve excess pressure in the 3-pt cylinder when it is overloaded or as I suspect the oil in the cylinder got too hot and had no place to expand so it broke stuff instead.

Brian

 

[PitbullMidwest]

Were they pushing with the 3 point?

Nope,just the bucket

 

[Don87]

I bet a JD owner was jealous and sabotaged it when no one was looking !

Anybody seen Carl?



All joking aside, I agree with the relief valve.

 

[DFB]

Nope,just the bucket

Then I also believe a failed relief valve

The reason I asked is by pushing brush and logs piles high with a raised blade on the back you could easlly do something like breaking the rockshaft housing by jamming the lower lift arm links backwards and up into the rocker shaft arms

 

[robbyr]

Anybody seen Carl?



Ha ha too funny, he's over on page 30.:laughing:

 

[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.