steal line rupture

[Egon]

txdon;

With the comments many others have made I'd suggest talking to dealer and thinking about some line replacement. For sure the one that was brazed.

Egon

 

[Youare]

At 6000 psi it is a good thing there is a shield over that line where it broke. You could have gotten a good shot of oil in the face.

I would be thinking of repalcing all the steel lines if there is any chance they all my have the same weakness at the seems

Randy

 

[JimR]

The picture is decieving. The line just looks pitted in the picture.

 

[txdon]

<font color="blue"> "...pushing forward with the bucket down will add many thousands of pounds of pressure to the hydraulic system." - RaT</font>

It seem that Rat might have come up with the best explanation of why the line broke. I don't know for sure but the ingredients seem to have been there. I was moving forward and alternating between tilting and lifting. My dealer informed me that the relief valve does not operate when the valve is in the neutral position. RaT has measured the PSI increase to 6,000 pounds. I cannot rule this out. I called a large Houston Kubota/New Holland Dealer and they have sold a lot of loaders like mine and the service manager reported only having replaced one steel line - and that was on a three year old New Holland loader. My dealer checked his parts usage list and only one line with the part number of my line was replaced.

Like RaT the Houston Dealer also remembered several years ago a recall of some hydraulic hoses but no steel lines.

I guess a truly accurate study would include all loaders on the grand Ls and all four part numbers (each line). However I have not seen this problem here on TBN so I feel OK about the integrity of the lines. But I'm still not standing in a raised bucket.

Egon, my dealer is sending me a new line free. I have good dealer support! /forums/images/graemlins/smile.gif

 

[Egon]

Good show Don. /forums/images/graemlins/grin.gif

Egon

 

[dlgmt]

My L3130 w/723 loader did the exact same thing this past July, it sounded like a 22 cal. rifle when the line split. I am thankful that guard was in place. I removed the line and took it to the dealer he agreed that it looked like it split on the seam, he ordered a new one and covered it under warranty being the tractor/loader was only four months old at that time.

 

[txdon]

dlgmt, What were you doing with the FEL at the time? Were you also moving? Was the joystick in the neutral position for the line that broke?

I think I know what I did and I am operating the FEL differently now. I make sure the bucket tilt is engaged when I try to tilt up and drive forward. That is the only way the relief valve will work, otherwise the pressure put on the cylinders is trapped in the lines and continues to increase as I drive forward.

 

[dlgmt]

txdon, I had just installed my tooth bar that a.m. and was trying it out by moving and leveling some dirt around my pond. I did have the bucket tilted forward and was moving foward when the teeth on the bar caught a stump that was just below grade. I guess the spike in line pressure between the cylinders and the control valve caused the line to fail @ the weak point(seam).

 

[txdon]

dlgmt, I had my tooth bar on also and was under stubborn brush roots moving forward. It looks like the suspected diagnosis has been verified. Thanks, and thanks RaT for sharing your pressure measurements on the hydraulic line.

 

[billycalexander]

I own a Grand L 3430 about 2 years old now and the exact same thing happened to me . I'll have to look to remeber which line it was but it ruptured in the same area under the shield.

 

[txdon]

Billycalexander, thanks for sharing. I wonder if this also happens on other brands of tractors as well. Maybe there needs to be some kind of pressure relief valve when the joystick is in the neutral position.

 

[jinman]

</font><font color="blue" class="small">( Maybe there needs to be some kind of pressure relief valve when the joystick is in the neutral position. )</font>

A steel tubing rupture has happened to bgott in the NH forums and I have blown four hoses on my NH. Rupturing steel tubing is probably pretty rare. I'm just glad yours didn't let go when you were trying to lift Lucy.

I think the thing about a relief valve is it would need to be set pretty high, somewhere around 6000 to 8000 psi. As RaT noted earlier, his 5000 psi gage pegs easily on his tractor. I guess you could set your relief at 1-1/2 to 2 times the normal maximum pressure. What do you have in mind, Don?

 

[txdon]

<font color="blue"> "What do you have in mind" </font>

Jim I was thinking that maybe the valve could be redesigned so that when the pressure is put on the bucket by driving forward the pressure could be released even if the joystick was in the neutral position. I don't know what the negative ramifications would be, but it's got to be better than system failure.

Or, there could be an in-line 5,000 psi relief valve on each line that fits at the hose to steel connection.

 

[jinman]

</font><font color="blue" class="small">( Or, there could be an in-line 5,000 psi relief valve on each line that fits at the hose to steel connection. )</font>

Don, I believe the relief only needs to be in the bucket's curl-up side. When you are back dragging with the bucket, hitting an obstacle would most often just lift the front of the tractor. When going forward with the bucket curled down, I think you are most likely to find high pressure spikes from hitting roots, rocks, or stumps. (I have had two hydraulic showers from hitting stumps. /forums/images/graemlins/crazy.gif) If I had one pressure relief valve, I'd want it in the curl-up side.

I have been looking at hose for my grapple. I believe the 1/4", 5000 psi hose has a burst pressure up around 14,000 psi. Do you think we generate pressures anywhere near that high? Bailey has a 5000 psi pressure gage on sale right now for $8.95. I may just get one and set it up with quick connect fittings so I can install it inline with the loader.

I also checked to see if they have a relief valve that could be installed. The problem is they only have relief valves that go up to 3000 psi. A higher pressure relief valve may be a special order item and cost big $$$. The relief valves with 3/8" fittings are 1500 psi maximum. To get 3000 psi, you have to go up to 3/4" fittings. 1/2" fittings top out at 2500 psi. So we may be able to discuss this issue, but putting it into our systems could be an expensive plumbing nightmare. /forums/images/graemlins/frown.gif