Metal hydraulic line keeps blowing

[Stone'd Mason]

32822-33412
This part has been replaced on my
L47 three times now. Can, or has anyone ever had a metal line custom made that is stronger ( thicker sidewall I’m assuming ) to replace a week oem part?
Where the bends are in the long 4 foot metal line is where I’m getting pin hole leaks. It’s a time consuming job to get to the line for replacement, not being a tractor mechanic the job took me two full days to replace last time. I even went to a shop that makes custom rubber hydraulic lines, the 2 wire flexible line they mocked up for me didn’t have the clearance to fit in the tight quarters where the metal line goes.

 

[GeoHorn]

Shouldn’t this be a WARRANTY Item?

 

[Russell King]

If you want a stronger line you will be able to get one at a Swagelok store (or similar). There are ZERO Swagelok stores so you may have to go to a reputable hydraulic shop.

Take one of the busted lines with you and they should be able to bend a hardline of greater pressure capacity and install the same type of ends on it.

But that line should be good for the rated tractor pressure so I think you might be creating too much pressure somehow or the line is getting damaged or rusting.

Good luck!

 

[Runs With Scissors]

Thats crazy.

I have never seen a metal line burst/leak solely from an "over-pressure” condition….especially twice.

I’m not saying that it can’t happen, but I would be looking at some sort of “other” cause.

Is the line being subjected to unusual vibration, or motion that is causing it to perhaps develop a small crack from “work hardening”?

Was the leak in the “same spot” both times?

Got pics?

 

[chim]

......................Is the line being subjected to unusual vibration, or motion that is causing it to perhaps develop a small crack from “work hardening”?

Was the leak in the “same spot” both times?.............................Got pics?

I'm thinking that's a contributor as well. Is there any reason the hose couldn't maybe take a slightly different route so it would fit? Not on a tractor, but I've seen tubing fail at bends. I thought it was due to the place in the line that absorbs the movement, plus the metal gets stressed somewhat during the bending process.
I remember reading a paper on corrosion being more of a problem at bends on steel pipe due to the stresses.

 

[TheOldHokie]

32822-33412
This part has been replaced on my
L47 three times now. Can, or has anyone ever had a metal line custom made that is stronger ( thicker sidewall I’m assuming ) to replace a week oem part?
Where the bends are in the long 4 foot metal line is where I’m getting pin hole leaks. It’s a time consuming job to get to the line for replacement, not being a tractor mechanic the job took me two full days to replace last time. I even went to a shop that makes custom rubber hydraulic lines, the 2 wire flexible line they mocked up for me didn’t have the clearance to fit in the tight quarters where the metal line goes.

That is the pressure supply line from the main hydrsulic pump and is unZIque to the L47. Three failures seems incredibly high for a machine thats only been in production for 9 years. What does Kubota say about it?

Dan

 

[PoTreeBoy]

Sounds to me like Kubota made or received a faulty batch of parts, but pursuing that would probably be more trouble than it's worth.

If possible, I'd have the leak welded up. And, if you have the line off, have it heat treated to stress relieve it. At least one person on here has reported successfully welding a line leak, but I don't recall it being an L47.

 

[TheOldHokie]

Sounds to me like Kubota made or received a faulty batch of parts, but pursuing that would probably be more trouble than it's worth.

If possible, I'd have the leak welded up. And, if you have the line off, have it heat treated to stress relieve it. At least one person on here has reported successfully welding a line leak, but I don't recall it being an L47.

I would like to know the length of time between each failure.

Dan

 

[SAR Tracker]

Being a welder in the USN years ago, I silver brazed quite a few hydraulic lines. Key is to clean them of ALL oil.

 

[mikester]

That is the pressure supply line from the main hydrsulic pump and is unZIque to the L47. Three failures seems incredibly high for a machine thats only been in production for 9 years. What does Kubota say about it?

Dan

I had to replace mine after it split on the welded pipe seam at the outer 90 degree bend located under the seat. You couldn't see or feel the failure point on the part. Under load oil would spray out like water from a 40 degree pressure washer nozzle.

I figure mine failed on my 10 year old machine because I was overloading my machine too much doing an armour-stone retaining wall using 2 ton blocks and my forks.

My observation is that K builds their equipment lightweight with minimal factor-of-safety on all components.

I asked the dealer about these part failures and he said they typically see them fail at the banjo fitting on the motor side.

I'd suspect the OP expects too much from his little TLB and or needs to check his safety relief valve. If you shock load your hydraulics you will see 10,000 psi pressure spikes on a line designed to handle 3,000 psi. Welded hydraulic pipe on my other construction equipment tends to be much heavier design than what K uses.

 

[Stone'd Mason]

I would like to know the length of time between each failure.

Dan

I’ve had between 5-7 pin hole leaks since I bought the tractor. I bought it brand new 7-8 years ago. I’ve had success welding it myself, sometimes I can get to the pinhole to weld it, other times the line has had to come off to weld. I bought a new line last year, took me way to long to get it installed, so I’ve been cautious to not work my machine as hard, but again another pin hole opened up and I welded it in the spring, now another one opened up and I can’t get to the location of the leak to weld. I’m very frustrated!!!

 

[TheOldHokie]

I’ve had between 5-7 pin hole leaks since I bought the tractor. I bought it brand new 7-8 years ago. I’ve had success welding it myself, sometimes I can get to the pinhole to weld it, other times the line has had to come off to weld. I bought a new line last year, took me way to long to get it installed, so I’ve been cautious to not work my machine as hard, but again another pin hole opened up and I welded it in the spring, now another one opened up and I can’t get to the location of the leak to weld. I’m very frustrated!!!

This does not strike me as being related to "working things too hard". I would say there is a ptonlem with the pipe or mounting. With that many failures I would be bypassing it with some good hose.

Dan

 

[PoTreeBoy]

I’ve had between 5-7 pin hole leaks since I bought the tractor. I bought it brand new 7-8 years ago. I’ve had success welding it myself, sometimes I can get to the pinhole to weld it, other times the line has had to come off to weld. I bought a new line last year, took me way to long to get it installed, so I’ve been cautious to not work my machine as hard, but again another pin hole opened up and I welded it in the spring, now another one opened up and I can’t get to the location of the leak to weld. I’m very frustrated!!!

I didn't know you had all those pinholes. Sounds to me like faulty tubing or pitting corrosion from salt, manure, or similar.

I think you said you couldn't get hose through some areas. Maybe you could run tubing through those areas and hose on the ends. Maybe shrink tubing over the tube to protect it in case there is external corrosion.

 

[McMXi]

32822-33412
This part has been replaced on my
L47 three times now. Can, or has anyone ever had a metal line custom made that is stronger ( thicker sidewall I’m assuming ) to replace a week oem part?
Where the bends are in the long 4 foot metal line is where I’m getting pin hole leaks. It’s a time consuming job to get to the line for replacement, not being a tractor mechanic the job took me two full days to replace last time. I even went to a shop that makes custom rubber hydraulic lines, the 2 wire flexible line they mocked up for me didn’t have the clearance to fit in the tight quarters where the metal line goes.

Can you tell if the pinholes are developing inside out or outside in?

I'm wondering if cavitation erosion is an issue with sudden loss of pressure resulting in the formation of micro bubbles which then collapse. The hydraulic line would resonate or vibrate at some frequency which would generate alternating high and low pressure regions inside the line. Bends could result in flow stagnation or vortices which wouldn't help. Just throwing it out there.