fried1765
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"stop drilling" is widely used in the aviation community.
Cracked or pinhole leak in hydraulic steel tube
- Thread starter DaveK OR
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"stop drilling" is widely used in the aviation community.
rScotty
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I've heard that. But as good a technique as stop drilling is, it still isn't popular. There just can't be a simpler & cheaper way to stop a crack from spreading. The theory and math of why it works is so instructive that it is taught in every materials course.
BTW, backfilling the drill hole is just done for appearance. It's the hole that does the good.
TractorGuy
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Like others have said. Welding or brazing or replacing with a hose are all okay alternatives.
I mig welded a tube on one of my backhoe stabilizers that hasn't leaked again in 2+ years use. I also replaced one of the crowd cylinder hard lines with a hose. Both fixes are working fine.
I mig welded a tube on one of my backhoe stabilizers that hasn't leaked again in 2+ years use. I also replaced one of the crowd cylinder hard lines with a hose. Both fixes are working fine.
My thanks to all the helpful replies. I've been dealing with other, more urgent issues for the past few weeks, so didn't have time to make progress on the repair, or to respond to the helpful posts.
I was able to contact the Bobcat dealer in Portland, OR, and they were able to order a replacement hard-line for an exact fit. Not cheap, but not what I consider outrageous for specialty parts.
After removing the old line, I was finally able to locate the teensy little crack, which is in a fillet weld at the double-O-ring connector to the joystick valve assembly. It was not the best design, but the replacement part has sleeves that the hard line slips into and is either brazed or welded in place... much stronger connection. I'm betting that Bobcat or Kioti ran into this problem before, hence the improved design of the hard-line terminations.
The fun part was getting to the line for removal and replacement. Not only did I have to remove the FEL (easy), I also had to pull the right FEL attachment bracket off (not quite so easy). Since I have a Woods Backhoe subframe, also attached to the FEL brackets, it was even more interesting.
Anyway, the old cracked line is out and the replacement is solidly in place. Just have to get the FEL bracket back on and bolt everything up tight and I'll be back in business.
I was able to contact the Bobcat dealer in Portland, OR, and they were able to order a replacement hard-line for an exact fit. Not cheap, but not what I consider outrageous for specialty parts.
After removing the old line, I was finally able to locate the teensy little crack, which is in a fillet weld at the double-O-ring connector to the joystick valve assembly. It was not the best design, but the replacement part has sleeves that the hard line slips into and is either brazed or welded in place... much stronger connection. I'm betting that Bobcat or Kioti ran into this problem before, hence the improved design of the hard-line terminations.
The fun part was getting to the line for removal and replacement. Not only did I have to remove the FEL (easy), I also had to pull the right FEL attachment bracket off (not quite so easy). Since I have a Woods Backhoe subframe, also attached to the FEL brackets, it was even more interesting.
Anyway, the old cracked line is out and the replacement is solidly in place. Just have to get the FEL bracket back on and bolt everything up tight and I'll be back in business.
PILOON
Super Star Member
Here I agree.
I once studied the PSI strength of brazing vs rod (TIG/MIG) welds and was quite surprised as to the strength.
Naturally you want to re treat to harden properly.
Yes, while weld joints have very high tensile strength, they also can end up being very brittle, and I suspect that is a major factor in the failure that I experienced. A brazed connection, while likely having somewhat lower tensile strength, can be more forgiving in a joint that is subjected to flexing loads.
I'm happy that I could source a replacement part from Bobcat, since the location of the crack would have made a proper brazing job a bit difficult. If the line had worn through or cracked in the middle, many other repair options would have been possible. Still, being able to obtain an exact replacement part was the best option for me, since having a new connection set built to use a flex-line would likely have cost just as much and taken more time.
I'm happy that I could source a replacement part from Bobcat, since the location of the crack would have made a proper brazing job a bit difficult. If the line had worn through or cracked in the middle, many other repair options would have been possible. Still, being able to obtain an exact replacement part was the best option for me, since having a new connection set built to use a flex-line would likely have cost just as much and taken more time.
MH8675309
Platinum Member
I silver soldered many stainless hydraulic lines into stainless junction blocks. The directions work well for regular steel too. Im sure glad you caught that
rScotty
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RIght. I'm also a believer in silver solder - i.e. silver brazing - for lots of connections. Especially for stainless tube into a fitting or block. There is no requirement for heat treating a silver brazed joint.
rScotty