Can you braze a hydraulic line?

[DieselBound]

Can't wait to break something so I can test this out!

 

[ROUSTABOUT]

Before there was duct tape, there were steel coat hangers. The original multi-purpose DIY that was always close at hand.
My wife has replaced all of the house coat hangers with plastic, But I kept a dozen or so in the garage because sometimes that is all you need is a little piece of coat hanger to do a task where nothing else seems to work.

In the middle of nowhere Oklahoma I helped a man fix his truck. I found another truck. We cut the bent frame off his and cut the straight part off the other. Welded truck together with brown clothes hangers and a torch. Right there in the pasture.

 

[Smokeydog]

Joint fit is critical for proper brazing joint strength. Metal cutting bandsaw blades can be brazed together and last the life of the blade. Tough test for any joint. Properly done the bonding strength exceeds the mechanical properties of the filler metal. Depending on the crack size, deformation, patch fit or tightly wrapped wire adds to bonding strength. The OP’s successful repair is just the small amount of material bonding at the split edges not a large puddle on top. Having experience brazing helped the OP too.

Long ago demo a well used, farm grade Ford 3500 backhoe. Strong machine that obviously had the hydraulic pressure turned up. Almost every hard line at bends had rough brazed repairs on the loader. Didn’t buy that one but the hook had been set.

Monitor hydraulic line pressure on the loader of my M59 with a gauge installed with a soft ride system. Max pressure slightly below of range spec. Thought about increasing the pressure relief but the machine is already scary strong. With OP experience feel better about leaving the relief pressure on the low side.

 

[CADplans]

You got your PHD in brazing. Looks good. Is it an injury risk if it fails?

Does that PHD stand for Piled Higher and Deeper filler metal??

That is what my PHD would stand for,,,

 

[jaxs]

I've got to remember that trick, too. It's a good one.
The resulting composite of steel and silver stands a decent chance of being better than either alone. I'd love to see some formal testing.
rScotty

Can't wait to break something so I can test this out!

Y'all should get togeather and tear something up then try to fix it.

 

[CJONE]

Been in the hydraulic business for over 25 years. Alot of the fittings you buy are 2 piece brazed fittings. I have field repairs that have been holding at up to 6000psi for years now on fittings and many lines that were mig or gas welded. I quit brazing them 30 years ago when I learned to weld. Braze will hold on a fitted joint but not normally a hole or Crack unless there is enough build of the filler and it is relatively low pressure. If the line is basically empty the heat will eliminate any oil residue. Compression fittings are good through 5000psi and 2 piece ferrules will hold stainless steel lines well beyond the line pressure ratings. Cj

 

[CADplans]

The Navy taught me to braze (and weld) in 1971,,
After practicing, we were given an assembly of several size pipes, and plates that resulted in a container with a 3/4" NPT pipe.
The pipe could be mounted in the booth at any position, but, not moved after we started.
We oxy-acetylene welded one, then oxy-acetylene brazed the other.

Then, they screwed the assembly to a pump that put water in the assembly, and recorded pressure.
Several of us in the class brazed and welded both assemblies to be able to make it to the max pressure of 3,500 psi.

The instructor was surprised, usually only one guy maximum in the class could get both to max pressure,,

We also silver brazed Inconel pipe to some fitting that had an included silver solder ring,
That was kind of easy, if you were willing to take the time to clean the parts perfectly.

And we brazed cast iron bars, about 1/2" thick, the bars formed a simple butt joint.
The finished assembly was put in a press,
the braze had to hold, and the cast iron bar had to break next to the braze joint.

I think they were only trying to teach us that a braze joint could be incredibly strong,,

 

[CalG]

Just because

When making a repair to a pressure line, (I have no issues with a brazed patch, cleanliness! Clean! and clean again, brake cleaner is your friend!) be aware that a pinhole can allow a spurt of oil that can cut through flesh like a hot knife through butter.

Wrap the "wound" with paper towels or shop rags when doing the after repair proof testing.

Don't ask me why I'm writing this.

 

[CADplans]

Just because
Wrap the "wound" with paper towels or shop rags when doing the after repair proof testing.

Don't ask me why I'm writing this.

It did not happen,,, without pics,,, of the bandages,,,

 

[metalbender]

Yup on the PHD when it comes to filler. When a politician uses the term it's reference is to BS.

 

[m1garand762]

I have a split steel hydraulic line on my Kubota M59. I ordered and have the replacement line. After two days disassembling my tractor, I have realized it is impossible to remove and replace the line. It was apperantly installed early in the construction of the tractor and never intended to be replaced. Which would have been fine if the materials had been higher quality. It was not damaged, it failed. So now I'm thinking I will have to cut the old one out and have a flexible line built on to the Kubota ends. That got me thinking they might have to braze hose fittings onto my cut tubes. So can I braze over the material defect in my tube?? I braze copper lines regularly and brass and steel fittings occasionally. I usually use a 45-55* silver braze with flux on steel or dissimilar metals. Sometimes I will cap with a 15* silver just to beef it up. Any reason I can't do this on a steel hydraulic line??

Blow the line out good if you can get to both ends. Flush some detergent through blow it out with air to get the residue out. Use your 55% with flux and flow nitrogen while torching to keep the inside of the line clean

 

[jwmorris]

I have TIG welded special ends to new hose/crimp ends lots of times over the years. I would imagine silicon bronze filler would work just fine but I always used ER70s.