brazing a hydraulic line

[coloradotrout]

Thoughts on these?

 

[rScotty]

I like the Harris products, so I'd go with the bare wire Harris Safety Silv 45% that Amazon sells....and many welding shops sell Harris products as well. You will also need flux. Harris also makes a specific white flux for use with their safety silv wire.

Silver brazing is an art, but you can learn it. All the hints so far in this thread are good. You can do this...

It's just a matter of clean metal, not too much heat, use good products (Harris), and get it hot enough to flow but never so hot that the metal is scorched (forms an oxide coating). If it gets too hot just scape it clean and start over. The flux itself is painted onto the cold clean joint and can sit that way for a long time while you get everything set up. Then when you add heat, you will see that the flux will melt and flow a clear coating like frothy liquid glass. That tells you that the metal temperature is almost hot enough to add the silver wire. Sometimes I put tiny cut off pieces of the silver wire right in the flux on the joint. If they stay in position as the flux bubbles, they often become the very best indication of when to add more wire. Sometimes the little pieces are enough by themselves.

so watch your flux, the flux tells you when to add the wire. As the flux flows it cleans and coats the hot metal to protect the hot metal from forming an oxide. If the joint gets too hot, the flux will fail, all the colors will change as oxides form, and nothing will stick. Clean it all and try again,

Hot enough...but not too hot. Heat and clean metal are the secrets.
rScotty

 

[etpm]

When silver soldering/brazing the key to successful soldering is to heat the metal fast and let the metal melt the solder. The purpose of the flux it to clean the metal and keep oxygen away from the area to be soldered. Oxygen is kept away by the flux absorbing the oxygen. If the flux is kept hot too long it will absorb all the oxygen it can and then oxygen will get to the hot metal and oxidize it. Then the only fix is to remove ALL the burned flux and then sand or file the metal to remove all the oxides. If the metal is heated too slowly then the flux will be burned. So heat fast, don't heat the solder with the torch, don't let the torch flame touch the solder, and let the metal melt the solder. Just like when soldering copper pipe with plumbing solder.
Eric

 

[CATRAT66]

Did you simply replace the $1.00 O-ring?
That’s what actually makes the seal of those parts.

 

[CATRAT66]

If there is an actual crack or hole in the steel line you can measure the outside diameter of the steel tubing and go to the hydraulic supply guys and get a short piece with the correct end you need and a compression coupler
Very inexpensive parts

 

[coloradotrout]

If there is an actual crack or hole in the steel line you can measure the outside diameter of the steel tubing and go to the hydraulic supply guys and get a short piece with the correct end you need and a compression coupler
Very inexpensive parts

Idea noted!

 

[coloradotrout]

Did you simply replace the $1.00 O-ring?
That’s what actually makes the seal of those parts.

I know, right. I did that. Even looked at that again last year, and didn't see that to be the issue. I think it's a hairline/pinhole right near the factor braze from the line to the fitting. Pictures forthcoming.

 

[rScotty]

I know, right. I did that. Even looked at that again last year, and didn't see that to be the issue. I think it's a hairline/pinhole right near the factor braze from the line to the fitting. Pictures forthcoming.

Another way to fix it is to replace the steel line with a custom hydraulic hose, or a standard hose with end fitting adapters.
Then you can remove the existing tubing, have full use of the tractor, and repair the tubing more conveniently on a work bench.
rScotty

 

[bowenskye]

I've brazed a few different hydraulic lines, on old bulldozers / excavators / tractors. But the working pressure was always near, or below 2500psi.
I've also welded different hydraulic fittings together to adapt what I need to work with what i have.

 

[coloradotrout]

You can see the jb weld. The leak is there.

 

[coloradotrout]

Lower line disconnected. I used compressed air to clear the line of most fluid. The other end is attached to the tractor. I think I can get a torch and brazing rod in position.

Is mapp gas hot enough?

The leak is tiny and somewhere around the perimeter of the line to fitting connection. I watched for minutes and couldn't exactly pinpoint. At just idle it produces a drip once a minute or so. Under load - using the FEL, for example, it leaks much more.

 

[TMGT]

It needs to be clean, you'll have to clean out the inside with solvent and keep oil from getting to the joint. Otherwise it can wick the oil up into the joint and could male things worse.

Once cleaned inside and out with solvent (brake clean, acetone) heat it with the torch to cook any remaining junk out.

Sent from my SM-S921U using TractorByNet mobile app

 

[coloradotrout]

It needs to be clean, you'll have to clean out the inside with solvent and keep oil from getting to the joint. Otherwise it can wick the oil up into the joint and could male things worse.

Once cleaned inside and out with solvent (brake clean, acetone) heat it with the torch to cook any remaining junk out.

Sent from my SM-S921U using TractorByNet mobile app

I should be able to clean up the fitting and an inch or so in the line. Have to get at it from the fitting. Spray some carb cleaner or work a pipe cleaner in there. I don't want to heavily contaminate the fluid that is further down the line.

 

[etpm]

The problem you face with heat is not that MAPP gas is not hot enough, the problem is if you can heat the joint up fast enough. You have a big steel puck to heat up. You need to get it hot fast. A small but hot flame isn't going to be enough. You could use a weed burner to heat
the puck up fast and then go in with the MAPP torch to do the brazing. I suggest you practice on a similar sized piece of steel first to get your technique perfected. Or just go ahead and prove me wrong by just trying your MAPP torch on the joint and being successful. Let us all know how you do.
Eric

 

[coloradotrout]

The problem you face with heat is not that MAPP gas is not hot enough, the problem is if you can heat the joint up fast enough. You have a big steel puck to heat up. You need to get it hot fast. A small but hot flame isn't going to be enough. You could use a weed burner to heat
the puck up fast and then go in with the MAPP torch to do the brazing. I suggest you practice on a similar sized piece of steel first to get your technique perfected. Or just go ahead and prove me wrong by just trying your MAPP torch on the joint and being successful. Let us all know how you do.
Eric

The puck is about 2" in diameter and hollowed out for the fluid and 3 bolt holes. I need to settle on which brazing rod to buy. The lowest temperature that will hold is what I'm thinking!

 

[etpm]

The puck is about 2" in diameter and hollowed out for the fluid and 3 bolt holes. I need to settle on which brazing rod to buy. The lowest temperature that will hold is what I'm thinking!

Good luck.
Eric

 

[jwmorris]

This is a brazed joint.

If it is leaking at the joint between the puck and line, you will indeed need good luck, just "going over it".

You will need to heat and separate the two to properly prepare the two surfaces for a successful bond.

We all already know there is oil between the two now, that will ruin any chance of seal once heated, or you wouldn't have found that spot to be the source of the leak.

 

[coloradotrout]

This is a brazed joint.

View attachment 4419919

If it is leaking at the joint between the puck and line, you will indeed need good luck, just "going over it".

You will need to heat and separate the two to properly prepare the two surfaces for a successful bond.

We all already know there is oil between the two now, that will ruin any chance of seal once heated, or you wouldn't have found that spot to be the source of the leak.

Thanks. I can try compressed air all around that area and some carb cleaner with compressed air to see if I can get it clean. The leak is tiny. At idle I get a drop every minute. Under load it's a drop every 10 seconds. The scratches you see in that photo are from a knife to get my JB weld off. The JB was tight against the line, but not so much near the puck. That suggests to me that the leak is right at that joint. Plan B is to clean it up, and lather on another JB weld. I guess plan C would be to replace this with a hose. I have another puck from another engine and that was has a screw on fitting.

 

[jwmorris]

The JB weld would probably have a better shot if you intend to leave the joint together. If you can keep it from vibrating around it might last longer.

The oil in the joint, likely won't come out until you begin to heat, then it will keep wicking out and ruining any chance of a good seal. Why it needs to come apart to he cleaned.

 

[coloradotrout]

Bought these. Will test on scrap. Doubt my mapp gas only torch will melt.