brazing a hydraulic line

coloradotrout · Oct 31, 2005

I have a small leak in the metal pressure hydraulic line right at the fitting. It leaks a couple of drops per minute. I was thinking maybe I could braze it shut. I cannot even see where it's leaking. At home depot they have 3 or 4 kinds of braze - bronze, nickel-silver, and a couple of others (aluminum maybe). A replacement part is $250.

RedRocker · Oct 31, 2005

Silver solder should do the trick. Brass would probably be fine too.

coloradotrout · Oct 31, 2005

Just regular old silver solder? the stuff used for copper pipes?

Just heat the joint up.. and apply the solder?

I suppose it best to sand off as much paint/corrosion as I can..

HomeBrew2 · Oct 31, 2005

I'm pretty sure Redrocker meant real silver solder. Typically you need less heat than brass which is nice for small/thin stuff. A welding supply should have it. If not a place that sells jewelry making supplies. It comes in several melting point temps. And it uses it's own kind of flux.

3RRL · Oct 31, 2005

I agree with RedRocker, silver solder will work just fine.
Be sure to prepare the area by removing as much paint and crud as you can around the area. Then apply the flux neatly and evenly. The flux application is key to a good job because it controls the flow of the solder. I use Harris "stay-silv" silver solder flux.

geneP · Oct 31, 2005

If you can't see where it is leaking, how are you going to solder it? Are you going to solder the nut/connector to the steel line? Maybe it is leaking at the seat, or o-ring if it has one, and removing the connection might reveal the source of the leak.

RoyJackson · Oct 31, 2005

"Just regular old silver solder? the stuff used for copper pipes?"

That's not silver solder...that's a lead/tin alloy used to sweat copper joints.

Real silver solder will require more heat...probably MAPP gas (at least).

You can give it a try, but I'm not sure any solder will work on a hydraulic system that pushes >2000 PSI. Of course, some aerospace hydraulic fitting are silver soldered...I know...I did some whilst in the Navy. But these joints were not pinhold leaks.
Can't hurt to give a try though!

VA_Joe · Oct 31, 2005

I agree - that is a lot of pressure for a soldered connection.

JerryG · Oct 31, 2005

I don't know what you have in your area, but you could take the old line to a hydraulic shop. We have one in the area that makes up metal lines as well as hoses. It would be a LOT less expensive than the dealer.

HomeBrew2 · Oct 31, 2005

You might want to read up on silver soldering, aka silver brazing ... it's pretty strong ... nothing like soft-solder. Also, around these parts, lead in solder, for potable water, has been outlawed for a long time ... kindof a safety issue. One compound for potable water pipe soldering uses tin, copper and selenium.
Cheers!

escavader · Oct 31, 2005

DONT DO WHAT I DID
I broke one of the nipples right off the hydro pump/tank on my old fisher plow.Igot a new end ,and arc welded it on.[i didnt have torches] It oozed just a little all last winter,until the last storm,when one of them little peices of slag fell out,during the last storm.NEEDLESS TO SAY I THE ENGIN COMPATRMENT OF THAT OLD FORD AINT GONNA RUST NO TIME SOON /forums/images/graemlins/blush.gif /forums/images/graemlins/blush.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif
ALAN

Soundguy · Nov 1, 2005

( You might want to read up on silver soldering, aka silver brazing ... it's pretty strong ... nothing like soft-solder )

Ditto.. Many double barrel shotguns are silver soldered between the barrels.

( , around these parts, lead in solder, for potable water, has been outlawed for a long time .. )

Also ditto..Around here, No lead in plumbing solder for over a decade.. probably twice that.

I have used propane torch and silver bearing solder to sweat pipes.. not as easy as old leak solder.. but it works. Mapp torch does it fine too.

Soundguy

RichNJKubota · Nov 1, 2005

I've used regular brazing and silver solder for repairing old rusted steel hydraulic lines. Done it for many many years and it always works.

Rich

Farwell · Nov 1, 2005

I worked for the Southern Pacific Rail Road when I was a kid and we used a product called Gold Floss to fasten hydraulic fittings together. It was similar to brazing but much stronger. The fittings were used on hydraulic motors that would drive very large fans at the rear of the locomotives.
I would think that real Silver Solder should work. The fittings do have to be very clean and accessible to get the best results.
Farwell

coloradotrout · Nov 7, 2005

Just to clarify.. I don't have a fitting to seal, just the connection from the probably 1/4" line to the connector that then bolts (w/ o-ring) to the hydraulic pump. Somewhere at the pt where the line is attached to the connector I have a 2-3 drop per minute leak. I was just hoping to heat up the whole area and lay some solder/braze around it and see what happens.

Soundguy · Nov 7, 2005

If you do it assembled.. I'll bet you have a 99.9999999999999999999999999999999999999%
chance of cooking the oring.

Soundguy

coloradotrout · Nov 7, 2005

Ah.. so there's a chance it will be OK ;-)

I was planning to remove the connector from pump and pull o-ring. That 'end' is easy to get to. The other end is a bear.. I'm hoping I can pull it out from the motor/chassis and get enough heat on it to melt the solder w/o frying other stuff in the area.

slowzuki · Nov 7, 2005

So why is this fitting 250$? It sounds like a max 20$ fitting? Most hydraulic supply stores have hundreds of fittings, few would ever hit 250$ except like 2" fittings... Most will even crimp it on the hose for you for free.

Sounds like a plain o-ring boss (orb) fitting...

Bill_M · Nov 7, 2005

Colorado, yes you can silver solder the line to stop your leak. It is best to make a small patch out of some sheet metal or another piece of tubing close to the same thickness and actually solder that over the hole. This will give you much more surface area / strength than solder alone. The strength comes from the solder's "glueing ability". This was recommended by the hydraulic supply shop who we use at work and also the mechanics in our shop. ( We among other things, install hydraulic systems in trucks.)