Repair steel hydraulic line

[Pixie]

The other day I asked for suggestions about repairing a badly bent line and the responses were informative and mixed.
Since then, I've found another Eaton/Weatherhead product that is a hose end/ ¾ ferrule.

So I have lots of choices:

Weld on a fitting.

Braze on a fitting

Silver solder that fitting.

Use the ferrule fitting.

What is the difference between braze and silver solder from strength and vibration perspective ?

A Master plumber said vibration was a bad idea with ferrule type fittings. What do you think ?

I'm avoiding welding because I'm not very good at it and there is only a generator where the machine is.

Thanks for sharing your experiences and opinions.

 

[nowing75]

We had a hole in a line on the boom of a cat excavator. We silver soldered it until the new one came in. Have used compression type fittings on our pull pan with good luck.

 

[Scrub Puller]

Yair . . . Pixie.

Many original hydraulic fittings were assembled with silver solder and there used to be ferrules available for joining pipe. A couple would be very easy to spin up on a lathe and you could replace the bent section with a piece of identical pipe.

Silver soldering is a simple process but you would need oxy and you should use what we call "bluetip" which is 50/60 per cent silver and will suck right in there when the heat is right provided you leave a bit of clearance and have the joint well fluxed.

Cheers.

 

[mitch504]

I have brazed many a steel line over the years, with good results if I didn't get careless with surface prep.

I used the Weatherhead compression fitting hose ends (what you are calling ferrule fittings) to replumb an entire A-W motorgrader restoration project with no problems, but that was only a 2500 psi system.

For the last couple of years, I have been using the Eaton compression fittings that go to standard JIC males with real good results. It doesn't hurt that they only take 2 wrenches and a tubing cutter to install, in minutes. They can be used with any male JIC fitting, so you are not as limited as you are with the hose ends.
The part # for a 3/4" is FC2875-12. For other sizes, just change the dash number.

Good luck,
Mitch

 

[Nige]

The problem these days is that very few systems run on as low a pressure as 2500psi like Mitch describes. 3500psi would be kind of normal, 4-5,000psi would not be extraordinary. With pressure like that you have to be VERY careful what you're doing. As a company-wide policy we do not allow any type of repairs or modifications to steel hydraulic lines. I have my own opinion about that policy but will not voice it here .........

 

[lantraxco]

Silver brazing (we all use the term "silver solder") is better than using normal brazing rod and much more expensive. The result is stronger and the silver acts as a wetting agent to aid proper adhesion to the steel parts. YMMV

 

[Scrub Puller]

Yair . . . Nige makes a very valid point about the increase in what are considered to be "normal" operating pressures.

I really am in no position to comment and too lazy to research the subject but generally speaking high grade "silver solder" and sleeves was the preferred repair method even for such items as injector lines and we used it to fabricate the very complex arrangement required to get 5000 psi to the hovercraft lift fans . . . the tubes ran within the aerodynamically shaped air flow straighteners and there was no room for conventional fittings.

Cheers

 

[John C.]

I suppose silver solder works real well on new pieces but nothing works better than an arc welder and skilled operator for time sensitive repairs. If I am repairing a cracked fitting, I drain the pressure off the line and remove it. A blow off with ether and then air pressure works best. I'll grind the crack down some and shine the surrounding area if possible and then weld up the problem.

Tensile strength on brass is only around 2,500 PSI so a perfect pass is only good to that working pressure. If you put that on you will never be able to go back and silver solder or weld over it. Mechanical fittings work well enough for the low to medium pressure and flow systems. When you are working with high flows and pressures in extreme duty cycle items like big excavators I generally prefer to replace whole lines or fittings rather than trying to weld them back together.

 

[Pixie]

Thanks very much for your thoughtful responses !
Ya, I'm thinking a Cat …even a little 307 probably runs more than 2500 psi.

I like the simplicity of the compression/ferrule fitting and it's available locally.( ¾ was available… measured today and line is ⅞" plus a little paint )
The parts store is trying to tell me that '98/2' ( tin/silver) is silver solder ( package says 8,000 pounds tensile strength). I'm not falling for that right off… and they don't have the fitting to solder on….
Which got me wondering how they can measure the strength of something as thin as a solder joint and how that really applies….

I'm going to go talk to a couple heavy equip mechanics tomorrow and see if they are willing to share their secrets or parts .

A friendly and good welder will be in town next week so I'm still weighing options.

It is a personal use machine but I don't want to be fixing it all the time !! ( I have other machines to fix, too LOL )
Joan

 

[Nige]

Just remember that "pounds tensile strength " isn't the same as psi ...........

 

[Delmer]

Which got me wondering how they can measure the strength of something as thin as a solder joint and how that really applies….

Brazing is not dependent on tensile strength but on shear strength, the fitting has to pull off to fail. That's how I've heard it explained anyway.

98% tin is called silver solder when plumbing with copper pipe, but the silver solder I think you want is actually a brazing rod, needs more than a little propane torch to use.

 

[stumpjumper83]

Since your not working on an antique, obsolete, mfgr closed up 50 yrs ago piece, why not just replace with new and be done with all the struggle and possibility of failing in an inopportune moment. Or even calling a salvage place and buying a used line.

 

[Pixie]

There are no salvage places around.
I'm guessing the new lines would be more than $500. Kind of out of my budget.
It is presently one line, the length of the boom; about 18-20 feet.

Solders are usually kind of soft so it's hard for me to picture their strength.

 

[Scrub Puller]

Yair . . . Just to add to the discussion.

The "blue tip" I mentioned is apparently 45% silver, I thought it was higher. It is the stuff I use to join bandsaw blades and I can't ever imagine it blowing out of a properly constructed hydraulic fitting if correctly applied . . . it is very easy to work on pipes, band saw blades not so much.

Cheers.

 

[Delmer]

Forget the word solder, it's a type of brazing rod that is used just like any other brazing rod, in this case with a sleeve of some sort.

 

[td25c]

Also have had good results repairing steel Hydraulic lines & fittings with arc welding . Generally use 6011 rod . Have had good results brazing smaller thin wall hydro lines as well . Lost count of how many times we have done it . Works fine until the operator lets a tree limb rip the line off again . LOL !

 

[Twisted]

I've either welded or brazed more that I care to remember. It works well if you can get the oil off & clean them up. I just did another one today.

 

[1466IH]

I have never had very good luck with brazing and prefer to tig weld personally. I guess my biggest problem is knowing how to do it right. With the proper guidance or instruction and technique brazing would probably be easier but i had a line one that i tried brazing 4 times and still had pin hole leaks so i cut out all the braze, made a patch piece to cover the hole and welded around it. I carry a Hi-Freq box on my truck that plugs right into my big blue and away i go. usually the hardest part is getting the line off and on.

 

[Deeretracks]

I've brazed a ton of hyd lines in the field. The biggest issue is getting it clean enough. Just a tiny bit of oil or grease left in the joint/crack and you'll get pinholes that **** oil.

 

[1466IH]

maybe that is my problem. I always figured the open flame would burn the contaminates out lol