Hydraulic brake tubing

[Dave Henderson]

An area of the 3/16 OD brake tubing on my old '93 Buick beater has a pinhole about 1/32" in diameter due to a single rust pit. Replacing or sectioning the lines would be a difficult task due to the complex routing and lack of accessibility.  It's even difficult to just follow the routing of an individual line.  I am mulling over the possibility of using JB Weld for the repair.  I went on line and found mostly negative comments about doing so, saying it wouldn't withstand the pressure, and that DOT 3 fluid would soften the material.  Notwithstanding, today I read a generic repair article which said JB is good for 3,960 psi, which I believe exceeds the maximum pressure during even extreme braking by at least 2 to 1.  However, that psi mentioned would apply to the compressive strength, I think.  I don't have a spec for the tensile strength in regards to strength of the bond to the tubing, and don't know how to assess the possibly of it separating from it.  As for the DOT3 fluid, If it in fact would soften the JB, I could change to silicon fluid, if that would work.   I have made an inqury to the JB Weld maker but they have not responded.   
So, what do the experts think,  would you do it, if so would it be necessary to change to silicon fluid?  What are the pitfalls if any,  is this an easy way out that would succeed?  Your comments will be much appreciated!

[Matt Harwood]

I think any kind of external patch or epoxy on a brake line will fail in pretty short order, probably the first time you step on the brake. There's just no way it can adhere strongly enough to the steel against potentially several thousand pounds of pressure coming from within. Even though this is just a beater and replacing a brake line is a real pain in the butt, it's a safety thing and that really matters. JBWeld corporate will NEVER respond to your inquiry because they know it's a very bad idea and they don't want to do anything even close to giving approval for it. If you have a flaring tool, you can get unions and just cut out the section that's bad, flare the ends, and splice in a small length of line. Not ideal, but far, far safer than trying to patch it externally with some kind of goop. 

 

If it really looks like an awful job, you might also just try farming it out to a local shop. I had this happen to my car in the middle of winter when I was in college. While I probably could have replaced a brake line laying under the car in a frozen parking lot two days before Christmas, I limped it to a local garage instead. For like $50, they put in a new brake line in about an hour. It wasn't pretty, it wasn't even close to the same as the factory routing, but it was safe and secure and on a beater, who cares?. 100% worth it and it never leaked again. There's no dishonor in letting someone else do the jobs you hate--your time is valuable, too. The cost might not be as astronomical as you think compared to doing it yourself, especially when you consider the value of your time.

 

Hope this helps!

[46 woodie]

Dave, two of the things that you don't compromise on are your brakes and your steering. Do the job right! Can you imagine what your insurance company would say if God forbid you had a serious accident and they learned you used epoxy to repair your brakes?

[60FlatTop]

Moisture absorbed into the brake fluid rests in the low areas of the lines and wheel cylinders. It will corrode the inside diameter of the line and reduce the thickness. It's all shot. It will rust the steek plugs out of your antilock unit, too!

 

You can test the rest of the line. Put the jaws on a vise grip on the sides of the line and gently increase the pressure with the tightening screw. The bottom of a bad line will crack open like a lobster tail. I know that fitting over the rear crossmember is a bear. Early '60's Caddy's were really hard to do.

 

Years ago my Daughter was living and working in a city 20 miles from me. She called from her work parking lot with no brakes. I told her I would be there in 25 minutes. I arrived and there was a big pool of fluid under the driver's door and tears on her cheeks. I told her to take my truck and I would bring her car back when it was fixed. She asked how I was getting home. "Your car" I replied. She got a case of the stutters and said it didn't have brakes. I told her I didn't need them. The expressway was close. And we left, me cautious and her in a daze. I told her it was the male mystique.

 

That's the car that blew through the antilock plug. I bypassed it. You might want to poke an awl into that while you are at it.

Bernie

[JACK M]

Don't do it, absolutely not. It wont work dependably.

As Matt mentioned, route a line around the obstacles.

[viv w]

Don't mess around with old brake lines. If it has a pin hole in one area, then chances are the rest of your brake lines also need replacement. Brake lines corrode from inside and you wont see a problem until it is too late. Replace ALL your metal brake pipes urgently.

Your life depends on it and so do the lives of your loved ones.

Viv

[Frank DuVal]

REpoxy holding hydraulic pressure. Sure, just wrap it with electrical tape to be sure. Then tow it to the scrapyard, as you might kill yourself and others if you drive it!😧

 

DO NOT compromise on safety parts, like brakes. Running is optional, stopping is mandatory.

 

Do not use compression fittings either. Illegal in this state. Why? Improper installation and they fail. See above about killing others in crash. Inverted flare fittings only. 

 

I have spliced brake lines, with inverted flare fittings, to avoid spots that looked hard. But now I just replace it all, since I learned the section I didn’t replace had to be replaced later. Just do it once.

 

I use Cunifer for the brake tubing, easy to bend and flare. You may also find some of your lines have bubble flares instead of the typical inverted flare on one end. You can make these with standard inverted/double flare tool. Instructions on Internet.

 

Always do a hard harder test on brake systems of older (as new as 5 years old in salt states) brake systems. Step hard on brake , then step harder. If non-power brakes, grab steering wheel and pull yourself up. A good brake system will hold this pressure. If something brakes, be glad it happen do in the driveway and not at a big intersection.

Edited November 22, 2018 by Frank DuVal
Auto correct screwed up (see edit history)

[GARY F]

Route it anywhere to get to each end like they said above. just leave the old line where it is. You only get one chance to stop.

[SC38dls]

If you had an accident and someone got hurt due to loss of braking, how would you feel? What about the liability you may face if that person found out about you TRYING a short cut brake fix?  Do it right or don’t drive the car. Be safe 

Dave S 

[DavidMc]

Dave, 

 

Adding to what others have said,  you quote a strength figure of 3960 psi for J B Weld.  What is that a measure of, is it tensile strength, shear strength , compressive strength?   Without more information it is meaningless and probably irrelevant.  What you are looking for is bond strength, the ability of the the JB Weld to bond to the tubing and to maintain that bond  over time when subject to temperature change vibration, effect of the brake fluid etc.    The use of the word "Weld" in the product name is misleading, a weld occurs when the materials are heated and fused together at their melting point.   J B Weld is just a glue .   

[mcdarrunt]

Get you some Cunifer ( or any copper/nickel) tubing. It doesn't corrode from water and is easily bent to shape without a tubing bender. Volvo started using it a good while back and they are the safety leader.

[PFitz]

 " .................... I have made an inqury to the JB Weld maker but they have not responded. ..............."

 

I'll be shocked if they do respond that that's an acceptable use of their product.

 

Replace the line is the only acceptable answer.

 

Paul

[Frantz]

5 hours ago, mcdarrunt said:

Get you some Cunifer ( or any copper/nickel) tubing. It doesn't corrode from water and is easily bent to shape without a tubing bender. Volvo started using it a good while back and they are the safety leader.

Depending on how much life is left in the old Buick this wouldn't be a bad option. Of course... it will take away some points when you get it judged =-D

[John348]

On 11/22/2018 at 10:52 AM, Dave Henderson said:

 I am mulling over the possibility of using JB Weld for the repair.  I went on line and found mostly negative comments about doing so, saying it wouldn't withstand the pressure, and that DOT 3 fluid would soften the material. 

 

It appears that you are asking the question on multiple sites with the hopes that someone will agree with this idea to justify using it. 

 

Needless to say I am in agreement with everyone here and it should not be used for this type of repair the involves the life safety of yourself and others. While the JB weld most likely will not fail the material beneath the repair is in question, and most likely will fail at the next weakest point. 

Replacement of the line is the only repair option you have 

Edited November 23, 2018 by John348 (see edit history)

[plymouthcranbrook]

 

You can always go in each direction until you find good line and replace the bad part using Pressure fittings. I have done that several times and NEVER had a leak or brake failure. 

[Dave Henderson]

Thanks to all for your views concerning the feasibility of using JB Weld to repair leaks in brake tubing.  For stated reasons the idea had lots of appeal.  The use of adhesives rather than welding to join metal body panels is now a reality, and that inspired me to consider taking that tack.  Of course safety is the first concern, and thus another "bright idea" down the drain.   

[dep5]

On 11/22/2018 at 10:52 AM, Dave Henderson said:

. .
So, what do the experts think,  would you do it

 

Makes me think a thoughtful person would ignore your past and future posts. To be charitable, maybe this was meant as an April Fools comment and you got the day mixed up with Black Friday.

[Rusty_OToole]

Replace the line or have a mechanic do it. Shouldn't cost much to have it done. I have replaced many brake lines, if you want a cheap job there are safe ways to do it. Such as leaving the old line in place and fastening the new one to it with zip ties. Or routing the new line in an easier more convenient way.  This is a common problem as brake lines are installed at the factory before the body, suspension etc are put on .

 

DO NOT use JB weld. Just replace the line or have it replaced.

 

DO NOT use compression fittings. They are meant for low pressure not high pressure brake lines. You could cut out the bad part, flare the ends and put in a section but this is usually harder than replacing the whole line.

 

I can tell you how I replace brake lines on old cars. First cut the brake line off at the fitting with side cutter pliers. Remove the old fitting with a socket wrench. If you can get the old line off you can use it to measure and bend the new line, otherwise measure carefully and get a new line. It is always better to get a longer line than you need, somehow you always need some extra length, if it is too long put an extra bend in to take up the slack.

 

Fit the new line, tighten carefully, be sure it is fastened down to the factory points or at least as many points if not more. Now you need to bleed the brakes. I always heat the bleeder in case it is stuck this avoids broken off bleeders.

Edited November 23, 2018 by Rusty_OToole (see edit history)

[Restorer32]

There is an old saying that goes something like this... "Anyone who attempts to repair a brake line with epoxy or any other type sealant has a fool for a mechanic". That being said people  sometimes do stupid things. We had a 1960's car that came into the shop for rust repair. A previous owner had installed a tow hitch from a truck that was meant to be thru bolted to a truck bumper. It also had a long brace that went back under the truck and was meant to be bolted to a cross member. The car had no such cross member so they just welded the brace directly to the gas tank. No offense meant but hopefully we have shamed you out of ever considering the type repair you were contemplating.

[Bhigdog]

Yes. JB Weld should never be used for brake line repairs. Bazooka or Double Bubble is a much better choice for repairs on critical components............Bob

[Frantz]

3 hours ago, Restorer32 said:

There is an old saying that goes something like this... "Anyone who attempts to repair a brake line with epoxy or any other type sealant has a fool for a mechanic". That being said people  sometimes do stupid things. We had a 1960's car that came into the shop for rust repair. A previous owner had installed a tow hitch from a truck that was meant to be thru bolted to a truck bumper. It also had a long brace that went back under the truck and was meant to be bolted to a cross member. The car had no such cross member so they just welded the brace directly to the gas tank. No offense meant but hopefully we have shamed you out of ever considering the type repair you were contemplating.

Off topic but did you get up to the museum while the yellow Anderson was being shown? It had a hitch bolted (or maybe welded, I forget) to and only to the fuel tank. Worked since 1920!

[Bloo]

If there is no obvious reason it rusted out in that one spot, (like battery acid dripping on it, or a low spot that collected the worst of the rotten brake fluid), then ALL the tubing needs to be replaced.

 

That isn't what you asked though. You asked whether JB weld will hold in this situation. No.

[nickelroadster]

I was somewhat heartened by the fact that there was not ONE response that suggested that it would be okay to use JB weld.

[51dyno]

NAPA had replacement lines for my van , might give them a call . Brake lines are required to have DOUBLE FLARES  when splicing in a section and doubtful a good mechanic would do that due to liability . Do it yourself and could cost you your home .

[Frank DuVal]

Any parts store aka FLAPS (friendly auto parts store) has steel tubing in premade lengths with double (inverted) flare, bubble flare and metric flare. They should also carry the inverted flare fittings to join sections together.

Common for mechanics in salt areas to replace sections of tube instead of the whole tube, since the rust through is external and not internal in these cases. Maybe not anymore due to lawyers, but I have seen it on trucks brought down from New York area.😉

 

Of course, they might have just been “used car” repairs.😁

[tripwire]

Back in the day when I was in the service dept. at the local Buick dealer we ran into this a lot here in the state of Vermont.  What would bring the car in was either a brake or fuel leak.  Many times, the area that was leaking was at or near the pipe clamps.  It was quickly discovered that other soft areas were present at nearly every other pipe clamp.  So, we'd end up replacing the pipe from one end to the other.  We'd also replace the fuel pipes because they were in similar condition.  There were other instances where we'd see a car come in with a fuel leak and we'd  see brand new brake pipes.  The customer had just been somewhere else to get the brake pipes fixed and the other garage failed to do their customer the favor of replacing the fuel pipes at the same time so the customer was forced to pay twice.

 

So, my recommendation is to replace all of the pipes and be done with it.

 

Wes in VT 

[60FlatTop]

1 hour ago, tripwire said:

The customer had just been somewhere else to get the brake pipes fixed and the other garage failed to do their customer the favor of replacing the fuel pipes at the same time so the customer was forced to pay twice.

 

 

That one made me smile. Somehow the customer never sees that as a favor. "Yeah, they get you in the shop and the look for all kinds of problems." Favors and charitable acts are kind of like touching a hot stove if you do enough.

 

When I was in High School I never had to go to the auto parts for brake lines. Just go over the the rear end pile that had been cut out of junked cars. I could always find a length of shiny new line, lots of them. Kind of an indication that the mechanic could have suggested a cheaper, but greater favor.