The Stovebolt Site Forums The Shop Area Driveline leaking brake line joints

New brake master cylinder, stainless steel brake lines (purchased pre-bent), and new flex hoses. Kept the original brass T-joints. Tightened all joints securely. All joints leaked. The master cylinder joint wouldn't even come close, by several screw threads, until I greased the threads on someone elses advice. But that did not help most of the other joints. Do I need new bras T's? What else?

Denny Graham way back posted on this and the compression of the brass T's threads over time making sealing difficult. Mine did not seal under almost exactly what you described so I sourced new ones, they sealed right up so I think Denny was right.

Yes you need new brass fittings if they won't seal. Someone may know of a fix but the tubing is so much harder than the brass that once the brass fitting is deformed to the old tube the news may not seal. I did the same thing but only had one that would not seal. I replaced the brass fitting and that fixed the seal.

I have to admit stainless brake and fuel lines really make it hard to seal things. I won't use stainless again because of this, but THIS particular truck its necessary. You can get stainless fittings that may help. Don't use any plumbers tape or sealer and loosen and retighten several times to see if they will seat eventually. You will get it to seal, keep at it.

The next truck I do will be using the new nickel alloy solution. No corrosion, same as stainless and much easier to work with.

....even though I've seen recommendations to loosen/tighten a time or two I do NOT like to do it either, Deve. However, since I'm prone to squeeze a nut or bolt till it hollers, I generally put a good tightening on brake lines/fittings and then IF they leak I can "snug" them a little and be OK. Its only MY OPINION but sometimes I think we tighten stuff a lot more than we need to, or at least it was my opinion. There is a time an place for everything but twisting the fittings usually gets you in trouble.

When I bought mt SS brake lines for my Suburban, 5 or 6 joints leaked (reusing all the original brass fittings/joints/blocks). The vendor, Inline Tube or Classic Tube, said this was common. They suggested gently tightening and untightening the fittings a few times, ending with as snug tighten. That was about 10 years ago, with no leaks/seaps since then.

http://www.classictube.com/resources/tech-articles/238-making-stainless-painless

http://inlinetube.com/top%20buttons%20bar%20orange/commonfaq.htm

I hear you Tim, and I'm not going to say I've never did it ... I just don't like to!

I did not like doing it, either, Alvin. But, I figured that I might as well follow directions, even though it caused me to cringe.

Really, stainless steel is unsuitable for brake and fuel lines. Its tensile strength and hardness practically guarantee leaks at every joint. So, since it is so stubborn, you have to just back off the nut, tighten, back off, tighten until it gives in. It may look pretty and be touted as corrosion proof, but the newer nickel alloy stuff does the same thing, shines up really nice, and works much smoother.

Scarred brass will not reseal. Good news? You can still get the replacement parts. Stainless is hard to work with, Copper/Nickel is better. Old lines..I think were annealed steel. Rust rather well. You will know what a "banjo" fitting is when you are done. That is a plus. Are we having fun yet?

Bob I had the same problem as you and apparently everyone else. I thought what the hell I will fork out the extra cash for the pre-bent stainless lines to my project moving. Every joint leaked and I mean leaked good. I did the loosen and re-tighten method and figured the brass tees would fail before the steel flare nut so I kept wrenching them down. They did eventually stop leaking. Hope this gives you some hope. Good Luck

I had this problem on other trucks and now I am in the position to start all this over again. I have the dual MC installed and plumbed (thanks Grigg for the tip on Brakequip products) and am getting ready to bench bleed and then bleed the system. Its stainless too and I fully expect there to be leaks at every joint.

The reason loosening and retightening works is the same reason why a hammer and dolly work to persuade body parts into place. The flare needs to be taught how to shape itself against the brass, in my case stainless fittings. I sure hope I know what I am talking about. LOTS of fittings to go through. I will keep everyone posted. No choice in any case. Have to do SOMETHING! Stainless is particularly hard to work with. If you have ever tried to use a flaring tool with it, you know. I wont use it ever again since there is something better out now that polishes nice and works much better in the nickel tubing that's available. NiCop? I will do more research on that when I start another resto. Good luck!

I opted to go w/the pre-made steel lines when I redid my brakes. I reused all the brass blocks and tee blocks. I had two leakers, one at the new MS and the other at the block on the right rear wheel cyl. A loosen and re-tighten stopped the leak. 4K miles later they're still holding strong.

The lines fit perfectly.

Dave

On sigle-flared & double-flared fittings, the seal is at the male/female flare, not the threads. A dab of dielectric grease on the threads & the flare, will allow for a more smooth set, when tightening & loosening fittings.

I agree with Tony that the threads and the flare itself should have some sort of lubrication, personally I use some brake fluid. I have seen what appeared to be a perfect double flare give trouble and found that it was flared to wide. The outside edges of the flare caused it to not seat down into the fitting. When doing the second step of a double flare caution should be used to not push tool to far and make the flare bigger than it should be.

x2 Don Stocker. I had to flare a fuel line and made it bit too wide as you described. Had to shave the OD down a bit to get it to fit.

Deve - do you actually work in your shop? That place is spotless and I am jealous.

Its a funny story, NOT... I started my adult life in the US Air Force. Since high school I was a wannabe mechanic, so I spent a lot of time at the Base Auto Shop. It was a place where anyone on base could take their projects. Problem was, you had to clean up behind yourself. Oh not your normal clean, Stupid, over the top clean. If you got a drip on the concrete, you scrubbed it with kitty litter until it was gone.

I am the ONLY one who works in my shop, and somehow I like it being very clean. In fact, I probably spend as much time cleaning as working on the projects. The front half of the building I built myself is a commercial printing business ran by the wife, so I cant be tracking dirt into her territory! Clean is a state of mind and a habit you can easily get into. Just takes commitment. Many people agree I should be committed.

I know in the Speedway catalog, they don't recommend flaring the stainless brake line they sell, they recommend using ANSI fittings on the lines..... I think that is what the fittings are called.

John

AN fittings. Standard Army/Navy fitting. Adopted for all the obvious reasons. 30 degree single flare. Easy to find fittings. Ask any "Hose" shop they will be glad to help.
Clean shop? Air Force trained a lot of us. Even have labels on the tool box. Miss the cut out foam for instant inventory. Just too much time and money.

Well, to make you sick.. my toolbox has all the foam cutouts for everything. Black foam in my craftsman boxes and drawers so it doesn't look tacky. I just found it worth the trouble because then if I misplace a tool, there isn't any question about what I am missing. As forgetful as I am, I found it necessary!

With the Brakequip Flaring system, you can do very accurate and clean double flares on stainless. I have done a lot of that lately. If you have one of those kits in the little plastic red box... fuggetaboutit!

With AN fittings, you will still need to flare the tubing.

Yes you will. But a single flare is rather simple and flaws are easy to see. So, why double flare? It provides a "softer" connection and less wear on the fitting.
OK Deve, you convinced me. I will look for some foam this winter. I thought I would use 2 colors, One in the bottom and one to "shadow" should make the missing items stand out.

What is this foam you guys are talking about? You mean like flat foam cut out in the shape of the tool?

All I got in the Air Force was a crappy canvas bag for everything. I still carry one with tools in the truck.

Dennis

Nothing to do with leaky brake line joints anymore, but I use a 1/8" thick liner at the bottom of each tool drawer, followed by a 1/2" thick piece that's cut out to fit the tool using a very sharp hobby knife. IF I am afraid of slippage, I use 3M adhesive spray to glue them together. The socket drawers are the worst as far as patience, but if you take your time, you will really appreciate the time it saves in knowing whats there and whats not. I am sold on the idea myself.