Replacing a metal brake line and flaring

[bradleyheathhays]

I have a leak in the 3/16" metal brake line that leads from somewhere under the brake cylinder up front all the way back almost to the rear axle. The rearward 3 feet or so of the line is corroded and I'm hoping just to be able to replace that part of the line. I've got a piece of just straight prefab steel line that's already flared and has the hardware on it. My plan is to cut my current brake line just forward from where the corrosion is and disconnect / unscrew it at it's rearward point. Then I'll shape my new line, screw it into the rear connection and bring it forward and splice it into the existing line after flaring the existing line.


Problem is I've never flared a brake line before. It doesn't look too difficult in the videos but in all those scenarios they're putting the flare tool in a shop bench clamp and twisting things down super tight explaining that if the tool that holds the line isn't tight the flare tool will push it out of position when it's cranked down. My issue is I'll be doing this under the vehicle and won't have the advantage of leverage to get everything tight enough.


Any advice about doing this under a vehicle?


also


Any advice on how to bend this 3/16" steel tube? sand possible? bend tool?

 

[mark sr]

I've both successfully double flared brake lines and had the flare fail multiple times. Not sure if it's me or if it's harder to do than it looks. Personally I'd replace the line completely from one factory fitting to another. That way you know that entire section is good as the odds are the rest of that line will fail sooner or later.

There are several different types of tubing benders you can get although in a pinch I've used an aerosol can to bend the line around. The main thing is you don't want any sharp bends!

 

[bradleyheathhays]

Thanks for all the help. After consulting with my regular mechanics I just let them do it because the whole line really needed to be replaced. As it went up through the engine compartment it just got too twisty for me. Peace of mind.

 

[aggreX]

When I replaced rusty brake lines I chose the Cu-Ni lines. The Cu-Ni lines were more expensive but made the job much easier as they bend and flare with much less effort. The other bonus is they do not rust like steel lines.