Replacing a metal brake line and flaring

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?

Use a tube bending tool to bend the line — you can do mild bends by hand — you can also get “easy bend” pipe that has a high copper content — no bending tools needed for that stuff

It’s not hard to use a flare tool under a vehicle, just awkward and you need enough space
— I would suggest you use some scrap fuel line and practice a few flares on a bench where you can get comfortable — use a C clamp for extra pressure on the tubing holder under the Jeep — I do it all the time

Remember you are making a double flare — using a little oil on the flare tool will help — you can rent the flare kit from the chain auto stores

You could always buy a pre-formed and ready to go brake line. What year do you have?

Either as stated above go pre-formed or get the easy bend one with the copper. Also If I remember correctly the brake lines have to have the double flare and also if going stainless they don't get double flared but gets a 47 degree flare instead of a 37 degree flare so they require a different flaring tool.


When I did mine I went with pre-bent stainless but wish I would of went with the easy bend stuff.

Thanks for all the help. I've learned a lot. 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.