How disconnect brake lines?

[Daryl]

Why do I feel like this should be a straight forward, easy job? All I’m trying to do is disconnect the upper part of the front brake line. I put a 15mm on one side and a box end 7/16 on the other. Used opposing force to bust it loose. Wouldn’t budge. Tried turning clockwise in case it’s reverse threaded. Again, nothing.
It’s REALLY frustrating when what should be a relatively easy job turns into a PITA! :-(

Even hit it couple bursts of PB Blaster. Nothing. Bottom bolt 5/8” broke loose easy enough.

 

[Chip66]

With age, brake lines can become impossible to disconnect without destroying them.

To stand a chance, you definitely want a good set of line wrenches that fit the hex really well. My Gearwrench set has served me well over the years. Project Farm recently did a good video comparing different brands.

When all wrenching fails it's time to consider destructive removal and buying new or patching the metal lines.

 

[badass98svt]

I highly recommend NOT using standard wrenches when working with brake lines. As mentioned above, grab some line wrenches, you'll be glad you did when you're not striping anything out.
Spray the area with some PB Blaster and let it sit for a bit.

 

[PinkieT]

I've even redneck engineered my line wrenches when I feel them slipping by clamping down on the working end with a set of vise grips.