High pressure “Flare” vs low pressure “compression“. Compression fitting on a brake system is not safe!

 

Compression fittings will not hold 2500psi brake pressures during a panic stop.

 

Just look at the design. Ferrule is slid over a straight line with pressure from the nuts holding it. Under high pressure the line can slide out. Copper line isn’t legal either unless he is talking about copper/nickel which is common.

 

What 396325 said. Just because someone did it "successfully", doesn't mean it's safe, a good idea, or even legal. I do a fair bit of laboratory gas line plumbing for things like Hydrogen in my day job and have encountered some pretty disturbing "creative" cobbling using materials and fittings that shouldn't have been anywhere near a high-pressure flammable/explosive gas. Chuckleheads exist and shouldn't be the benchmark for a good plan.

And CuNi lines are great, but pure copper is WAY too soft. It can literally bubble out like a balloon and rupture. DON'T DO IT.

 

im just glad I saw the damaged line and decided to replace it. the union was against the cradle so unless you were under the car looking for it, you would never see it. jim

 

went to the local orielys they only carry steel lines, went to Napa, the warehouse has the copper nickle lines so went ahead and ordered one. the counter guy thought the regular steel line would be easy enough to bend but I showed him the first bend and he agreed I should just wait for the copper nickle line. jim

 

Indeed. The CuNi line is a dream to bend. Especially compared to the 316 SS tubing I usually work with. That stuff is HARD!! It ain’t cheap either at about $5/ft. And the bender I use costs about $300.
Fun fact: I had a 15’ section of scrap that couldn’t be used due to oil contamination so I started thinking, “Hey, this is long enough to make the line from the rear end to the PRV on the front subframe of the Camaro…” So, I took some smaller scraps to test out how well it flares. Well, my brake flaring tool certainly isn’t top of the line, but it’s not a cheap-o, either and I thought I was gonna break the arm off trying to do the 1st flare. And just forget about trying the second flare. Not happening. So then I start trying to research what grade of SS brake lines are made of. Not a lot of info out there, but found the golden bullet: it’s double annealed. AKA, wayyyy softer. D’oh! 🤡

 

Surely one of the FMVSS laws from years ago!!

 

just installed the distribution block, hooked the rear and both front lines. And yes! that copper nickle line is a dream to work with. next up, swap the master cylinder drop a line to the front (from the rear mc port correct?)
drop another line from the front port to the prop valve, then to the dist block. jim