In the process of redoing brake lines at the wheels, and have never flared brake lines before. I am using polyarmor with the plastic coating, and it may be slightly too large for the 3/16" tool I am flaring with. Here is what I have done so far. I believe they look pretty good, but I am little worried this tool overtightens the second flaring operation and I don't want it to thin out the wall too much.

FYI I applied some anti-seize to lubricate the operation, so some of the metal coloring you see on the inside is that.  Even so, in the second image you can see a little bit of burring on the crushed over wall (despite my cleaning up all the edges at the start.) I am slightly concerned that I am crushing the metal in there.

First 3 images are the finished flare I think is good.  4th is the flare halfway done in the tool.  5 and 6 are the secondary flaring operation stopped halfway through just to see what it looked like.

 

Thanks for the quick help. While the 5th and 6th pictures definitely need more travel on the tool, i am wondering if I should stop it a little bit before the end so I don't crush the bent over metal. 

Edited January 17, 20169 yr by DaveR

They don't look too bad. The only real test is connect them and apply hydraulic pressure. Remember this is a metal to metal seal on that 45deg inner bevel you just made, so look for symetry and even shape on that inner bevel and ignore the outside.

I can help with the tubing prep. Three things are crutial.

1. Straight cut with perfect tubing roundness. ie must use a pipe cutter, never a saw.

2. Inside must be deburred. You must remove the natural inward ID reduction that happens with pipe cutters. I use a tapered round file

3. File a 45deg camfer on the outer edge all around. Doesn't have to be much, just try to make a nice consistent pass with a fine file.

4. Blow the tubing out to remove debris before assembling. 

Ok four things....

After reading a bit more about it, I definitely did a lot right, but I cranked down WAY too hard on the second step. I thought it would be like the first step and you wanted to bottom out.  Apparently not, so I will try again after picking up a tube cutter and try to find the sweet spot.

They look good to me.  I just replaced the rotten chassis lines on my DD Honda and I struggled to get them perfectly centered.  You shouldn't have any problems with those flares.

Excellent advice given above.  The tubing cutter is critical in getting a good flare.  The more you practice the process, the better your feel for "JUST RIGHT" will come.  One concern is the never seize.  Would that possibly contaminate the brake fluid?  That is some great stuff to use but I always have a very hard time cleaning off the excess since it really seems to coat the metal very well.  Does any one have a certain lube they use in the flaring process?  I usually use just a bit of spray lube in the process to smooth out the operation a bit.  Enjoy your project.  I did all the lines on my Datsun 2000 Roadster and it was a challenging but rewarding job.  Trying to replicate the factory bends is nearly impossible. The more I did it the better the lines came out.  John-Lugoff, SC