2001 with the standard rusted brake lines. Flared new lines to both front corners and to the bottom front of the aluminum valve. the original leak was the line on the frame rail from the brass block going to RF. All lines needed replaced . All new correct nuts and line. Of course the only leak is from the bottom front of the valve. The original came off with no problem and new one seemed to go on by hand with no problem. I have tightened the He-- out of it and stopped before I striped it. . Several attempts and out of desperation ( I know not recommended ) I cut off the original to the valve and used a compression fitting to the new line. Same problem . No matter how tight it is it is leaking between the bottom of the nut and the tube . Any ideas ? I can't see the bottom of it without taking off all 4 lines . It goes on straight and seems to tighten fine . using line wrenches so no slipping .

Thank you

 

New tubing is (metric) bubble flare and not (english) inverted flare, right?

The flare makes the seal, not the threads. Sounds like the flare may have dirt on it or may have gotten bent at some point.

 

Compression fittings are a VERY bad idea for brake lines. They simply are NOT designed for the kind of pressures brake systems can develop. In most states, it is illegal to use compression fittings on brake lines......

 

yes , it is bubble. the new nut fitting is 10x1.0 for 3/16 tubing. The depth and seating lip looks the same as the original. As mentioned I also tried the original nut and flared end and had the same result. . Are you thinking something is bent in the seat on the bottom of the valve ?

 

I am using this tool to flare the ends .