Rebuilt Master Cylinder Material

What material are rebuilt master cylinders made of? The reason I ask is that I have one and new stainless steel brake lines. I have some seepage around where the lines connect to the MC. The front brakes line is worse than the rear brakes line because of the hard 90 deg bend the line makes out of the nut. How hard can I crank down on the flare nuts? Thanks.

 

Should be the same as the original. Rebuilts or remanufactured parts are rebuilt from original cores typically. Look at the lines to make sure the flares are in good shape and check inside to make sure the flare seats are in good shape as well. A trick I use is to torque the nuts, loosen them, torque them, loosen them, then retorque them. This helps the line flare to seat with the m/c seat. I do this with brake hoses as well. Helps minimize leaks and loosening of the lines down the road.

 

I appreciate your advice. But, I took the line back off, and it appears I have cross-threaded the MC. It's so aggravating because I also did this on the front brake line tee and had to get another one. I screwed the line back into the MC and torqued and loosened a few times, but it still leaks due to the cross-threading. I have a habit of turning simple tasks into long, drawn-out, do-over tasks. The line seems to had an upward push to it no matter how I bent the line, and it never would go truely flat into the MC. This made the flare nut push up as well, causing the cross threading. I pulled down on it while tightening, but it still cross threaded. Once I get the lines bled the best I can, I plan to drive it down the road to a local garage/muffler shop to have him put another MC on it. It needs new mufflers and pipes anyway, so I can kill two birds with one stone.