Ok so I made a big mess : I think that I stripped a brake line hole in my brand new master cylinder ! I was trying to screw in a brake line but I did not realize that the fitting was a lil bit sideways. So when I found out how I was screwing the fitting, I unscrewed it and it took some tries to get it straight. Now it is screwed tight and straight.

So I installed the brake lines, no leak. Did a test so I pressed the brake pedal down : it's leaking from the fitting threads!

Is there anything to do about it or I absolutely need to buy a new master cylinder?

 

I searched for my problem on google and I found out this :

"Brake fluid should never even REACH the threads if the flare is doing its job. Remember, in flare fittings, the threads are PURELY mechanical."

Is that true for brake lines?

 

can you get it unscrewed and screwed back in? maybed put some plumbers tape on the threads and reassemble, or you could always duct tape it :p

 

Yes it true. The threads just push the flare on the end of the pipe into the fitting tightly enough to seal it up. If you're leaking through the threads, then the flare isn't held tightly or squarely onto the fitting. Brake pressure is pretty high when you push hard so it's not too likely that thread tape will hold. Try to get the flare nut to go all the way in or find a tap that can clean up the threads.

Brakes are kind of important to some folks (I have no idea why) so if you can't repair the threads to get it to seal properly, I suggest you replace it.

 

This is what I would do Go buy a new one being more careful!!!! this time

When you have time try and repair the other one or if like me it would sit for years then I would throw it out only to find I needed something off it.

 

Job done, new brake lines coming with pre-made fittings and flares did the trick, no more leak and it brakes like a new