when you are screwing in the fitting on the brake lines in to the porp. valve or to the brake caliper... do you just put tephlon tape or should you use something else

 

I dont think you are supposed to use anything. They should seal.

 

No, no sealer. They should seal at the flare, the threads don't need to seal.

 

They go together dry. No tape, no sealant, no nothing. Do wipe them off and make sure there's no dirt, of course. They're designed to go together dry. Putting anything in there will ensure that all of the surfaces do not mate properly and leakage is guaranteed the moment you step on the pedal and pressurize the system.

 

Yes, for a flared fitting - it is the cone mating with the cone of the valve. Tape will not hurt! It just won;t help either... It is the torque behind the b-nut that provides the sealing.

Tape is used for pipe thread joints.

 

There is automotive teflon tape that is much thicker than plumbing teflon tape, but it is for gasoline connections, not for brake line. The brake fluid instantly eats through it and melts it. A real bad thing if you get dissolved and shredded tape in your brake lines. Useless and damaging for brake fittings.
The tape would be used on fuel fittings that are not flared and not tight fitting. Such as the brass fittings that would mount to your fuel pump that the flared fitting connects to. The brass fitting should be softer than the mounting hole, so it would be worn before the mounting hole, that would be the situation you would want to use the tape, but only temporarily for an emergency. If the brass fitting is worn, it should be replaced with a new tight fitting one and they are actually cheaper than the tape!

 

I read somewhere recently that you should tighten the fitting to seat the flare, then loosen it and tighten it again. Of course I read this after I rebuilt my entire brake system with all new lines, only tightening them once. Hasn't leaked yet though!