Sealant on brake line fittings

[bfoldy]

I'm wondering if it makes sense to use some sort of sealant on the threads of brake line fittings to cut down on the likelihood of leaks? Maybe a teflon paste or is there really even anything that is made to withstand the effects of brake fluid?

 

[Viperwolf1]

No. The fittings don't seal at the threads. They seal at the flare.

 

[65 mustang]

The flare at the end of the steel line actually crushes (a little) causing a leak free seal. If there is a leak the flare is bad or the seat where it fits could be bad, no you dont need any "goop" there can be over 1000 psi in your system. Scott

 

[Dan74Bronc]

No. The fittings don't seal at the threads. They seal at the flare.

x2. The nut just pushes the flared end of the tube against the tapered cone or seat on the master cylinder, wheel cylinder, caliper or whatever you're plumbing the brake line to.

If the seat or flared end of the tube sealing surface is damaged (dinged or scratched)then you have the possibility for a leak.

 

[VT_Don]

Sealant is only used on taper pipe threads. Both NPT & NPTF. Straight threaded fittings rely on the taper seat to seal, not the threads. I've fired technicians for using Teflon tape on straight threaded hydraulic fittings. Just ignorant workmanship.
However, the conical, fitting seat that contacts the tubing flare may gall at assembly. This is more true of stainless brake components. So, I always use anti seize on the fittings and bleeder screws. Also prevents rust on carbon steel junctions. Water will follow vertical running lines and collect between the line & fitting. Doesn't take long to rust into a solid mass.