Originally Posted by N_Jay
New soft copper washers.
Not reused ones, and not hard copper.
You can reuse the factory copper washers no problem. As a matter of fact, they work better than the new ones that come with replacement calipers.
The factory washers are thicker, they also have ridges cut into them so they seal better with less torque.
Note: they have to be the ones that came off of that particular vehicle, and reinstalled in the same orientation that they came off.
Originally Posted by Just Me
teflon tape on the threads?
remember it gets HOT.
Odd, i've never had an issue
The leak is not on the threads most likely. I'm betting it's it's coming from the copper washer area by the bolt head. Note that these use banjo bolts that are basically hollow to allow fluid to pass through them.
No sealants, teflon tape, or any other chemical may be used in a braking system except for brake fluid itself. It is vitally important that the system seals itself mechanically. Not only does the system get extremely hot, it also is under a considerable amount of pressure (think 2000 psi in some cases).