I've got a set of Brembo M4's on my SD. The calipers have two nipples each. One on the top of the banjo bolt (this one is not the problem), located on the inner half of the caliper, and a stand-alone nipple (the problem nipples) on the outer half of the caliper. Fluid weeps at the base of the nipples, so the fluid is coming up through the threads. I've torqued down both nipples pretty damn good, and I'm afraid I'll snap one off if I try to torque any further. I've spoken to the guy that I bought them from and he said that a crush washer is NOT used with these nipples, that I should try some thread sealant.

Thoughts on this? I'd hate to wreck these calipers...

Brake bleed nipples bottom out at closed position. They seal from compression at full closed. a replacement nipple is in order. Thread sealant is not a solution.
Google brake bleeder nipples and veiw images. All else is self explanatory.

Gotcha. Guess you really can't torque those nipples down at all. Touchy Touchy

Well, after about 150 miles of street riding, while having fun with the front brake, they haven't weeped. When I would test to see if the system was buttoned tight, I'd basically beat the shit out of the calipers. Heavy heavy dragging, so much so, that at times I was pushing my front tyre across the pavement. So, she'll only weep if the fluid gets super hot.

That is my plumbing motto also. Do nothing and hope it fixes itself. It usually does, if I never place it in veiw again.
Good for you.

I have the M4s as well. First day I fitted them I had a slight weep as well so I tightened them further (not sure how tight) and since then they've been fine. I used 2 washers at every end and the weep was only from the line nipple, not the caliper nipple.

I am pretty sure they sell a "kit" with the nipples and washers. I had this problem with my clutch and back brakes and found that they sell the kit. Must be a normal problem