wrote in message
...

Actually there is no commonly used method of bleeding brakes where
leakage past the bleeder screw threads CAN cause a problem, and the
bleeder screw seals with a tapered seat so has no need for a
troublesome deterioration prone "O" ring. The only way I can see it
being an issue is if you attempted to draw the fluid into the system
through the bleeder screws by applying a vacuum to the top of the
master - which would be a REALLY stupid way to attempt to bleed a
brake system on so many counts.

I've replaced brake lines and/or wheel cylinders on every vehicle I've
owned, since I keep them in good condition a long time. The thread
leakage had never been an issue for me until I had to diagnose and
cure a spongy pedal, and couldn't distinguish leakage at the bleeder
from air in the lines.

The advice I was hoping for was a recommendation of a compatible or
insoluble heavy grease to put on the bleeder threads. The only "brake
grease" I have is for the caliper slides and rear self-adjuster, and
its strength is a high temperature tolerance to keep it off the
friction surfaces rather than compatibility with the fluid and rubber
cups.
http://en.wikipedia.org/wiki/Dropping_point

-jsw