Is there a good, safe way to seal bleeder screw threads for vacuum bleeding? I tried vacuum bleeding for the first time yesterday and I love it, except for all the air getting pulled past the threads.

 

The bubbles enter and leave the bleeder. They don't flow "upsteam" into the caliper. Don't worry about bubbles!

good luck

 

That's exactly why I eventually bought a pressure bleeder.

The best I've been able to do with a vacuum bleeder, is to put a nice bead of grease all around the base of the bleed valve where it screws into the caliper body. It's pretty easy to miss a spot with the grease, and have it leak anyway. You have to kind of smear or push the grease down into the corner between the bleed valve & the caliper body.

What Texas says is true if you're flushing the system and there isn't any air in there to start with. I got frustrated with the bubbles when I was trying to decide when I had gotten all the air out of the system.

 

Then how are supposed to know when all of the air in the lines is actually out, should there be any in the lines?

 

Bubbles in caliper cause slugs of air. Only rarely is it necessary to bleed air; caliper or hose replacement. I only have bled for fluid replacement.

good luck