This is exactly what happened to me, that's why I posted. There's something especially infuriating about something that used to work that suddenly doesn't because suddenly it's not about making progress in a task, it's also about figuring out why your map for the situation is now wrong. But you don't know how it's wrong, you just know that it is.

 

Is there a special procedure I'm not following to bleed empty calipers? Should I be looking at new copper gaskets that go above and below the brake line where the bleeder valve goes?

 

Just try the way I suggested above.

Bleeder screws don't usually have gaskets. Are you referring to the crush washers that go on the banjo bolt? If so you should never really reuse those.

 

If you want to learn it from where I learned it, look up reverse-bleeding on this site. I'll explain how I do it:

Setup: M/C cover off, surrounding area protected from spills with something impermeable (ie not rags). Put the box-end of a wrench on the bleeder screw. Pull new fluid into the syringe and attach its hose to the bleeder nipple with a zip-tie to make sure it's tight. Invert the syringe and let the air bubble come to the top by tapping it. Keep your eye on the M/C, open the screw, and start pushing the fluid into the caliper. When you run out of 'stroke' on the syringe, close the screw reload the syringe without introducing air. Keep going until you see fluid in the M/C. Close the bleeder and do the left caliper.

If everything went well it should be perfect when you finish because this method doesn't allow air to be trapped anywhere. It all comes out the top as you push the fluid through.

Also make sure the return port in the M/C is clear before you start. Agree about not re-using copper gaskets. OP if you haven't touched them they don't need to be involved, but you said full rebuild. For any of the banjo bolt connections that were opened, you should make sure the little port is clear and the threads are clean, add new gaskets and torque to spec, then do the reverse-bleed I was talking about. If you were putting it back together with the same gaskets, now is your chance to not do that. Good luck, tell us how it goes.

Oh in another thread someone suggested using a small manual oiler/oil pump to do this if you don't want to wait for the syringes.

 

Just tried this method. Could NOT get any fluid to push thru. Do I need to tie the brake lever to the grip to open the MC valve?

 

I don't think so but I can't say for sure right now because it's been a while since I did it. I'm mostly sure you don't have to; I don't remember doing it.

If the M/C cover is off, the bleeder is open, and you're trying to push fluid into it and it's going nowhere, then something else is going on here that is currently unknown. Can you backtrack a bit for us and maybe we can figure it out?

What all have you done so far in terms of taking things apart? Did any of the banjo bolt connections come apart? Did you rebuild the M/C and/or the calipers? Did you do new pads yet? Did you push the caliper pots back into their bores? Did you remember to clean them well before you did it?

Describe what happens when fluid doesn't push through. Does it seem like it's taking forever but it's basically working, or do you mean you can't push any in whatsoever?

 

The only thing I did was drain the MC with a syringe, remove the banjo bolts, pull the 2 12-point 10mm bolts and slide the calipers off the discs. Carried them 10 feet away and sat them in a tub on my bench. Small containers were attached to the ends of the brake lines to catch the residual dripping fluid. Today I reattached the calipers to the bike and then the lines to the calipers with the original banjo bolts. I didn't rebuild anything or dismantle any further than what is stated here.

When trying to reverse flush it does not go at all. Not a little, not slowly, but not one single little drop goes in.

I just pulled the left caliper off the bike again to inspect. I also was able to blow into the brake line and saw air coming out at the MC. I also made sure the pistons were able to be moved and went ahead and pushed them all the way in. I am in the process to getting the right one off now to do the same thing.

 

Everyone, thank you all for the advice and what-not. I figured it out and it turns out I'm an idiot. Was in a hurry to get this bike on the road (terrible idea) and overlooked the obvious.

Having easily bleed the rear brake last week I set about the fronts in the same manner. Using my trusty 13mm to try to do the job I was completely overlooking the fact that I was simply just loosening the banjo bolt, NOT THE BLEEDER VALVE. Figured out how to actually do it right and brakes were bleed with the Might-Vac in less than 10 minutes. Sometimes it truly is the simple 'ish that gets us, I guess.

 

When you mentioned gaskets on the bleeder I did wonder but I thought no you wouldn't get the two mixed up.

Well done for the admission. Glad you got it sorted.

Copper crush washer become work hardened. They can be annealed but for the cost it is more effective to use new.

 

Right on man, glad you got it sorted and shared what happened, respect for that. I know what it's like to make that sort of mistake, one that's more about how you're working than anything else. In the last few years I've had to do things under time pressure and other stresses that ultimately made me screw up things that I would not normally have made.