i think that video is accurate. I never had too much luck with bench bleeding masters. then again, i've only done it twice and i was making such a mess the second time that i gave up and installed it and bled the whole system.
It often take me multiple bleeds and some light use to get the brake system fully bled when it has been as disassembled as yours.

 

I thought about taking the MC apart when I had it off but I guess I was banking on the leaks being the culprit. I might go ahead and take my old master apart though since it's sitting idle. I think ken125's probably right that my original MC might have had a sticky valve. That's the only thing that seems to explain how it simply stopped working while up on jackstands. If I'd known then what I know now I would have tapped it with a hammer. It seems unlikely that the new MC straight from a performance shop would have the same check valve problem, but I'm running out of explanations.

 

More leaks after leaving it pressurized all night. Both banjo bolts are leaking, one more than the other. Even the three banjo bolts on top of the ABS unit had gotten a little moist.

I turned them all 1/8 and will give them another day.

Maybe I need new banjo bolts. Given all the trouble with the oem setup though I'm considering whether switching to flex line with adapters might make sense.

 

You likely are completely aware of this, but...

All surfaces where the crush washers seat must be hermetically clean and have NO imperfections. Any scratches, bumps, or pitting is an invitation for leaks.

Also, in my experience, in any installation where any of the components (banjo bolt, banjo, female component) are aluminum, aluminum crush washers work better than copper (aluminum is usually softer and more compliant), and have less likelihood of leaking.

 

Yeah, I sanded the banjo edges with 400 grit until they were perfectly shiny and then sprayed with brake cleaner, I had the choice between aluminum and "soft" copper crushers and I might have picked the wrong curtain. If I have to take it all apart again to switch to aluminum washers I'm just going to go ahead and replace the banjos with new ones. Live and learn. Good thing I'm not charging myself an hourly rate.

 

I use copper crush washers only on all-steel banjo assemblies or steel oil pan plugs, etc.

 

Mazda shows 9956-21-000, which is copper

for 9956-21-000
99 = hardware item
56 = crush washer
2 = Copper, 4 is Aluminum
10 = is the ID, 10mm. Mazda has sizes from like 6mm to like 23?
00 = not used for this part type

so 9956-41-000 is a 10mm ID washer in Aluminum, 9956-21-800 is copper and 18mm, etc etc

 

From the Atkins site

 

The extra 1/8 turn last night helped. The banjos on the MC are bone dry now as well as the center ABS banjo. The outside two ABS banjos are still moist so I gave them each another 1/8 turn. For purposes of documentation, my technique is basically to rub a black nitrile gloved finger all over the fittings, including the backside and then tracing down the brake line. Any moisture shows up right away on the glove. Then I'll tighten. Then dab it all dry with a Q-tip and run the finger all over to make sure it's dry. Then let it sit overnight and check again.

 

which is wrong, and they probably don't buy this from Mazda.

 

On the subject of crush washers I have found it is best to order them from a legitimate supplier like McMaster-Carr. "Crush" washers from Amazon, eBay, and sometimes auto parts stores are very hard, almost like they are a mix of cheaper metals with a low copper content just for color. A soft copper washer should bend or mar easily.
Another option is to smooth and then anneal original washers which is pretty easy. Block sand them and then heat them red hot (evenly) before quenching them in water.

 

I usually order crush washers from Ray Crowe or Mazda Motorsports. I don't trust Atkins at all - no offense to anyone who is a happy customer.

 

I don't own a blow torch. I tried to anneal a washer with a propane torch and ended up melting it.

Today I thought I had it all dry. Everything looked good then suddenly I noticed that my gloved thumb was covered in brake fluid. What? Where? I felt around and discovered that the bottom of the MC was coated in brake fluid. I dried it all off and then waited for the leak to show. Turns out this time it was leaking out from the bottom of the inside banjo washer, with the fluid being drawn underneath the MC instead of dripping. Also one of the fittings is now weeping a bit (I guess that's how pressure works. If you tighten up somewhere else then it will find the next easiest path.)

Another 1/8 turn and will check tomorrow, but I'm just about ready to swap in fresh hardware. I've grown to hate the oem setup with those little finicky hard lines and bracket. I'm thinking about replacing with stainless flex or copper/nickel line plus new fittings/adapters.

 

The problem finally is resolved. It was indeed leaks. Those small weeps were enough to prevent proper bleeding. Thanks to all for keeping me on the straight and narrow.

I simply could not get the original banjo fittings to stop leaking and so I ultimately ended up having these new lines fabricated (stainless with poly coating). They are both 30cm long and have standar 10mm banjo fittings on one end and 10mm SAE seat on the other end. I got rid of those pesky little hard lines and the bracket that holds them. Tightening these up is then a pretty simple double-wrench action. I couldn't find these off-the-shelf anywhere so had them fabricated by "Brake Parts STOP" (https://www.brakematerialsandparts.c...om-brake-hoses). This guy was great. I told him what I needed and he assembled them without crimping and sent photos so I could confirm that they looked right. $49 each and they were in the mail an hour after I contacted him.

Note that I also used new banjo bolts. The OEM banjos (even the replacements I got from chips motorsports) have a lip on the head that causes the crush washers to fold into an extreme shape. These standard banjo bolts are flat. New copper washers worked just fine with the new banjos. I didn't torque them to anything specific, just snugged them up good. I suspect that softer aluminum washers might have a better chance of conforming to the extreme shape required by the originals as mentioned in some posts.

Everything is bone dry now and the brakes are back to normal. It's real easy to get in your head when the brakes aren't working and you're trying to understand pedal play. For what it's worth, with the 929 cylinder now there's definitely some play in the pedal before braking starts, and then braking occurs over a small range of motion, and it does so without excessive stiffness. It feels completely normal, just like my modern cars, but it's certainly hard to quantify normal when it's not right in front of you.

The other good news is that with proper braking re-established I was finally able to ge tup to speed and confirm that my restoration of sequential turbos was successful. This was my first time experiencing factory-smooth acceleration instead of the hammer jam in the back that I was getting from non-sequentials.