Join Date: Sep 2016
Location: Lethbridge, Alberta
Sounds like you've covered all the likely spots where air could be trapped.
Your problem is likely with the master cylinder. Likely will have to be rebuilt again. Don't know if the bore is bad but if so you might have to hone it.
Three things tend to happen with master cylinders on older bikes. The small hole in the bottom of the master cylinder gets plugged, the piston in the MC gets overtravelled and damages the rubber seal at the front of the piston, and the piston in the caliper sticks.
My gues is that you've overtravelled the MC piston. So get another kit, tape a 1/2" socket on the handlebar, between the throtle grip and the brake lever ( this prevents the lever from going right to the grip which damages the seal on the piston ). Install the kit, fill the reservoir with proper brake fluid, install new crush washers at all banjo bolts ( if they've been disturbed ). Don't touch the front brake lever. Bleed at bleed valve at caliper, using a vacuum bleeder ( sounds like you have one ). Once you get all the air out of the system, then go to the front brake lever and see if you have pressure. Hold a rag over the master cylinder, and look for a squirt of brake fluid when you pull the lever, that tells you that the small bleed hole in the MC is working properly. Or just go ahead and put a known good MC on the bike. Sometimes that ends up being the onkly thing that works. That's what I ended doing in one case that I couldn't get the old MC to work properly.