IF the Master Cyl runs dry, you need to bleed it first, then the ABS module. it IS possible to do it without a scan tool, it's just time consuming. A pressure pot is your friend for this, but most folks don't have those on hand
Replace everything behind the ABS module first, then bleed those, wait about 15min, then bleed again. THEN break the line between the master and the ABS module.
The idea here is to NOT introduce air into the ABS module at anytime, if you do, THEN you have to cycle the solenoids to work the air out ( this is what the scan tool does if it has that capability )
when you replace the line between, break the connection at the master first, use a plug of have a buddy hold his finger over the open port of the master ( don't let it go dry is the point here, fill the resvoir and replace the cap before you break any lines ( creates a light vacuum in the res, slows down the fluid loss )
be sure you disconnect the ABS end of the line last, and that everything down stream is closed off.
connect to the master first, after it is all routed where you want it, then on the ABS module end, place your thumb over the end of the line sealing it ( rubber gloves are good here ) have your helper slowly work the master DO NOT Let your thumb off the end, when the pedal returns, it draws fluid into the master cyl bore because of the suction created by your thumb over the end, it should only take a few strokes of the pedal to get clean fluid with no air.
Then connect the line to the ABS module but leave it loose, slowly work the pedal while tightening, you want fluid to come out as you are tightening, once tight, cycle the pedal a few times and and bleed there again.
then check the pedal. wait a few minutes, then try it again ( you're waiting for the air to settle at the highest point, to which you will push it out when you bleed )
It's time consuming, it's messy, but it works.
I've done several GM vehicles and couple Hondas in this same manner
