Over the years, Many, Many times the problem with uneven braking has been the flex hose from the wheel cyl. to the frame. They tend to deteriorate inside and a piece of hose dangles down acting as a 1 way valve. Hose seems OK, may allow fluid to ether WC, but not back, leaving the brake applied. Or, blocking some/all the flow to the WC preventing it from working properly.
I have had a mityvac for probably 50 years, plus a newer one made of metal. A great tool for bleeding alone. I would pour the brake fluid in the master cyl. and then just stick the BF container into the reservoir upside down to ensure enough fluid.
Won't run over, but won't run out of fluid.
There are also tools to pressure bleed, applying pressure to the MC and going around and opening valves into containers. This is helpful if doing it alone. Don't need a 13 year old on the pedal.
Ray in sunny Mena, 60's tomorrow but then it turns to crap with more snow on the way.
Nice here as it only last a day...