Did it work? I know that manual brakes can be more finicky than power brakes and the stopping power requires more leg power. Here is a Website for Diags if it did not.
http://www.classicperform.com/TechBo...oubleshoot.htm
I did notice in your post you questioned the Proportioning Valve. Which is why I asked you to rebleed the Front Left for the pulling issue.
The function of the proportioning valve is to limit pressure to the rear brakes relative to pedal force, especially when high pressure is required to apply the front disc. This prevents the rear wheels from locking up as weight is shifted forward during braking. Proportioning Valves are generally located in the brake line to the rear brakes and sometimes are incorporated into the master cylinder. They are available as either preset or adjustable valves. Note that adjustable proportioning valves are not DOT approved for street driving and should only be used for racing applications!
