Or put a brake pipe clamp on the rear flexi pipe, if rubber and try brakes with engine running. The rear brake shoes are best adjusted manually as the auto adjusters are not brilliant. The shoes should be dragging slightly when turning drum when correctly adjusted.
BTW the new master cylinder is highly recommended as old ones are usually scored, or corroded down the bore.
Good luck.
It's old technology i'm affraid.
1979 TR7V8 FHC.
DJE 4.6 Block and Heads.
22 years of tinkering and tuning......So far!
Now available in red.