Hello Michael,
I Believe you will need to remove the brake shoes at the very least. You can hone and clean up the cylinder in place. The actual cylinder size is in inches. The rubber seal cups and rubber covers can be purchased at NAPA or most auto stores for around $5 a side, after you figure out the diameter. Save the original hard parts to clean up and re-use. Fresh brake hoses are always a good investment if they are old.