Just got my truck running (YES!

!!) and put some brake fluid in, to test her around the house. Tried to stop her but no luck

. Pump on the brakes a couple of times and could feel some pressure but no enough. So pulled her back into the garage and checked my brake fluid , NONE. So I pulled the brakes apart and notice the wheel cylinder is missing what looks like a plug on one side. Could this be my problem. Its a 1953 GMC 3/4