Having to pump brakes to get a good pedal is a symptom of incorrect brake adjustment. You're having to move more fluid than one pedal push can accomplish to get the brake shoes into contact with the drums. A hydrovac works just like any other booster- - - -you're using vacuum against a big piston to make your leg stronger. If the engine speeds up when you push the brake pedal, you've got a vacuum leak. If the engine runs rough and a cloud of choking white smoke comes from the tailpipe when you step on the brakes, you've got a brake fluid leak into the vacuum chamber of the hydrovac.
Fix the leaky wheel cylinders, replace any fluid-soaked brake linings, and adjust the brake shoes properly for minimum clearance from the drums- - - -you'll probably have good brakes without having to mess with the master cylinder or the hydrovac. Be sure to inspect the steel and rubber brake lines for leaks, rust, or damage. There's nothing that increases your pucker factor worse than blowing out a brake line unexpectedly!
Jerry
