[lockit4u]

Three things will make a pedal go to the floor air in line or a fluid leak or bad master any other parts like booster or pump would not cause a pedal to go to floor. sounds like a bad brake master cly. it cost new a autozone 108.00 buck plus a 4 buck bottle of brake fliud. you can do it your self . done in less then a hour!!!!!! or 100 dollars labor to install it . 32 year master mechanic here. In 32 years never seen a brake booster go bad.👨‍🔧

 

[lockit4u]

See if the booster hold vacuum if it does then its good . When you say pedal is 100% do you mean soft or hard?

 

[lockit4u]

The pedal was going straight to the floor, it was braking, but seemingly with no help from the hydraulic system.

If pedal going to floor replace only brake master cylinder and bled brakes DONE. BOOSTER IS FINE! Parts are 106 dollars plus a bottle of brake fluid.
your master when out . when they go out they just stop working.

 

[lockit4u]

So what was the fix? Don't leave us hanging.