Brake

Adjust the rear brake shoes !!!

Vacuum bleed off is normal after the vacuum source is removed, what vacuum is left is depleted after 1 or 2 pumps of the pedal. Try pressing the e-brake, put the pick up in gear, if she won't move easily whilst applying gas, then you're rear brakes are probably adjusted correctly. Unless, you mean, the pedal goes to the floor when the engine is running, in that case, you've got air in your brake lines. ABS brakes bring a whole new form of fun n pleasure to brake bleeding. Any service manual will instruct you in how to properly bleed ABS, whether 2 or 4 wheel ABS.

I changed my brake master cylinder but its still a spongy fluid peddle