OK, i was just checking fluids and such and i noticed that my master cylinder was a little low. btw, its a 65 with a single piston master w/ 4wheel drum brakes. so i added a little dot 3 to top it off. went for a nice drive. well, when i got home the brake lights were stuck on (i have the 64.5 pressure switch on the master cylinder for brake lights). so i got in the car and tried pumping the brakes. the pedal was hard as a rock and didnt move as easily as usual, but the brakes were still working ok. so i then slightly unscrewed the brake light switch just enough to let a little fluid out and then re tightened it. now the lights are off and the pedal is back to normal. what is going on here, why would this happen? until i change to a dual setup, i dont need any brake problems!!! also, i just changed the rear drums a few days ago, i dont know if this means anything... so its either something to do with topping off the master or the new rear drums. could the rears be dragging and causing the fluid to boil or something making too much pressure in the lines. im confused.