Hey everyone, hopefully some of you can shed some light on this problem. I bought this 1983 Accord for my winter beater. At the time the brake system seemed solid. Pads still had plenty of wear left to go, no fluid leaks, caliper pins and pistons were all moving freely.

Just this past couple of weeks I have been having issues with a my brake pedal feeling hard. Upon start up of the vehicle the brake pedal depresses and feels like it should. After about 10-15 minutes of driving the brake pedal will start to stiffen up and have pretty much no movement, however the brakes are still very responsive and have good stopping power. Second part to the problem is this entire time the brake pedal stiffens up my brakes are being slightly applied causing a large amount of drag on the vehicle. The rotors are slightly warped and with the applied brakes I get a pretty nasty shake in the steering wheel. It's getting to dangerous to drive around the city now.

My first guess was a bad power booster but I have looked into threads about bad power brake boosters and most people say the pedal will feel hard and have no stopping power. I was just curious to see if anyone had some information on this matter, thanks.