Hi everyone, I'm new to the forum and I've just purchased my first X1/9, a 1974 with 54k miles. It seems to be in exceptional shape with zero rust. However, the brake pedal was totally flat when I bought it. I assumed the master cylinder was at fault as the car had been sitting for a couple years and replaced it as soon as I got the car home. I had trouble getting pressure on the front calipers, and I eventually had to take the caliper off and use a guitar string to break the filth loose from inside the line. I bled all the rust and filth from the system until the fluid ran clear, and I have since replaced the pads, but the brakes are still extremely weak. I've found that the right caliper is locking up under intense braking, and I'm trying to figure out what I should do next. Any help is appreciated.