Here are the upcoming Daydreams. These lists will be updated as new ideas and repairs are required. When an item is complete it will be lined out and linked to the post describing the project.
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Mechanical Daydream 
In the theory of automotive brake systems. What you have is great. But we get how the pressure from hydraulics move the pads. I would like to know what is used to release the pads from the rotors so the brakes don’t drag and burn up after stopping..
The brake pads do constantly ride very lightly on the rotors. Without actual pressure on the pads they will generate very little heat (much less than can be removed by the constant stream of cooling air).
3 things can happen in this instance, depending on the setup. number 1, the ‘stream’ of air from the rotating disc keeps the pads off the surface.
number 2, a spring clip or plate deflects when on the brake and pulls the pad back when the brake is released
number 3 the rubber seal has roll back. the size, shape, number and compound dictate how much. like a spring, the rubber seal stretches before allowing the piston to slide. this stretch is elastic and springs the piston back when the brake is released.
typically a race car caliper would rely on roll back more than a road car, even to the point where different compounds of seal can be purchased to ‘tune’ the effect.
Other things helping to move the pads away from the rotor upon releasing the brake pedal include distortion from heat in the rotor knocking the pads back, deflection in the spindle and play in wheel bearings. An abnormal amount of any of this will show up as excessive travel in the brake pedal.