They're called brake bosses, and you use then as attachment points for a certain type of rim brake.
Yes, that is what the bleeder screw is for
No.
Bleeder screw for clutch is at the slave cylinder, on the bell housing of the Transmission. The bleeder for the brakes is on the calipers, and on the backing plate of the rear drum brakes
Next to the coolant reservoir... black hose sticking forward with a plastic screw in it...
what is a screw
vice-grips
Undo the Allen screw in the center and it should come right off.
Yes, as long as you can access the bleeder screw.
To screw and unscrew things?
A screw may be used to fasten things together, or to wedge things apart.
something is loose like a screw needs tightening get it fixed before it brakes
screw it in turn the piston clockwise and screw it in , only for rear brakes