Brake bench bleeder kit

TrailBeast said
Bottoming the piston is not required to bleed it.
Otherwise you couldn't bleed a used master due to it not being recommended to make the piston travel more than it's normal working stroke.
This is because making one travel more than it normally does when driving can kick up junk settled in the bore where the piston doesn't normally travel causing piston seal failure.

When I bleed a new master I put it on the vehicle with a towel under it and the fittings connected.
Then pump the pedal a few times to get fluid moving, and then crack each fitting and use short light strokes (like if you were just trying to get the brake lights to come on.)
Short light strokes doesn't give air a chance to suck back in.

Try it some time.
I am a big proponent of being able to do things without help and learned that this works. (probably before you were born):D
It even works when bleeding at the wheels believe it or not.

Bench bleeding is usually only necessary with a brand new master cylinder. Even with a complete fluid change, you'll never get the master cylinder completely dry like they are when they're new.

But, when the ARE new, a bench bleed may be required because you might not get enough piston travel in the car to eliminate all the little air pockets in the master cylinder. Sometimes bleeding in the car works fine, sometimes you'll chase your tail for days and still have air pockets in the master. Bench bleeding is recommended with a new master for that exact reason.