whoops, to bleed the brakes there is a rubber capped nipple around the back of the hub, you take like a 12mm socket and open that up and let air bubbles come out, then you close it and have someone pump the brakes till theyre hard....

then open it while they apply firm and even pressure.

then close it

let them pump the brakes


open it and let the bubbles out

continue till the pedal is firm and no air releases, repeat for each wheel you worked on.

btw, the reason is air is highly compressable while fluid is nearly impossible to compress.