what do they mean by bench bleeding the master cylinder, can someone explain or give me a link to this

 

It's just as it's called, u bleed the air out of the master cylinder at a bench, clamped in a vise. Use short pieces of tubing attached like the brake lines would and bent around to go back into the reservoir.

 

It's just as easy to do the equivalent with the MC on the car with a MC bleed kit available at your local parts store for about $2. If you do this, buy 2 kits and make sure it's a metric kit.

It's just a simple collection of little plastic nipples that have threaded ends. The kit comes with one each of a few different sizes. You need 2 of the 10x1's. Plug them into the brass connector that sits beside the MC (if we are talking about a [3], otherwise I have no idea) and run some hose from the nipple ends back into the MC resevoir, making sure the ends are immersed in fluid. Pump the brake pedal until you see no air.

Don't attemp to bleed the entire system via the calipers after changing the MC.

 

Yes. I also do this on the car. I also have a 12 oz drink bottle that I use when bleeding wheel cylinders and calipers using a piece of vac hose submersed in the fluid. Had to come up with this idea cause I'm always having to do things by myself.