I'm bleeding my breaks and changing the master cylinder,the master didn't fit in t my vice so I couldn't bleed it!. So how do I bleed it now it's on the truck?.

One guy pumps and holds the pedal while one guy bleeds each wheel repeat and repeat until you have a firm pedal . Keep topping off the master as you go or you will need to start over. That’s the quickest way I know of.

Also start with the left front/right front/left rear and right rear last

I'd make short looped brakes lines that dump back in to respective reservoirs and bleed it into.itself to get air out.
Or you're going to use a lot of fluid.

Didn't new master come with short plastic lines?

First bleed it at the master cylinder. Bleed the flare nut lines connected to the master.

Then bleed it at the wheels.

I find it works better to open all the lines and let them drip for a few minutes, keeping the master full. Then close all the lines, put the cap on the master, get someone to pump the brakes, hold the pedal down once it's stiff, open the bleeder, let the pedal go to the floor, hold the pedal down until you close the bleeder, and repeat until no air comes out of the line. Top off the master and repeat for all 4 wheels.

This.

Very seldom will you need to bleed at the wheel if you bleed at the lines.

it sure helps to have a friend, kid , neighbor or a vacuum bleeder

vacuum bleader is less frustrating than training kids the first time but all 3 of mine have been the brake pedal operator at some point bleeding brakes

so have a beer and train a kid , good life skill

vacuum bleader put on farthest bleader and keep filling the reservoir till she runs clear , with no bubbles , then repeat each closer wheel

Bleeding a new master cyl is a bit more involved than bleeding brakes after a routine brake job.
Not more involved, just a LOT more pumping.
I.prefer to bench bleed before installation but have done it both ways.

Thanks for the answers.

I'll disagree, if you don't start pumping and bleeding thru the wheels and bleeds at the lines going into the master, done in no time.

Actually, just crack those lines open and wait a spell and sometimes you don't even need to pump at all. Air doesn't go down the lines unless you push it there.

C-clamp

Bench bleed, then all four corners starting at the furthest from to closest.

And if you ain't got a helper that can tolerate being yelled at get a long length of clear hose and mason jar.

Now I ran into another problem. I can bleed both fronts and driver back,nothing coming out back left! and the master in almost full. What do you think the problems at?

Take the bleeder screw all the way out. Check to see if the hole in the center of it is not plugged. If needs it , new bleeder screws are cheap-ish.

If it is not that , check the valve/splitter where it splits into two lines.

OK thanks

Lemme redefine that a bit , there is a 1/8" or so hole that the brake fluid drains from but some bleeders have tiny 1/32" holes at a 90° angle to the 1/8" hole. That is were it would be plugged.

If not bleeder screw check function. That caliper/cylinder should function close open with operation of the pedal. If no function you have no fluid moving. Trace brake lines looking for stoppage or kink. Check splitters. Moving upstream as you go.
If you have one side but not the other then it should be somewhere between the wheel and the splitter.

X2