If the brakes master cylinder is installed without bench bleeding it first?

you have air in your system .bleed your system from back to front and for pulling to the left you have LEFT caliper pistons is sticking went you push on the brakes the front left brake grab first will pull to the left

If it came with a bleed kit, it can be bled on the vehicle after mounting. Just hook up the hoses as you would if bench bleeding and use the brake pedal to bleed the air from the cylinder. Just make sure the reservoir does not empty out or you will introduce air back into the master cylinder.

Your pedal will not come up until you bleed the entire system. Start with the rear passenger tire, then rear driver tire, then front passenger tire, then front driver tire. The best way to do this is with a power bleeder. They don't cost much money and some models will allow you to do this yourself instead of having someone help you.

If your car pulls hard to the left on hard, quick stops, your front driver brake is probably grabbing a lot harder than the passenger side. If you did not replace the brake pads and turn the rotors while doing this work, the problem will probably persist.

NO!!!!! It will absolutely not. if you are pulling to the left you need to check your right brake caliper (the thing that holds the brake pads on). You can usually just jack it up, take off the wheel, remove one blot, and swing it out after you loosen the other one. If everything looks fine then you may need a new hose, but by no means does a master cylinder cause pulling what so ever. it applies pressure equally and unless you have done some heavy cutting and welding to it then there is no way that it will cause a pull. Also if you replace something involving your brakes bleeding is easy as pie contrary to popular belief. simply take the bleeder cap off one caliper and pump the brakes a few times. Repeat that on all of the calipers. Hope this helps.