Q: My car brakes are spongy

When replacing a master cylinder, it should be "bench bled" before installing it in the vehicle. This involves filling the reservoir with fluid, connecting rubber hoses to the brake line ports and placing the other end in the fluid reservoir, then operating the master cylinder piston. This make sure all the air is out of the master cylinder itself before installing it. Since you have already installed it, you should try bleeding fluid at the master cylinder, then work your way around the vehicle and bleed the system from each wheel again. If you do not have a bleeder, have a friend assist you. Have your friend pump the brake pedal 2 or 3 times, then hold the pedal. Crack a brake line loose at the master cylinder, making sure your helper does not press the brake pedal completely to the floor as you open the brake line. I usually place my other foot under the brake pedal when foot-bleeding. Repeat this 2-3 times with each brake line at the master cylinder, then re-bleed the system from each wheel, making sure to start at the wheel furthest from the master cylinder and finishing at the closest. If this does not help, then try removing the master cylinder and bench bleeding it, or have a certified technician look into the spongy brakes for you.