Breaks (soft/low)

ok, just had to change out the break tube on the passenger side of my 97 ford explorer, and the break light is now off. I thought this was then end of my troubles, but now the breaks are really soft and I am not sure what that means. Could it be air in the hydrolic system? And if so would I just drain the breaks and replace the fluid as if I was doing a break job on my car? Any advice would be great!

You need to bleed the brake system plus the lines at the master cylinder,