Andrew Hajnik

Hey yall im new to the whole forum thing although i have been on here hundreds of times reading.. but anyways i have an '86 f150 4x4 and was replacing the ball joints and well hell im this far thought i should redo u joints while im at it and was about to press out the drivers side shaft until i noticed a crack near the top of the hole where the u joint goes.. My question is would there be a way to fix it? (ex. welding) or should i just replace it?
Also would an '87-'91 front axle shafts fit without any problems??