I had this issue too. but now you cannot get the bushing from ford and the arm is like 40 bucks used. but you can fix pretty easy buy making a new bushing. next to impossible to find it.
1. get Dorman ford wiper linkage bushing from adv. auto - Part No. 49451
2. it is a little bigger then the hole in the linkage arm. so you need to shave it down a bit, but leave it a little bigger
3. put the linkage in a vice to hold it and using a grill lighter or plummer's touch, heat up the bushing a little (don't burn it), just so it starts to soften, and work it into the arm hole. use extra to melt opp side to hold in place. Also, make sure to put into the hole in the correct direction that it goes onto the wiper motor with.
4. rough up the outside plastic bushing and use epoxy like JB cold weld to cover the whole outside of the bushing and lap it around the arm - basically in case it. but be sure not to get any in the whole where wiper motor ball goes.
5. paint the outside so the sun will not dry out the bushing like the orig. one
6. put some grease in the ball whole.
7. mark the position of the ball joint to the wiper - how it is mounted. or skip if you can just pop on when re-installing - I had issues trying to do this, so I took off then installed
8. pop the ball into bushing, then when installing wiper motor, reattach the ball bracket to the motor - lining up the mark you made when you took off.
9. finish the motor install and test to make sure the wipers start/stop where they should. if not, you will have to take apart and adjust the ball bracket a bit until it is correct.
this worked for me - good luck