Ford Focus Forum : “Popping sound in steering”

Sounds like you may have a bad tie rod end or other front suspension/steering rack related issue.  I would have this checked out ASAP.  Don't want to drive it too much until you can verify the problem.

Does it do it on bumpy roads? Sway bar end links are notorious for doing the popping sound. If it just started doing it and the car feels fine in turns then it should be ok to drive but have it replaced asap. They ball joint can seprate from the end link and then your car will feel *very* loose.

it could be something as simple as the wheel arch lining catching on the tires when you go to full lock. this happened on my friends focus but it was a s reg (1998 i think)