If you find that a wheel stud snapped in your Ford Focus, you need to replace it as soon as possible. When you replace your wheel stud, you protect the other studs from stress and prevent further damage. It takes a little knowledge, the right tools and some brute strength. Plan on a little more than an hour of time.
Buy a new stud. Make sure you purchase the right size. If you're not sure what size to get, wait until you remove the stud and take it with you to the store.
Check the area of the spare tire in the trunk for the jack and the jack tools since you'll need to raise the car to replace the wheel stud on your Focus. Be sure to block the tire diagonal to the jack.
Use the jack to raise the Focus. Remove the wheel Take off the caliper and either hang it by a mechanics wire or lay it up so it doesn't dangle by the brake line. Remove the rotor. If you're working on back wheels, you have to remove the emergency brake clip first. You could have drum brakes in the rear. If they're drum brakes, remove the drum.
Hunt for an opening behind the hub that allows you to remove the stud. Line the stud up with the hole. You may have to take off the hub and put it in a vise if you can't drive it out the back.
Hit the stud with a mallet and drive it out the back of the hub. Push another stud into the opening. This is tough work, but you only need to push it far enough to thread on a wheel bolt.
Put on a wheel bolt and begin to tighten it. As you do, the stud starts to pull through. Add more bolts as necessary until you seat the stud. Check in the back of the hub. When the head is flush with the stud, you seated it.
Remove the extra bolts and reassemble the parts that you took off to replace the wheel stud on the Ford Focus. Put the wheel back on the vehicle and tighten down the wheel nuts.