The spark plug threads in your 5.4 Ford engine can be stripped in a number of ways. A blowout can rip them smooth when the spark plug is thrown from the engine. Over-tightening a new spark plug or neglecting to remove an old set of spark plugs for too long can damage them. No matter how it happened, if your spark plug threads are stripped, your Ford isn't going anywhere. While this kind of damage can be fixed, you run the risk of ruining your engine trying to retap the threads, so this is not a task recommended for a novice do-it-yourself mechanic.
Slide the counterbore into the black metal insert that came with your kit and tighten it, then affix the insert to a ratchet as if it were a socket. Spray the counterbore's head with WD-40.
Slide your counterbore into the stripped spark plug hole, then and tighten it until the counterbore spins freely.
Pull your counterbore out of the insert, then put the reamer into its place. Once the reamer is tightened down, lubricate its head with WD-40.
Slide the reamer into the stripped spark plug hole, then ratchet it down until it spins freely.
Take the reamer out of the insert and replace it with the tap. Lubricate the tap with WD-40.
Slide the tap into the stripped spark plug hole, then ratchet it down until it spins freely.
Remove any shavings from the hole. A shop vacuum with a hose attachment is good for this. Afterward, spray it with brake cleaner.
Take the tap out of the insert and replace it with the setting tool.
Put the cap screw into the setting tool, then tighten it into place with the provided allen wrench. Once it's tight, coat the outside of the cap screw with the locktite from the kit.
Ratchet the setting tool into the spark plug hole until the flange of the cap screw is seated on the bottom of the spark plug hole.
Use the allen wrench to loose the cap screw. Once it's loose enough, you will be able to pull the setting tool out.
Take the setting tool off the insert and tighten the driver into place. Coat it with the provided lubricant.
Tighten the driver into the tap screw until it looses up. This will take roughly 10 turns of the driver.
Pull the driver out of the spark plug hole. Once the locktite dries, the threads of your 5.4 engine's spark plug holes are repaired.
