Material cost: ~$10
Difficulty: 2 (very simple to do, you just might need some body strength)
Tools needed: Pliers, cutters of some sort (diagonal, scissors, etc), tire plug kit
So you likely discovered you had a flat tire at a very inopportune time. You hit the closest gas station, fill it up with air to get where you need to go, but don't want to drop it off at some shady tire shop and have them d!ck around with your car and tell you you need 4 new tires, among other things. What do you do? Plug that mother yourself.
Inspect the visible area of the bad tire. If you're lucky (which you probably aren't, because after all... you just got a fuggin flat tire) the foreign object will be visible and you won't even have to jack the car up. In the above picture I sprayed some soapy water on a suspect object to check for a slow leak, but it turned out it wasn't the culprit... so up goes the wheel/tire.
Chock a wheel that will be staying on the ground and lift the suspect wheel. Take the E-brake off or put the vehicle in neutral in order to spin the wheel around until you can find the object.
'yarrrr.... thar she blows. Get it in a good location and put the E-brake back on or put the vehicle in park/gear so it doesn't rotate around on you while you man-handle it.
Get a trusty set of pliers out and pull the culprit out of your tire. Discard it, burn it, piss on the ashes, but make sure you don't just drop it on the floor and run it back over after you've finished the repair.
Bust out the repair kit. It should have a T-handle dagger type looking thing that is rough around the shank. You're going to have to shove this into the hole that was created when the nail/object went into your tire. Depending on the size of whatever was in your tire, this could be difficult and require some upper body strength. If you had a really small hole (like from a finish nail or something), you might want to drill it out slightly bigger before trying to plunge this thing in there.
Once its in, work it around a bit to enlarge the hole and clean the inner surface.
Pull it out and locate the other T-hande that came in your kit. It sort of looks like a sewing needle, except the eye has a slot in it. Insert a plug from the kit into the eye of the "needle". Make sure the plug is rotated correctly so it goes in without too much difficulty (and will come out without too much difficulty).
Coat the plug in the rubber cement compound that came with the kit.
Next, plunge that mofo into your tire so about 2/3's of the plug is inserted into the hole. DO NOT rotate the handle.
Pull the T-handle backwards again without rotating. The plug should slip through the slit in the "needle" and stay in the tire.
Clean off the plug inserter tool so you can use it again in the future.
Now you'll notice there's some plug sticking out from the surface of your tire. Trim that back as far as possible with a pair of cutters.
Mine was in a pretty crappy spot (inside the groove), so I couldn't get to ALL of it.
Are you done? Yeah, pretty much, but Hubris hath slain many a Greek hero, so before you let the car down and call it a day, put some air in the tire (we'll say 30 psi) and spray the area with soapy water to check for air leaks. It might bubble up when you first spray it, but as long as those bubbles don't increase in size, you're ok.
That's it! Let the car down and inflate to your manufacturer's recommended pressure (usually printed on the inside of your door jamb). Don't know what it is? 32 PSI is a pretty safe bet.
