So Fix it

Park the car on a level surface and set the parking brake.

Place wheel chocks behind the rear wheels.

Raise the car with an automobile jack and place a jack stand under the car at the frame rail. Position the jack stand as close as possible to the frame.

Remove the bolts from the front and back end of the catalytic converter with the proper size socket and a ratchet.

Remove the catalytic converter from the exhaust system by twisting it and tapping the ends with a rubber mallet.

Install the new catalytic converter in place of the old one and secure it with the bolts hand-tight.

Tighten all of the bolts with the proper size socket and ratchet.

Remove the jack stand and lower the car to the ground with the jack.

Use your spare keys until you can obtain new keys for your car.

Call your local car dealerships service department to order a new key. If you have a late model car that uses a transponder key embedded with a computer chip to match that of your vehicle you will need to purchase a new key from an authorized vehicle dealership. Expect to pay a large fee for a new transponder key, as they run anywhere from $150 to $250 per key, depending on the make and model of your vehicle.

Provide the vehicle service department with the vehicle identification number of your car. The location of the VIN depends on the type of car you drive. It could be on your drivers side windshield, viewable from outside of your car or it could be located on the door panel of the drivers side. VINs are always located on purchase paperwork, insurance information and registration forms. The VIN contains the key code for your specific vehicle, which allows the key maker to know exactly how to cut your new key.

Pick up your replacement key and test it on your vehicle.

Wait for the engine to cool down so the exhaust pipe is cool enough to touch. Place your hand near the pipe to gauge how hot it is before actually touching it, or wrap a thick rag around your hand.

If part of the pipe is about to fall off, remove the hanging part by bending and twisting it until it breaks free. You neednt reattach it, since you must have it replaced or welded on at a muffler shop anyway.

If you cant break off the hanging pipe, untwist a wire coat hanger or use some mechanics wire (available at an auto-parts store). Wrap one end around the hanging pipe and fasten the other end to the underside of the car. Do not wrap the wire around the drive shaft or anywhere where it risks becoming tangled with the drive shaft. Wrap it around a stationary part underneath the car.

Make an appointment at the muffler shop.

Spray a liberal amount of penetrating oil on the broken bolt. Lightly tap the bolt from each side to allow the oil to seep in. Spray the bolt again and let sit for 24 hours if possible. Spray the bolt once or twice during the wait.

Clench the bolt in a pair of locking pliers if there is enough sticking out above the surface to grip. Try applying pressure to see if the penetrating oil loosened it enough to remove normally. Be careful not to break the bolt further.

Put on the safety goggles. Using the grinder, grind the bolt until it is flush with the surface, then use the punch and hammer to mark the drill guide in the exact center of the bolt.

Insert a small left-handed drill bit (less than 1/8 inch) into the drill as far down as it will go. This increases the control you have over the bit. Place the drill into the punch hole and begin drilling slowly while adding pressure. Reverse the drill and clean out the shavings every so often.

Increase the size of the bits gradually to increase the hole diameter after each successful pass. Repeat this process until only the threads of the bolt remain. Pull out the remaining pieces or pass a tap through the hole to collapse them inward.