Every year, thousands of ordinary citizens are hurt--some seriously--because they failed to follow established safety procedures when repairing cars or light trucks. Their injuries all come under the "preventable" heading. Safety precautions include the following:
1. Always place a sturdy jack stand under the frame of a car that you have raised using a bumper jack or a scissors jack. The jacks cannot be trusted, and the vehicle may fall unexpectedly, and with no warning.
2. Once you have a jack stand in place, block the opposite (and diagonal) wheel to prevent the car from rolling. That is, if you are changing the right-front tire, place blocks (sometimes called chocks) on both sides of the left-rear tire. The blocks that I prefer are pieces of 4x4 posts, about one foot long each.
3. Use only quality tools, even on the simplest of repairs. Cheap tools will fail, crack or slip on the nut or bolt you are attempting to turn. Auto-repair shops and larger hardware stores carry tools that have a lifetime guarantee. Cheap tools lack such a guarantee. Additionally, if you are using sockets that attach to ratcheting wrenches, use 6-point sockets rather than 12-point sockets for a better grip on the nuts and bolts.
4. Don't wear jewelry of any kind when working on a motor vehicle. Set aside rings, watches, necklaces, etc., before attempting any repairs. Gold rings are especially dangerous because they conduct electricity. If your ring finger ever gets between the positive post on the battery and any other metal part on the vehicle, 400 amperes of current will flow through the ring, causing serious damage to your fingers and hand. Metal watch bands can also cause harmful short circuits.
5. Choose your work clothes carefully. Never lean over a running engine if you are wearing a necktie, for it takes just an instant for a moving belt or pulley to catch on the tie and yank you into the engine area. Also, do not wear shirts with shirttails hanging out for the same reason. Always button your cuffs if you are wearing a long-sleeve shirt.
6. If doing electrical work of any kind, always disconnect the negative battery cable from its post to prevent accidental short circuits. Additionally, if you must remove the battery for any reason, always disconnect the negative cable before you disconnect the positive cable. Reason: If you use a metal wrench on a positive cable connection (negative cable still attached), and the wrench inadvertently comes in contact with any other metal part in the engine area, you will have an immediate short circuit. You do not run that risk if you disconnect the negative cable first.
7. Wear clear protective glasses if you are using power or impact tools on a motor vehicle. That is the only way to protect your eyes from chips of metal or other foreign objects that a power drill or an impact wrench may cause.
8. Finally, think what you are doing at all times. Know what the next step must be. Remember, a motor vehicle is nothing but a big, dumb machine that is never to be trusted. If something can go wrong, it probably will go wrong. Stay safe.
The author is an ASE-certified automotive repair technician.
