| Jack: | A device for lifting the vehicle, or part of the vehicle, off the ground to facilitate repairs. |
| Jack Knife: | The action of a vehicle (tractor) with a trailer in which the trailer and the vehicle form a "V" instead of normally being pulled in a straight line. Usually this is the result of a skid in which the trailer swings around dangerously and tries to overtake the cab. |
| Jack Stand: | A safety device that keeps the vehicle from falling to the ground if the lifting jack is removed or faulty. Most jobs require two jack stands for safety |
| Jack Up: | to raise using a jack |
| Jalopy: | a worn-out old car |
| Jam: | A traffic jam |
| Jam on the Brakes: | The action of quickly depressing the brake pedal (pulling the brake lever on a motorcycle or bicycle) especially in an emergency situation. |
| Jet: |
[1] A small precision-made hole. Often a brass fitting placed
inside one of the passages of a carburetor to control the flow of
gasoline, air, or air/fuel mixture. [2] The nozzle containing such a hole. |
| Jig: | device used in the accurate machining of good in process by holding the goods firmly and guiding tools exactly to position. |
| Joint: | [1] Where two pieces meet when a
structure is made of smaller pieces. [2] A flexible or firm connector between two rods. |
| jounce: | The action of bouncing. |
| Joyride: |
[1] A reckless drive in a stolen car. [2] To go for a joyride |
| Joyrider: | one who goes for a joyride |
| Juggernaut: | (Br) a very large transport truck |
| jumper cables: |
Cables used to start a disabled vehicle by conducting electrical current
from the battery of one vehicle to another so that the disabled vehicle
can be started and begin to generate it own power.
(Br) - jump leads |
| Jump Start: | The act of using jumper cables on a weak battery to start a disabled vehicle. |
| Junk: |
[1] Scrap; unwanted material, e.g, unwanted car parts. [2] to scrap, to throw away unwanted material. |
| junkyard: | A place where cars are sent for scrap. Also called "auto graveyard" or "auto wrecker's lot." |
| Jury Rig: | The action of cobbling something together instead of put together according to specifications. |