CDX Chapter 20 Exam

MAINTENANCE AND REPAIR - ANSWER-Tires are one of the most maintenance-intensive parts of a vehicle. They require regular visual inspections, pressure inspections, and rotations. Visual inspections of the tires and wheels should be made whenever a vehicle comes into a shop for any work FIGURE 1. It is common to check for any unusual wear patterns and for any embedded objects or other signs of damage. If the vehicle is not equipped with a TPMS, then the operator should be encouraged to check the pressure at least monthly. Another task is rotating the tires. Most manufacturers recommend that the tires be rotated at each oil change to even out the wear and extend the life of the tires. Research the vehicle and service information for more information. Tools For Servicing Tires - ANSWER-To service tires in an efficient manner, you must have the appropriate tools and equipment. The basic equipment list should consist of: Tire pressure gauge: Used to check the air pressure in tires. Tread depth gauge: Used to measure the tire's tread depth. Valve stem tool: Used to remove and install tubeless valve stems in rims. Valve core tool: Used to remove and install valve cores in valve stems. Tire-changing machine capable of handling the range of tires that the shop stocks: If the shop handles run-flat tires, then the tire-changing machine must be designed to handle the more robust bead and sidewalls. Tire dunk tank: Used to locate leaks in tires and rims. Tire spreader: Used to spread the sidewalls of a tire for easier access during tire patching. Air tire buffer: Used to lightly buff the inside surface of the tire as preparation for tire patching. Patch stitching tool: Used to apply pressure to the patch when positioning it. Tire inflation cage: Used to contain the tire and rim during tire inflation in the event of a tire explosion. Wheel balancing machine capable of handling the range of tires that the shop stocks. Variety of wheel weight styles to cover the various styles of wheels. Wheel weight hammer: Used to remove and install wheel weights onto rims. TPMS reset tool: Used to reset the TPMS (not required on all TPMS-equipped vehicles). Common Issues in Tires and Wheels - ANSWER-Common tire and wheel issues include: Air loss: The most common issue with tires is air loss. Tires normally lose a small amount of air over time and require periodic refilling. Punctures occur that cause leaks of various sizes. Valve stems and tire beads can also allow air to leak from the tire. An out-of-balance tire or wheel: The wheel and tires must be balanced, with the weight equally distributed throughout. When a tire rotates, any points of unequal weight will