Chapter 17 Wheel Alignment Procedures 369 Copyright by Goodheart-Willcox Co., Inc. more than 1″ (2.54 mm) between sides, a suspension part is bent. Make all necessary repairs before continuing with the alignment. Set up the Vehicle for Wheel Alignment Aft er all the above checks have been made and any needed repairs completed, set up the vehicle for the alignment. Do not lower the vehicle onto the rack yet. Th e wheels must be free to turn for alignment head installation. Curb Weight For the most accurate alignment, the vehicle must be at its correct curb weight. Curb weight is the weight of the vehicle with all its normal accessories, a full tank of gas, and a spare tire, but without the driver or passengers. Some vehicles normally carry heavier-than-normal loads. Examples are trucks used for deliveries and cars used to carry a salesper- son’s samples. If the vehicle is used for any of these purposes, ask the driver to bring in the vehicle when it is carrying its normal load. Note that the ride height must be within speci- fi cations regardless of the load. Never try to align a vehicle to compensate for overload- ing. Doing so may place additional stresses on already over- loaded steering and suspension parts. Attempting to align a vehicle to compensate for overloading may also result in dangerous handling problems. In addition, when the vehi- cle is aligned to compensate for overloading, it will be mis- aligned as soon as the excess load is removed. Some imported vehicle specifi cations call for adding weight to the vehicle to simulate the average weight of pas- sengers and luggage. Th is extra weight may be placed in the trunk or in the backseat. Refer to the manufacturer’s speci- fi cations for exact weight and placement. If the weight is to be placed in the backseat, make sure the upholstery will not be damaged. Obtain Alignment Specifications Alignment specifi cations vary from vehicle to vehicle, depending on the year, model, engine size, and whether or not power steering is used. Never guess at the specifi cations, even if you just fi nished aligning a vehicle “just like it.” All vehicle manufacturers publish alignment specifi cations. In addition, many alignment equipment manufacturers, sus- pension and steering parts suppliers, and other aft ermarket companies publish lists of specifi cations for all makes of vehicles. General shop manuals, such as Motor, Mitchel, and Chiltons, usually contain lists of alignment specifi cations. Most lists cover common vehicles for about 15–20 years. Specifi cations for vehicles more than 20 years old can gen- erally be found in older service manuals. Some electronic alignment machines have fi les containing the needed speci- fi cations. Be sure you have the correct alignment specifi ca- tions before beginning the alignment. Install Alignment Equipment Modern alignment equipment is precise and must be installed carefully to ensure accurate alignment. Most mod- ern alignment heads are clamped to the wheel rim. Th e fol- lowing procedures apply to most alignment heads. Always consult the manufacturer’s service manual when there are questions as to how to install the equipment you are using. Removing Wheel Covers/Wheels If wheel covers are used, they must generally be removed. Many wheel covers are held to the rim by wheel cover locks. Th ese locks can be removed using a special key. A typical wheel lock key is shown in Figure 17-15. Some wheel lock keys are stored in the glove compartment or console oth- ers are installed in a special compartment in the trunk. Aft er locating the key, remove the decorative cover over the lock and use the key to unscrew the lock. Some wheels are secured with a special wheel locknut, Figure 17-16. A special key is needed to remove this type of locknut. Th ese locknuts should never be installed or removed with an impact wrench. Note: After using the wheel lock key, replace it in the vehicle. If the key is not replaced, the driver will not be able to remove the tire in an emergency. Crushed frame Toyota Figure 17-13. A vehicle frame that has been damaged from a collision. General Motors Figure 17-14. Checking for setback by measuring from the rear of each tire to the fender opening.