Chapter 17 Wheel Alignment Procedures 385 Copyright by Goodheart-Willcox Co., Inc. the scan tool. Road test the vehicle to ensure that steering eff ort is equal in both directions. Make sure that the steering system warning light is off . If necessary, reconnect the scan tool and check that no codes have been reset. Making the Final Alignment Check Aft er making all adjustments, recheck front and rear align- ment. Rear camber and toe should be correct and equal on both sides. Front camber and caster should be within specifi cations, with an allowance for road crown. Th e steer- ing wheel should be in the straight-ahead position with the front wheels pointed straight ahead. All fasteners should be torqued to specifi cations. Removing the Vehicle from the Alignment Rack If your alignment machine is equipped with a printer, make a printout of the alignment settings aft er all checks, adjust- ments, and rechecks are made. Th e printout should show the alignment before and aft er adjustment. Remove the align- ment heads from wheels and reinstall the wheel covers if necessary. Remove the brake pedal lock and the steering wheel lock. If the vehicle is equipped with an electronic sus- pension, turn the trunk switch to the on position. Lower the rack to the fl oor then carefully drive the vehicle off the rack. Road Testing the Vehicle Make a fi nal road test when the wheel alignment is fi nished. Th is road test does not have to be extensive, but it should be long enough to ensure that the alignment is correct and the vehicle does not have any other suspension and steering problems. Aft er alignment, the vehicle should not pull during acceleration or braking. It should track well, without exces- sive wander. Th e suspension should not make any noise. Th e steering wheel should be centered when driving straight ahead. If the vehicle exhibits any problem, return it to the alignment rack and recheck alignment. Frame Straightening If the alignment cannot be corrected by moving the adjust- ing devices, replacing parts, or using aft ermarket alignment devices, the frame or cradle may require straightening to obtain proper alignment. Collision repair shops, or body shops, generally perform frame straightening. For this oper- ation, the body shop must be equipped with a special frame repair fi xture pneumatic, hydraulic, or mechanical pulling devices and measuring tools. Figure 17-54 shows a vehicle installed on a frame repair fi xture. Th e fi rst step is to measure the frame at selected points and compare the measurements with the specifi cations, Figure 17-55. Aft er the frame is measured and the amount of needed movement determined, the pulling devices are attached to the frame where needed, Figure 17-56. Th e pulling devices are used to bend the frame into position. In most cases, the frame must be pulled slightly beyond its intended position. When the pulling force is removed, the frame will spring back to the proper position. Vehicle body Wheels Repair stand Frame repair fixture to vehicle attachment Mercedes-Benz Figure 17-54. A vehicle placed on a frame-and-body repair fixture.