Chapter 17 Wheel Alignment Procedures 377 Copyright by Goodheart-Willcox Co., Inc. Warning: Never bend suspension or steering parts to make alignment adjustments unless specifically recommended by the manufacturer. Various heat treating (tempering) methods are used to harden steering and suspension components. The heat-treated metal is stronger than the original metal, but it is brittle and cannot be reshaped. Attempting to straighten a heat-treated part by bending may cause hairline fractures, metal fatigue, or other damage that may not be visible. Similarly, never weld any suspension or steering part. Welding destroys the heat treatment, making the part too soft to withstand the stresses of operation. If a welded part is reinstalled on the vehicle, it may fail in use and cause an accident. Since the adjustment devices are oft en located under the vehicle’s hood, it may be necessary to remove some shrouds or parts of the air cleaner ducting to gain access to these devices. Always remember to replace these parts before starting the engine. Parts or tools carelessly left where they can contact the moving parts may be damaged, or they may damage the engine. Most alignment technicians try to set the caster and camber to compensate for road crown, discussed in Chapter 16. Since the slope of the road is always to the right, the caster and camber split can be set to cause the vehicle to drift slightly to the left . Th erefore, camber should be slightly more positive on the left side than the right, Figure 17-32. Caster should be slightly more negative on the left than the right. With either angle, the split between sides should be no more than 1/2°. Th is is usually called caster split or camber split, although the terms camber spread, cross camber, caster spread, and cross caster are also used when referring to the split. Camber and Caster—MacPherson Strut Suspensions Caster and camber are sometimes adjusted by moving the top of the strut tower or turning the entire strut assembly. Some adjusters alter only camber or only caster. On some vehicles with MacPherson strut suspensions, the camber or caster are not adjustable. On many cars and trucks with MacPherson struts, camber is adjusted by turning an eccentric cam on the top or bottom strut bolt that secures the strut to the steering knuckle, Figure 17-33. To make the adjustment, loosen both bolts and turn the eccentric until camber is correct. Th en tighten the bolt without the eccentric while holding the eccentric in position. On other vehicles, the eccentric is attached to the lower control arm bushing, Figure 17-34. Th e adjusting bolt must be loosened and the cam turned to make the adjustment. Some vehicles have a camber adjustment consisting of slotted holes in the vehicle’s body at the top of the strut mounting. To make the camber adjustment, loosen the nuts holding the top of the strut tower and slide the tower in or out, Figure 17-35. Th en tighten the nuts, making sure the tower does not move as the nuts are tightened. In a similar design, one bolt pivots in the top of the strut tower, while the other moves in a slotted hole, Figure 17-36. Loosen the attaching nuts, pry the tower to the proper position, and then tighten the nuts. Many vehicles have slotted holes where the strut is attached to the steering knuckle, Figure 17-37. To adjust camber on these vehicles, loosen the nuts and bolts and push or pull the wheel until camber is correct. Th en tighten the strut bolts. For best results, have an assistant hold the wheel +1.5° 0° Zero camber Positive camber Hunter Figure 17-32. Front suspension, as viewed from the front of the vehicle, showing positive camber on the left (driver’s) side and 0° (zero) on the right (passenger) side. Eccentric cam and bolt MacPherson strut Specialty Equipment Corp. Figure 17-33. Adjusting camber on a front MacPherson strut. Turning the eccentric cam and bolt moves the strut.