CHAPTER 34 Alignment Diagnosis and Service
Contents
1. Upper Saddle River NJ 07458 All rights reserved MEMORY STEER o test for memory steer follow these simple steps during a test drive With the vehicle stopped at an intersection or in a parking area turn the steering wheel completely to the left stop and then straighten the wheel without going past the straight ahead position Lightly accelerate the vehicle and note any tendency of the vehicle to lead or pull toward the left Repeat the procedure turning the steering wheel to Autom Miei i the right is Systems 5 e Copyr ed 2008 2004 e 1995 Pea Upper Sad Educ dle River NJ 7458 yh RET 2 Inc rved MEMORY STEER A binding suspension or steering component is the most likely cause of memory steer Disconnect each wheel from its tie rod end and check for free rotation of movement of each wheel Each front wheel should rotate easily without binding or roughness Repair or replace components as necessary to eliminate the binding condition Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved The Five Wheel Alignment Gu REAL WORLD FIX The steering wheel should always be straight when driving on a straight level road If the steering wheel is not straight the customer will often think that the wheel alignment is not correct One such customer2. KINGPIN TWIN I BEAM SUSPENSION INCLUDED ANGLE DIAGNOSIS SAI KPI CAMBER CORRECT GREATER THAN SPECS LESS THAN SPECS GREATER THAN SPECS LESS THAN SPECS GREATER THAN SPECS GREATER THAN SPECS LESS THAN SPECS Automotive Chassis Systems 5 e By James D Halderman GREATER THAN SPECS CORRECT GREATER THAN SPECS CORRECT BENT SPINDLE BENT BEAM BENT BEAM AND SPINDLE BENT BEAM Copyright 2010 2008 2004 2000 1995 Pearson Education Inc Upper Saddle River NJ 07458 All rights reserved CHECKING FRAME ALIGNMENT OF FRONT WHEEL DRIVE VEHICLES Many front wheel drive vehicles mount the drive train engine and transaxle and lower suspension arms to a subframe or cradle If the frame is shifted either left or right this can cause differences in SAI included angle setback and camber Automotiv Pu is Systems 5 e Copyright O 2010 2008 2004 E 1995 P Upper Sad Educ qu Inc r NJ A LAIT rights reserved CHECKING FRAME ALIGNMENT OF FRONT WHEEL DRIVE VEHICLES LEFT SAI 16 INCLUDED RIGHT SAI 8 LEFT SAI 12 INCLUDED RIGHT SAI 12 LEFT CAMBER 3 ANGLE 13 RIGHT CAMBER 5 LEFT CAMBER 1 ANGLE 1 RIGHT CAMBER 1 10 10 544 10 0 40 10 10 a9 gt 10 10 20 o 20 Voll blu Vlll Voldindindun I VEHICLE CENTERLINE VEHICLE CENTERLINE i SUBFRAME CENTERLINE SUBFRAME CENTERLINE FIGURE 34 15 In this example both SAI and
3. All rights reserved CHAPTER QUIZ 7 The vehicle above will a Pull toward the right and feather edge both tires ve Pull toward the left c Wear the outside of the left tire and the inside of the right tire a None of the above Use the following information to answer question 7 Specifications Min Preferred Max Camber degree 0 1 0 1 4 Caster degree 8 1 5 zd Toe inch 10 06 5 Results L R Camber degree M 6 Caster degree 1 8 16 Toe inch Vale d 2 Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved CHAPTER QUIZ 8 The vehicle above will a Pull toward the left ve Pull toward the right c Wander a Lead to the left slightly Use the following information to answer questions 8 and 9 Specifications Min Preferred Max Camber degree 1 4 T 1 2 1 Caster degree 0 2 4 Toe inch 1 16 1 16 3 16 Results L R Camber degree 0 3 0 1 Caster degree 3 6 1 8 Toe inch 1 16 1 32 Copyright 2010 2008 2004 2000 1995 Pearson Education Inc Automotive Chassis Systems 5 e Upper Saddle River NJ 07458 All rights reserved By James D Halderman CHAPTER QUIZ 9 The vehicle above will a Wander ve Wear tires but will not pull c Will pull but not wear tires a Pull toward the left and cause feather edge tire wear Use the following information to
4. All rights reserved FRONT CAMBER CASTER ADJUSTMENT METHODS METHODS OF ADJUSTMENT TOOLS AND ADJUSTMENT DEVICES MAY BE AVAILABLE FROM AFTERMARKET SUPPLIERS TO PERFORM ADJUSTMENTS IN CASES WHERE MANUFACTURERS DO NOT MAKE SUCH PROVISIONS CASTER amp CAMBER CASTER amp CAMBER CASTER amp CAMBER ADJUSTMENT ADJUSTMENT ADJUSTMENT SLOTTED SHIMS MOLES a ose ot TO INCREASE CASTER MOVE SHIMS TO INCREASE CASTER MOVE SHIMS LOOSEN BOLTS MOVE UPPER ARM REAR TO FRONT CAMBER CHANGE FRONT TO REAR CAMBER CHANGE SHAFT TO OBTAIN SPECIFIED SHIM THICKNESS EQUALLY SHIM THICKNESS EQUALLY READINGS USE SPECIAL TOOL CASTER amp CAMBER CASTER amp CAMBER CAMBER ADJUSTMENT ADJUSTMENT ADJUSTMENT FIGURE 34 29 An example of the many methods that are commonly used to adjust front caster and camber TO INCREASE CASTER MOVE SHIMS TO ADJUST ROTATE CAM BOLTS TO ADJUST CAMBER LOOSEN FRONT TO REAR CAMBER CHANGE SET CAMBER FIRST CHECK ADJUST TWO NUTS ON UPPER ARM AND SHIM THICKNESS EQUALLY CASTER RECHECK CAMBER MOVE WHEEL IN OR OUT FRONT CASTER OR CAMBER ADJUSTMENT CAMBER ADJUSTMENT REAR TOE ADJUSTMENT ECCENTRIC CAM THREADED ee ROD TO INCREASE CASTER TO POSITIVE TO INCREASE OR DECREASE LOOSEN NUT ON UPPER CONTROL LENGTHEN STRUT INCREASE OR CAMBER SETTING ROTATE ARM AND ROTATE BOLT TO SET DECREASE TOE IN BY LENGTHENING CAM BOLT CAMBER OR SHORTENING ROD Automotive Chassis Systems 5 e Copyright 2010 2008 2004
5. 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved ADJUSTING FRONT CAMBER CASTER Most SLA type suspensions can be adjusted for caster and camber Most manufacturers recommend adjusting caster then camber before adjusting the toe As the caster is changed such as when the strut rod is adjusted the camber and toe also change Automotiv Pu is Systems 5 e Copyright O 2010 2008 2004 E 1995 P Upper Sad Educ gen Te r NJ A LAIT rights reserved ADJUSTING FRONT CAMBER CASTER FIGURE 34 30 If there is a nut on both sides of the strut rod bushing then the length of the rod can be adjusted to change caster LENGTHEN OR SHORTEN STRUT ROD TO CORRECT CASTER Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc Upper Saddle River NJ 07458 All rights reserved By James D Halderman ADJUSTING FRONT CAMBER CASTER Automotive Chassis Systems 5 e By James D Halderman FRAME NUT UPPER CONTROL ARM 4 SUBTRACT SHIMS TO INCREASE SUBTRACT SHIMS EQUALLY TO INCREASE POSITIVE CASTER C POSITIVE CAMBER OR ADD SHIMS EQUALLY TO REDUCE POSITIVE CAMBER ADD SHIMS TO INCREASE POSITIVE CASTER FIGURE 34 31 Placing shims between the frame and the upper control arm pivot shaft is a popular method of alignment for many SLA suspensions Both camber and caster can be easily changed by adding or
6. FIGURE 34 16 This is the same vehicle as shown camber are far from being equal side to side in Figure 18 15 except now the frame cradle has However both sides have the same included been shifted over and correctly positioned Notice angle indicating that the frame may be out of how both the SAI and camber become equal alignment An attempt to align this vehicle by without any other adjustments necessary adjusting the camber on both sides with either factory or aftermarket kits would result in a totally incorrect alignment Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved Damage Analysis Tips TECH TIP o check if a vehicle has been in a collision technicians should look for the following Drive the vehicle through a water puddle to see if the tire marks are wider than the tires If they are then the front and rear wheels are not tracking correctly f the setback is out of specifications then the front of the vehicle may be damaged If the thrust angle is out of specifications then rear suspension damage is likely Automotiv EE is Systems 5 e Copyright O 2010 2008 ao 2000 1995 P Educ ation Inc Upper Sad r NJ 07458 yh rights reserved TYPES OF ALIGNMENTS There are three types of alignment geometric centerline thrust line and four wheel alignment GEOMETRIC CENT
7. alignment technician became upset when a beginning technician opened the driver s door to lock the steering wheel in a straight ahead position on the vehicle being aligned The weight of the open door caused the vehicle to sag This disturbed the level position of the vehicle and changed all the alignment angles Automotiv EE is Systems 5 e Copyright O 2010 2008 ao 2000 1995 P Educ ation Inc Upper Sad r NJ 07458 yh rights reserved Keep the Doors Closed but the Window Down TECH TIP The beginning technician learned an important lesson that day Keep the window down on the driver s door so that the steering wheel and brakes can be locked without disturbing Automotiv ae the vehicle weight balance by opening a door The brake pedal must be locked with a pedal depressor to prevent the wheels from rolling as the wheels are turned during a caster sweep The steering must be locked in the straightahead position when adjusting toe is Systems 5 e Copyright 2010 2008 uc E 1995 P Upper Sad Educ qu r NJ A LAIT rights r Inc rved ALIGNMENT SPECIFICATIONS READING ALIGNMENT SPECIFICATIONS MAXIMUM MINIMUM PREFERRED METHOD PLUS OR MINUS METHOD DEGREES MINUTES AND FRACTIONS FINDING THE MIDPOINT OF SPECIFICATIONS e Chassis Systems 5 e Copyright O 2010 2008 2004 a 995 Pearson Education Inc E Hald erman 2 Upper Saddle Riv 1G 07458 All rights reserved ALIGNMENT SETUP PROCED
8. answer questions 8 and 9 Specifications Min Preferred Max Camber degree 1 4 T 1 2 1 Caster degree 0 2 4 Toe inch 1 16 1 16 3 16 Results L R Camber degree 0 3 0 1 Caster degree 3 6 1 8 Toe inch 1 16 1 32 Copyright 2010 2008 2004 2000 1995 Pearson Education Inc Automotive Chassis Systems 5 e Upper Saddle River NJ 07458 All rights reserved By James D Halderman CHAPTER QUIZ 10 Which alignment angle is most likely to need correction and cause the most tire wear a loe b Camber c Caster a SAI KPI Automotive Chassis Systems 5 e Copyright 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved
9. diagnostic chart to check for hidden damage that a visual inspection may miss Automotiv Pu is Systems 5 e Copyright O 2010 2008 2004 E 1995 P Upper Sad Educ gen Te r NJ A LAIT rights reserved CHECKING FOR BENT STRUTS SPINDLES OR CONTROL ARMS DIAGNOSING SAI CAMBER AND INCLUDED ANGLE SLA AND STRUT SLA SUSPENSIONS CAMBER CORRECT LESS THAN SPECS LESS THAN SPECS GREATER THAN SPECS LESS THAN SPECS GREATER THAN SPECS GREATER THAN SPECS LESS THAN SPECS INCLUDED ANGLE LESS THAN SPECS CORRECT DIAGNOSIS BENT STEERING KNUCKLE OR SPINDLE BENT LOWER CONTROL ARM BENT LOWER CONTROL ARM AND STEERING KNUCKLE OR SPINDLE BENT UPPER CONTROL ARM Eom m m s RM FIGURE 34 14 By checking LESS THAN SPECS CORRECT GREATER THAN SPECS LESS THAN SPECS GREATER THAN SPECS LESS THAN SPECS GREATER THAN SPECS LESS THAN SPECS LESS THAN SPECS GREATER THAN SPECS LESS THAN SPECS GREATER THAN SPECS GREATER THAN SPECS LESS THAN SPECS GREATER THAN SPECS CORRECT GREATER THAN SPECS BENT SPINDLE AND OR STRUT BENT SPINDLE AND OR STRUT BENT CONTROL ARM OR STRUT TOWER OUT AT TOP BENT CONTROL ARM OR STRUT TOWER OUT AT TOP ALSO BENT SPINDLE AND OR STRUT BENT CONTROL ARM OR STRUT TOWER OUT AT TOP ALSO BENT SPINDLE AND OR STRUT STRUT TOWER IN AT TOP STRUT TOWER IN AT TOP AND BENT SPINDLE AND OR BENT STRUT the SAI camber and included angle a damaged suspension component can be determined by using this chart
10. is rotated the upper control arm moves in and out By adjusting both eccentric cams both camber and caster can be adjusted Copyright 2010 2008 2004 2000 1995 Pearson Education Inc Upper Saddle River NJ 07458 All rights reserved By James D Halderman ADJUSTING FRONT CAMBER CASTER a BE a EET FIGURE 34 35 Typical shim alignment chart As noted 1 8 in 0 125 shims EIE cS te can be substituted for the 0 120 in shims 1 32 in 0 0625 shims can be substituted for the 0 060 in shims and mem 1 32 in 0 03125 shims can be m substituted for the 0 030 in shims FRONT 100 200 201 REAR 201 100 010 FRONT REAR 00 D 1 DETERMINE VEHICLE S CURRENT CASTER AND CAMBER MEASUREMENTS 2 USING THE CURRENT CASTER READING READ DOWN THE APPROPRIATE COLUMN TO THE LINES CORRESPONDING TO THE CURRENT CAMBER READING 3 CORRECTION VALUES WILL BE GIVEN FOR THE FRONT AND REAR BOLTS EXAMPLE CURRENT READING 1 6 CASTER 0 4 CAMBER BY READING DOWN THE CHART FROM 1 6 CASTER TO 0 4 CAMBER YOU WILL FIND THAT THE FRONT BOLT REQUIRES AN ADJUSTMENT OF 101 AND THE REAR BOLT REQUIRES AN ADJUSTMENT OF 010 DEGREES CAMBER Automotive Chassis Systems 5 e Copyright 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved SETTING TOE Front toe is the last angle that should be adjusted and is the most likely to need correction This has led
11. it stored stuck to a metal plate or metal tool box Automotive Chassis Systems 5 e Copyright 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved PREALIGNMENT CHECKS Before checking or adjusting the front end alignment the following items should be checked and corrected if necessary as part of the prealignment checks Check all the tires for proper inflation pressures Check the wheel bearings for proper adjustment Check for loose ball joints or torn ball joint boots Check the tie rod ends for damage or looseness Check the center link or rack bushings for play Check the pitman arm for any movement Check for runout of the wheels and the tires Automotiv Pu is Systems 5 e Copyr ed 2008 2004 e 1995 Pea Educ pu Inc Upper Sad dle River NJ 7458 yh RET rved PREALIGNMENT CHECKS Check for vehicle ride height should be level front to back as well as side to side Check for steering gear looseness at the frame Check for improperly operating shock absorbers Check for worn control arm bushings Check for loose or missing stabilizer bar attachments Check the trunk for excess loads Check for dragging brakes Automotiv Pu is Systems 5 e Copyr Ead 2008 2004 i 1995 Pea Educ pu Inc Upper Sad dle River NJ 7458 yh RET rved PREALIGNMENT CHECKS A BAD TOE ADJUSTMENT CAN ALSO CA
12. removing shims Copyright 2010 2008 2004 2000 1995 Pearson Education Inc Upper Saddle River NJ 07458 All rights reserved ADJUSTING FRONT CAMBER CASTER UPPER SHIMS CONTROL ARM FIGURE 34 32 The general rule of thumb is that a 1 8 in shim added or removed from both shim locations changes the camber angle about 1 2 degree Adding or removing a 1 8 in shim from one shim location changes the caster by about 1 4 degree Automotive Chassis Systems 5 e Copyright 2010 2008 2004 2000 1995 Pearson Education Inc Upper Saddle River NJ 07458 All rights reserved By James D Halderman ADJUSTING FRONT CAMBER CASTER FRAME PIVOT SHAFT NUT UPPER CONTROL ARM ADJUSTMENT TOOL 2 Automotive Chassis Systems 5 e FIGURE 34 33 Some SLA type suspensions use slotted holes for alignment angle adjustments When the pivot shaft bolts are loosened the pivot shaft is free to move unless held by special clamps as shown By turning the threaded portion of the clamps the camber and caster can be set and checked before tightening the pivot shaft bolts Copyright 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved ADJUSTING FRONT CAMBER CASTER Automotive Chassis Systems 5 e ECCENTRIC CAMS UPPER CONTROL ARM FIGURE 34 34 When the nut is loosened and the bolt on the eccentric cam
13. the turning radius by turning one wheel to an angle specified by the manufacturer and observing the angle of the other front wheel Most newer alignment machines can display turning angle based on sensor readings and therefore the protractor scale on the turn plate is not needed or used Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved SPECIFICATIONS VERSUS ALIGNMENT READINGS Secure both the alignment specifications from the manufacturer and the alignment readings and compare the two Before starting an alignment the smart technician checks the SAI included angle setback and toe out on turns to make sure that there is no hidden damage such as a bent spindle or strut that was not found during the prealignment inspection Setback is also a diagnostic angle and should be less than 0 5 in 13 cm or 1 2 degree If setback is greater than 0 5 in 13 cm or 1 2 degree check the body frame and cradle for accident damage or improper alignment Automotiv Pu is Systems 5 e Copyr Ss 2008 2004 e 1995 Pearson Educ pu Inc Upper Sadd le River NJ 7458 yh RET rved CHECKING FOR BENT STRUTS SPINDLES OR CONTROL ARMS Even a minor bump against a curb can bend a spindle or a strut housing Before attempting to correct an alignment check all the angles and use the appropriate
14. upper strut mount s worn power steering pump worn P S belt Loose wheel bearings worn steering or Suspension components loose steering gear mount excessive steering gear play loose or worn steering coupler Excessive positive caster excessive negative camber improper tire inflation too wide wheel tire combination for the vehicle worn or loose shocks worn springs Incorrect camber or caster bent spindle or strut binding suspension or steering components improper tire inflation Incorrect alignment defective or improperly inflated tires worn steering or Suspension parts bent spindle or strut worn or loose steering gear loose wheel bearings Defective or improperly inflated tires incorrect turning angle TOOT bent steering arms excessive wheel setback poor driving habits too fast for conditions worn suspension or steering parts Loose or broken stabilizer bar links or bushings worn shocks or mountings broken or sagging springs uneven vehicle load uneven or improper tire pressure Binding steering linkage binding steering gear binding upper strut mount ball joint or kingpin Misalignment of steering linkage bent steering arm or frame defective or sagged springs uneven load bent spindle or strut Bent spindle or strut bent steering arm misaligned frame worn torque strut defective engine or transaxle mounts drive axle misalignment mismatched or unequally inflated tires Automotive Chassis Systems
15. while the toe is set Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved STEERING WHEEL REMOVAL If the steering wheel must be removed first disconnect the airbag wire connector at the base of the steering column This reduces the chance of personal injury and prevents accidental airbag deployment Hemove the center section of the steering column by removing the retaining screws including the inflator module on vehicles equipped with an airbag After removal of the airbag inflator module remove the steering wheel retaining nut Note the locating marks on the steering wheel and steering shaft Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 e 1995 P Educ qu Inc By James D Ha Upper Saddle River NJ edi LAIT rights reserved STEERING WHEEL REMOVAL ALIGNMENT MARK ON STEERING SHAFT ALIGNMENT MARK ON STEERING WHEEL FIGURE 34 40 Most vehicles have alignment marks made at the factory on the steering shaft and steering wheel to help the service technician keep the steering wheel in the center position Copyright 2010 2008 2004 2000 1995 Pearson Education Inc Automotive Chassis Systems 5 e By James D Halderman Upper Saddle River NJ 07458 All rights reserved STEERING WHEEL REMOVAL FIGURE 34 41 A puller being used to remove a steering wheel a
16. 5 e Copyright 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved SUMMARY i Before attempting to align any vehicle it must be checked for proper ride height trim height tire conditions and tire pressures A thorough inspection of all steering and Suspension components must also be made 2 Memory steer is a condition that causes the vehicle to lead or pull to the same direction it was last steered Binding steering or Suspension components are the most frequent causes of memory steer 3 Torque steer is the pull or lead caused by engine torque being applied to the front wheels unevenly on a frontwheel drive vehicle Out of level drivetrain suspension components or tires are the most common causes of excessive torque steer Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved SUMMARY 4 Lead pull diagnosis involves a thorough road test and careful inspection of all tires 5 There are three types of alignment geometric centerline thrust line and four wheel alignment Only an a four wheel alignment should be used on a vehicle with an adjustable rear suspension e The proper sequence for a complete four wheel alignment is rear camber rear toe front camber and caster and front toe Automotive Chassis Syst
17. ANGLE DRIVE TORQUE FIGURE 34 7 Equal outer CV joint angles produce equal steer torque toe in If one side receives more engine torque that side creates more toe in and the result is a pull toward one side especially during acceleration Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved TORQUE STEER The service technician cannot change the design of a vehicle but the technician can and should check and correct problems that often cause torque steer Check to be sure that the condition is not normal It is normal for front wheel drive vehicles to exert a tug on the steering wheel and steer toward one side usually to the right during acceleration This is especially noticeable when the transmission shifts from first to second gear under heavy acceleration Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved TORQUE STEER To determine how severe the problem is place a strip of masking tape at the top of the steering wheel Drive the vehicle and observe the amount of movement required to steer the vehicle straight during heavy acceleration Hepeat the test with a vehicle of similar make and model If the torque steer is excessive determine and correc
18. DJUSTING REAR CAMBER Adjusting rear camber is the first step in the four wheel alignment process Rear camber is rarely made adjustable but can be corrected by using aftermarket alignment kits or shims If rear camber is not correct vehicle handling and tire life are affected Automotive Chassis Systems 5 e Copyright 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved ADJUSTING REAR CAMBER Before attempting to adjust or correct rear camber carefully check the body and or frame of the vehicle for accident damage including the following Weak springs torsion bars or overloading check ride height Bowed rear axle trailing arm or rear control arm Suspension mount or body dimension not in proper location Incorrectly adjusted camber from a previous repair Automotive Chassis Systems 5 e Copyright 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved NL 1 ECCENTRIC CAM FIGURE 34 20 The rear camber is adjustable on this vehicle by rotating the eccentric cam and watching the alignment machine display Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved ADJUSTING REAR CAMBER CAMBER KNUCKLE ADJUS
19. ERLINE THRUST LINE FOUR WHEEL ALIGNMENT Automotiv Pu is Systems 5 e Copyr Ed 2008 2004 e 1995 Pea Educ pu Inc Upper Sad dle River NJ 07458 yh RET rved TYPES OF ALIGNMENTS Jti FIGURE 34 17 Geometric centerline type alignment sets the lt THRUST LINE front toe readings based on the geometric centerline of the vehicle eane S and does not consider the thrust line of the rear wheel toe angles Courtesy of Hunter Engineering Company Copyright 2010 2008 2004 2000 1995 Pearson Education Inc Automotive Chassis Systems 5 e By James D Halderman Upper Saddle River NJ 07458 All rights reserved TYPES OF ALIGNMENTS ce GEOMETRIC CENTERLINE THRUST LINE FIGURE 34 18 Thrust line alignment sets the front toe parallel with the rear wheel toe Courtesy of Hunter Engineering Company Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc Upper Saddle River NJ 07458 All rights reserved By James D Halderman TYPES OF ALIGNMENTS Ji GEOMETRIC CENTERLINE gt lt THRUST LINE FIGURE 34 19 Four wheel alignment corrects for any rearwheel toe to make the thrust line and the geometric centerline of the vehicle both the same Courtesy of Hunter Engineering Company Automotive Chassis Systems 5 e Copyright 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper S
20. JAMES D HALDERMAN FIFTH EDITION NOTIVE CHASSIS S OVENS Qua CHAPTER 34 Alignment Diagnosis and Service lt a AUTOMOTIVE After studying Chapter 34 the reader will be able to 1 Automotive Chassis Systems 5 e Copyright 2010 2008 2004 E 1995 P Upper Sad By James S D Hald Prepare for ASE Suspension and Steering A4 certification test content area D Wheel Alignment Diagnosis Adjustment and Repair List the many checks that should be performed before aligning a vehicle Describe the proper alignment setup procedure Explain how to correct for memory steer torque steer pull drift lead and wander Describe the use of unit conversion and diagnostic charts Discuss tolerance alignment and how to check for accident damage Educ qu r NJ A LAIT rights r Inc rved Degrees Prealignment checks Eccentric cam Hide height Five wheel alignment Shim chart Four wheel alignment Spoke angle Fractional Thrust line Geometric centerline Tolerance adjustment Memory steer Torque steer Minutes Total toe Copyright 2010 2008 2004 2000 1995 Pearson Education Inc Automotive Chassis Systems 5 e Upper Saddle River NJ 07458 All rights reserved By James D Halderman INTRODUCTION Proper wheel alignment of all four wheels is important for the safe handling of any vehicle When all four wheels are traveling the same path and or being kept nearly ver
21. TER LOWER CONTROL ARM FIGURE 34 21 Some vehicles use a threaded fastener similar to a tie rod to adjust camber on the rear suspension Automotive Chassis Systems 5 e Copyright 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved ADJUSTING REAR CAMBER ADJUSTMENT WEDGE STRUT FIGURE 34 22 Aftermarket alignment parts or kits are available to change the KNUCKLE rear camber CHASSIS LOWER CONTROL ARM Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved The Gritty Solution TECH TIP Many times it is difficult to loosen a Torx bolt especially those used to hold the backing plate onto the rear axle on many GM vehicles A technique that always seems to work is to place some valve grinding compound on the fastener The gritty compound keeps the Torx socket from slipping up and out of the fastener and more force can be exerted to break loose a tight bolt Valve grinding compound can also be used on Phillips head screws as well as other types of bolts nuts and sockets Automotive Chassis Systems 5 e Copyright 2010 2008 2004 ie 1995 P Educ qu Inc By James D Ha id Upper Saddle r NJ 7458 yh rights reserved The Gritty Solution FIGURE 34 23 Full contact plastic or metal shims
22. URES WHEEL ALIGNMENT SPECIFICATIONS CROSS CROSS TOE STEERING CASTER CAMBER TOTAL IN WHEEL CASTER LH RH CAMBER LH RH DEGREES ANGLE 3 s 5 0 s 75 2 0 75 0 3 5 0 75 ae 2 FIGURE 34 9 This alignment chart indicates the preferred setting with a plus or minus tolerance Automotive Chassis Systems 5 e Copyright 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved ALIGNMENT SETUP PROCEDURES After confirming that the tires and all steering and suspension components are serviceable the vehicle is ready for an alignment oetup procedures for the equipment being used must always be followed Typical alignment procedures include the following Drive onto the alignment rack straight and adjust the ramps and or turn plates so that they are centered under the tires of the vehicle Use chocks for the wheels to keep the vehicle from rolling off the alignment rack Automotiv Pu is Systems 5 e Copyr eh 2008 2004 i 1995 Pea Educ pu Inc Upper Sad dle River NJ 7458 yh RET rved ALIGNMENT SETUP PROCEDURES Attach and calibrate the wheel sensors to each wheel as specified by the alignment equipment manufacturer Unlock all rack or turn plates Lower the vehicle and jounce the vehicle by pushing down on the front then rear bumper This motion allows the suspension to become cen
23. USE FEATHERING OF A TIRE WHICH YOU HAVE TO FEEL TO DETECT SINCE THE TIRE MAY LOOK PERFECTLY GOOD AS THIS ONE DOES A TIRE WORN ON THE OUTSIDE EDGES LIKE THIS HAS BEEN RUN UNDERINFLATED N a A amp z tm J a J m a a 3 M i E 3 5 e EI a L 2 AND ATIRE WITH JUST THE CENTER WORN DOWN LIKE THIS HAS BEEN OVERIN FLATED BALD SPOTS OR SCALLOPED EFFECTS ARE USUALLY CAUSED BY UNBALANCED WHEELS TIRE DEFECTS OR WORN SUSPENSION COMPONENTS Terr itil iiss WHEN A TIRE IS WORN ON ONLY ONE SIDE LIKE THIS ONE IT S A PRETTY GOOD INDICATION OF A CAMBER OR TOE PROBLEM Tilliltililluswzgze DNXYIIIIIILILLZZe TTTLLLLLLLILLISJ FIGURE 34 3 Typical tire wear chart as found in a service manual Abnormal tire wear usually indicates a fault in a steering or suspension component that should be corrected or replaced before an alignment is performed Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved PREALIGNMENT CHECKS A B FIGURE 34 4 Measuring points for ride trim height vary by manufacturer Courtesy of Hunter Engineering Company Automotive Chassis Systems 5 e Copyright 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved PREALIGNMENT CHECKS FIGURE 34 5 Measuring to be sur
24. addle River NJ 07458 All rights reserved Ask Yourself These Three Questions TECH TIP An older technician told a beginning technician that the key to success in doing a proper alignment is to ask yourself three questions about the alignment angles Question 1 Is it within specifications Question 2 Is it within 1 2 of the other side of the vehicle Question 3 If the camber and caster cannot be exactly equal side to side in the front is there more camber on the left and more caster on the right to help compensate for road crown Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved How does normal wear affect the alignment angles FREQUENTLY ASKED QUESTION As a vehicle ages the springs sag and steering and suspension components wear When springs sag the ride height changes and the camber usually is reduced and often becomes negative compared to slightly positive when the vehicle was new in most cases When tie rod ends and other steering components wear the front wheels tend to toe out Worn suspension components can cause excessive play making the vehicle unstable and cause the tires to wear abnormally Automotive Chassis Systems 5 e Copyright 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved A
25. can be placed between the axle housing and the brake backing plate to change rear camber toe or both Courtesy of Northstar Manufacturing Company Inc Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved ADJUSTING REAR CAMBER USING PLASTIC OR METAL ALIGNMENT SHIMS ADJUSTING REAR TOE e Chassis Systems 5 e Copyright 2010 2008 2004 EE 5 Pearson Education INC ev anie Halde erman Upper Saddle Riv at 074 58 All rights reserved ADJUSTING REAR CAMBER TIE ROD FIGURE A Dos bul 10E was easi Ser on FIGURE 34 25 By moving various rear suspension this vehicle The adjusting nuts were easy to get members the rear toe can be changed to and turn Adjusting rear toe is not this easy on j every vehicle Automotive Chassis Systems 5 e Copyright 2010 2008 2004 2000 1995 Pearson Education Inc Upper Saddle River NJ 07458 All rights reserved By James D Halderman ADJUSTING REAR CAMBER FIGURE 34 26 The use of these plastic or metal shims requires that the rear wheel as well as the hub assembly and or backing plate be removed Proper torque during reassembly is critical to avoid damage to the shims Automotive Chassis Systems 5 e Copyright 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights rese
26. change is often enough to prevent it from being able to be adjusted to within specifications Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved ALIGNING MODIFIED VEHICLES Alignment alone will not correct these concerns To allow for proper handling the following aftermarket kits and parts are available Camber kits Bump steer kits C a f X Jj d FIGURE 34 45 A typical tire temperature pyrometer The probe used is a needle that penetrates about 1 4 inch 7 mm into the tread of the tire for most accurate readings Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved HIDDEN STRUCTURAL DAMAGE DIAGNOSIS Many accidents result in hidden structural damage that can cause alignment angles to be out of specification If alignment angles are out of specification tolerances then accident damage should be suspected Look for evidence of newly replaced suspension parts body work or repainted areas of the body While a body and or frame of a vehicle can be straightened it must be done by a knowledgeable person using bodymeasuring equipment The first thing that must be done is to determine a datum plane Datum means a basis on which other measurements can be based T
27. complained that the vehicle pulled to the right while driving on a straight road The service manager test drove the vehicle and everything was perfect except that the steering wheel was not perfectly straight even though the toe setting was correct Whenever driving on a straight road the customer would straighten the steering wheel and of course the vehicle went to one side After adjusting toe with the steering wheel straight the customer and the service manager were both satisfied The technician learned that regardless of how accurate the alignment the steering wheel must be straight it is the fifth wheel that the customer notices most Therefore a five wheel alignment rule includes a check of the steering wheel Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved TORQUE STEER Torque steer occurs in front wheel drive vehicles when engine torque causes a front wheel to change its angle from straight ahead Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved TORQUE STEER GREATER STEER TORQUE STEER TORQUE MUST BE ON ONE SIDE CREATES MORE TOE IN EQUAL ON BOTH SIDES VEHICLE STEERS RIGHT a gt q gt gt STEERING TORQUE ds PRODUCED BY OUTER C V JOINT
28. e for sagging frame members or other normal or accident related faults Automotiv Pu is Systems 5 e Copyright O 2010 2008 ue E 1995 P Upper Sad Educ qu Inc r NJ A LAIT rights reserved AFTERMARKET ALIGNMENT METHODS b a FIGURE 34 43 a Aftermarket camber kit designed to provide some camber adjustments for a vehicle that does not provide any adjustment b Installation of this kit requires that the upper control arm shaft be removed Note that the upper control arm was simply rotated out over the wheel pivoting on the upper ball joint Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc Automotive Chassis Systems 5 e Upper Saddle River NJ 07458 All rights reserved By James D Halderman AFTERMARKET ALIGNMENT METHODS FIGURE 34 44 a The installation of some aftermarket alignment kits requires the use of special tools such as this cutter being used to drill out spot welds on the original alignment plate on a strut tower b Original plate being removed c Note the amount of movement the upper strut bearing mount has around the square openings in the strut tower An aftermarket plate can now be installed to allow both camber and caster adjustment Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved ALIGNING ELECTRONIC SUSPENSION VEHICLES When alignin
29. e the left and right sides of the vehicle are of equal height If this measurement is not equal side to side by as little as 1 8 in 3 mm it can affect the handling of the vehicle Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc Automotive Chassis Systems 5 e Upper Saddle River NJ 07458 All rights reserved By James D Halderman LEAD PULL DIAGNOSIS Many alignment requests come from customers attempting to have a lead or pull condition corrected Before aligning the vehicle verify the customer complaint first then perform a careful inspection FIGURE 34 6 The bulge in this tire was not noticed until it was removed from the vehicle as part of a routine brake inspection After replacing this tire the vehicle stopped pulling and vibrating Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved MEMORY STEER Memory steer is a term used to describe the lead or pull of a vehicle caused by faults in the steering or suspension system Often a defective upper strut bearing or steering gear can cause a pulling condition in one direction after making a turn in the same direction Itis as if the vehicle had a memory and pulled in the same direction Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman
30. ems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved REVIEW QUESTIONS 1 Automotive Chassis Systems 5 e By James D Halderman List 10 prealignment checks that should be performed before the wheel alignment is checked and or adjusted Describe the difference between a lead drift and a pull Explain the causes and possible corrections for torque steer Explain the causes and possible corrections for memory steer List the necessary steps to follow for a four wheel alignment Copyright 2010 2008 2004 2000 1995 Pearson Education Inc Upper Saddle River NJ 07458 All rights reserved CHAPTER QUIZ 1 If the tie rod ends become worn which angle is most affected a Camber ve Caster c Toe 4 SAI Automotive Chassis Systems 5 e Copyright 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved CHAPTER QUIZ 2 Technician A says that a vehicle will pull or lead to the side with the most camber or least negative camber Technician B says that a vehicle will pull or lead to the side with the most positive caster Which technician is correct a Technician A only e Technician B only c Both Technicians A and B a Neither Technician A nor B Automotive Chassis Systems 5 e Copyright 2010 2008 2004 2000 1995 Pears
31. fter the steering wheel retaining nut has been removed Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved Locking Pliers to the Rescue TECH TIP Many vehicles use a jam nut on the tie rod end This jam nut must be loosened to adjust the toe Because the end of the tie rod is attached to a tie rod end that is movable loosening the nut is often difficult Every time force is applied to the nut the tie rod end socket moves and prevents the full force of the wrench from being applied to the nut To prevent this movement simply attach locking pliers Vise Grips to hold the tie rod Wedge the pliers against the control arm to prevent any movement of the tie rod By preventing the tie rod from moving full force can be put ona wrench to loosen the jam nut without doing any harm to the tie rod end Automotive Chassis Systems 5 e Copyright 2010 2008 2004 de 1995 P Educ ea Inc By James D Ha Upper Saddle r NJ 07458 all rights reserved Left Thrust Line but a Pull to the Right Gu REAL WORLD FIX A new four door sport sedan had been aligned several times at the dealership in an attempt to solve a pull to the right The car had front wheel drive and four wheel independent suspension The dealer rotated the tires and it made no difference The alignment angles of all four wheels were in
32. g a vehicle equipped with an electronic suspension several additional steps may be required Always check service information and read carefully all on screen instructions on the alignment machine some examples of the steps that may be needed include Verify the exact type of electronic suspension This step could include checking the regular production order RPO code Check that the ride height suspension height is within factory specifications The steering wheel angle as well as the radar cruise control sensor will often need to be recalibrated using a scan tool Automotive Chassis Systems 5 e Copyright 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved ALIGNING MODIFIED VEHICLES If different springs were installed which in turn changes the suspension height or if larger or smaller wheels and tires were installed many alignment shops would reject doing an alignment If a shop attempted to align a vehicle handling and tire wear problems were common Because the ride height is changed from stock factory setting the following can occur The steering axis inclination SAI is now incorrect Because the steering linkage and the control arms are no longer parallel bump steer can occur Bump steer causes the vehicle to dart to one side when a wheel hits a bump Because the ride height changed camber and toe also changed The camber
33. he datum plane is the horizontal plane Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 E 1995 P rSa Educ qu Inc By James D Ha Upper Saddle r NJ o7aes LAIT rights reserved HIDDEN STRUCTURAL DAMAGE DIAGNOSIS FRAME BODY DIAGONALS FIGURE 34 46 Jig holes used at the assembly plant to locate suspension and drivetrain components Check service information for the exact place to measure and the specified dimensions when checking for body or frame damage Automotive Chassis Systems 5 e Copyright 2010 2008 2004 2000 1995 Pearson Education Inc Upper Saddle River NJ 07458 All rights reserved By James D Halderman TSBs Can Save Time TECH TIP Technical service bulletins TSBs are issued by vehicle and aftermarket manufacturers to inform technicians of a situation or technical problem and give the corrective steps and a list of parts needed to solve the problem TSBs are often released by new vehicle manufacturers to the dealership service department They usually concern the current year vehicle of a particular model While many of these TSBs concern minor problems covering few vehicles many contain very helpful solutions to hard to find problems Automotive Chassis Systems 5 e Copyright 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved TSBs Can Save Time TECH TIP Most TSBs can be
34. ht Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved TOLERANCE ADJUSTMENT PROCEDURE Many vehicles are designed and built without a method to change caster or camber or both Before trying an aftermarket alignment correction kit many technicians first attempt to correct the problem by moving the suspension attachment points within the build tolerance All vehicles are constructed with a slight amount of leeway or tolerance slight corrections can be made because bolt holes are almost always slightly larger than the bolt diameter allowing for slight movement When several fasteners are involved such as where the powertrain cradle subframe attaches to the body of the front wheel drive vehicle a measurable amount of alignment change often over 1 2 degree can be accomplished without special tools or alignment kits Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 E 1995 P rSa Educ qu Inc By James D Ha Upper Saddle r NJ o7aes LAIT rights reserved AFTERMARKET ALIGNMENT METHODS Accurate alignments are still possible on vehicles without factory methods of adjustment by using alignment kits or parts Aftermarket alignment kits are available for most vehicles Even when there are factory alignment methods sometimes the range of adjustment is not enough to compensat
35. logram type steering linkage by turning adjustable tie rod sleeves Special tie rod sleeve adjusting tools should be used that grip the slot in the sleeve and will not crush the sleeve while it is being rotated Automotive Chassis Systems 5 e Copyright 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved Race Vehicle Alignment TECH TIP Vehicles used in autocrossing individual timed runs through cones in a parking lot or road racing usually perform best if the following alignment steps are followed 1 Increase caster 2 Adjust for 1 to 2 degrees of negative camber 3 Set toe to a slight toe out position Copyright 2010 2008 2004 2000 1995 Pearson Education Inc Automotive Chassis Systems 5 e Upper Saddle River NJ 07458 All rights reserved By James D Halderman SETTING TOE FIGURE 34 39 Special tie rod adjusting tools should be used to rotate the tie rod adjusting sleeves The tool grips the slot in the sleeve and allows the service technician to rotate the sleeve without squeezing or damaging the sleeve Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc Automotive Chassis Systems 5 e By James D Halderman Upper Saddle River NJ 07458 All rights reserved CENTERING THE STEERING WHEEL Centerline steering should be accomplished by adjusting the tie rod length on both sides of the vehicle
36. on Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved CHAPTER QUIZ 3 Technician A says that the front toe determines the thrust angle Technician B says that the rear toe angle determines the thrust angle Which technician is correct a Technician A only e Technician B only c Both Technicians A and B a4 Neither Technician A nor B Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc Upper Saddle River NJ 07458 All rights reserved By James D Halderman CHAPTER QUIZ 4 Strut rods if they are adjustable can be used to adjust which angle a oe b Camber c Caster a4 Toe out on turns Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved CHAPTER QUIZ 5 If metal shims are used for alignment adjustment in the front they adjust a Camber ve Caster c Toe a Both a and b Automotive Chassis Systems 5 e Copyright 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved CHAPTER QUIZ 6 Which angle is largest a 0 55 degrees ve 1 4 degree o 45 minutes a 1 2 degree Automotive Chassis Systems 5 e Copyright 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458
37. purchased directly from the manufacturer but the cost is usually very high TSBs can also be purchased through aftermarket companies that are licensed and available on a web site Go to the National Automotive Service Task Force NASTF web site www NASTF org for a list of the web addresses for all vehicle manufacturer s sites where TSBs can be purchased directly Factory TSBs can often save the technician many hours of troubleshooting Automotiv ae is Systems 5 e Copyr sso 2008 2004 Hoe 1995 Pearson Educ Inc id Upper Saddle River NJ 7458 yh ET rved ALIGNMENT GUIDE Problems Pull left right Incorrect steering wheel position Hard steering Loose steering Excessive road shock Poor returnability Wander instability Squeal scuff on turns Excessive body sway Memory steer Bump steer Torque steer Symptom Based Alignment Guide Probable Causes Uneven tire pressure tire conicity mismatched tires unequal camber unequal caster brake drag setback suspension frame sag unbalanced power assist bent spindle bent strut worn suspension components front or rear rear Suspension misalignment Incorrect individual or total toe rear wheel misalignment excessive suspension or steering component play worn rack and pinion attachment bushings individual toe adjusters not provided Improper tire pressure binding steering gear or steering linkage low P S fluid excessive positive caster lack of lubrication
38. r replacing suspension components Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc Automotive Chassis Systems 5 e Upper Saddle River NJ 07458 All rights reserved By James D Halderman Align and Replace at the Same Time TECH TIP Any time a suspension component is replaced the wheel alignment should be checked and corrected as necessary An easy way to avoid having to make many adjustments is to use a magnetic alignment head on the front wheels to check camber with the vehicle hoisted in the air before replacing front components such as new MacPherson struts Then before tightening all of the fasteners check the front camber readings again to make sure they match the original setting This is best done when the vehicle is still off the ground For example a typical front wheeldrive vehicle with a MacPherson strut suspension may have a camber reading of 1 4 degree on the ground and 2 degrees while on the hoist with the wheels off the ground After replacing the struts simply return the camber reading to 2 degrees and it should return to the same 1 4 degree when lowered to the ground Automotive Chassis Systems 5 e Copyright 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved Align and Replace at the Same Time FIGURE 34 2 Magnetic bubble type camber caster gauge To help it keep its strong magnetism it is best to keep
39. rved GUIDELINES FOR ADJUSTING FRONT CAMBER SAI AND INCLUDED ANGLE If the camber is adjusted at the base of the MacPherson strut camber and included angle are changed and SAI remains the same If camber is adjusted by moving the upper strut mounting location included angle remains the same but SAI and camber change Automotiv Pu is Systems 5 e Copyright O 2010 2008 ue E 1995 P Upper Sad Educ gen Te r NJ A LAIT rights reserved GUIDELINES FOR ADJUSTING FRONT CAMBER SAI AND INCLUDED ANGLE STRUT ASSEMBLY LOOSEN TO ADJUSTING ADJUST CAMBER TOOL KNUCKLE Automotive Chassis Systems 5 e FIGURE 34 27 Many struts allow camber adjustment at the strut to knuckle fasteners Here a special tool is being used to hold and move the strut into alignment with the fasteners loosened Once the desired camber angle is achieved the strut nuts are tightened and the tool is removed Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved GUIDELINES FOR ADJUSTING FRONT CAMBER SAI AND INCLUDED ANGLE FIGURE 34 28 Some struts require modification of the upper mount for camber adjustment ELONGATE HOLE STRUT TOWER TOP STRUT MOUNT Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458
40. t the cause by carefully following the prealignment inspection steps and checking for a level powertrain Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved TORQUE STEER STRONGER RIGHT WHEEL STEER TORQUE UNEQUAL DRIVE ANGLES FIGURE 34 8 Broken or defective engine or transaxle mounts can cause the powertrain to sag causing unequal drive axle shaft CV joint angles Automotive Chassis Systems 5 e Copyright 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved ALIGNMENT SPECIFICATIONS Before attempting any alignment consider the following Determine the make model and year of the vehicle Determine if the vehicle is equipped with power steering or manual steering Check the trunk and with the customer to determine the normal load being carried Determine the correct specifications Compensate for the lack of a full gas tank by placing an equal amount of weight in the luggage compartment Determine the correct specifications for the exact vehicle being checked Automotive Chassis Systems 5 e Copyright 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved Keep the Doors Closed but the Window Down TECH TIP An experienced
41. tered Following the procedures for the alignment Autom Miei i equipment determine all alignment angles is Systems 5 e Copyr ea 2008 2004 i 1995 Pea Upper Sadd Educ le River NJ 7458 yh RET 2 Inc rved ALIGNMENT SETUP PROCEDURES INFRARED ALIGNMENT HEAD S ESSI P i FIGURE 34 10 Using the alignment rack hydraulic jacks raise the tires off the rack so that FIGURE 34 11 This wheel sensor has a safety wire they can be rotated as part of the compensating that screws to the valve stem to keep the sensor process from falling onto the ground if the clamps slip on the wheel lip Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved MEASURING CAMBER CASTER SAI TOE AND TOOT CAMBER CASTER SAI TOE DIFFERENCE TOOT STANDARD E OVERSIZE 2 STANDARD TIRE OVERSIZE TIRE Sy FIGURE 34 12 If toe for an oversize tire is set by distance the toe angle will be too small Toe angle is the same regardless of tire size Automotive Chassis Systems 5 e Copyright 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved MEASURING CAMBER CASTER SAI TOE AND TOOT FIGURE 34 13 The protractor scale on the front turn plates allows the technician to test
42. the center of specifications The dealer even switched all four tires from another car in an attempt to solve the problem In frustration the owner took the car to an alignment shop Almost immediately the alignment technician discovered that the right rear wheel was slightly toed in This caused a pull to the right Automotive Chassis Systems 5 e Copyright 2010 2008 2004 E 1995 P r Sa Educ Qua Inc By James D Ha Upper Saddle r NJ idi LAIT rights reserved Left Thrust Line but a Pull to the Right Gu REAL WORLD FIX The alignment technician adjusted the toe on the right rear wheel and reset the front toe The car drove beautifully The owner was puzzled about why the new car dealer was unable to correct the problem It was later discovered that the alignment machine at the dealership was out of calibration by the exact amount that the right rear wheel was out of specification The car pulled to the right because the independent suspension created a rear steering force toward the left that caused the front to pull to the right Alignment equipment manufacturers recommend that alignment equipment be calibrated regularly Automotive Chassis Systems 5 e Copyright 2010 2008 2004 E 1995 P r Sa Educ Qua Inc By James D Ha Upper Saddle r NJ idi LAIT rights reserved Left Thrust Line but a Pull to the Right FIGURE 34 42 The toe in on the right wheel creates a turning force toward the rig
43. tical tire life and fuel economy are maximized and vehicle handling is sure and predictable A complete wheel alignment is a complex process that includes many detailed steps and the skill of a highly trained technician Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved UZAE There are four basic steps in the correction of any problem Verify Isolate Repair the problem Recheck Automotive Chassis Systems 5 e Copyright 2010 2008 2004 2000 1995 Pearson Education Inc Upper Saddle River NJ 07458 All rights reserved By James D Halderman PREALIGNMENT CORRECTION TECHNIQUES FIGURE 34 1 The owner of this Honda thought that all it needed was an alignment Obviously something more serious than an alignment caused this left rear wheel to angle inward at the top s Ads S SSY n AN Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved Align and Replace at the Same Time TECH TIP Magnetic bubble type camber caster gauges can be mounted directly on the hub or on an adapter attached to the wheel or spindle nut on front wheeldrive vehicles Besides being used as an alignment setting tool a magnetic alignment head is a great tool to use wheneve
44. to many sayings in the alignment field Set the toe and let it go Do a toe and go Set the toe and collect the dough Automotiv Pu is Systems 5 e Copyr Ea 2008 2004 i 1995 Pea Educ pu Inc ide Upper Sad dle River NJ 07458 yh RET rved SETTING TOE FIGURE 34 36 Many procedures for setting toe specify that the steering wheel be held in the straight ahead position using a steering wheel lock as shown One method recommended by Hunter Engineering sets toe without using a steering wheel lock Automotive Chassis Systems 5 e Copyright 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved SETTING TOE LOOSEN BOOT josh HOLDING CLAMP TO PREVENT BOOT EN TIE ROD END FROM TWISTING INNER 7 TIE ROD JAM ROTATE SHAFT NUT OUTER DO NOT GRIP TIE ROD THREADS FIGURE 34 37 Adjusting toe by rotating the tie rod on a vehicle equipped with rack and pinion steering Automotive Chassis Systems 5 e Copyright O 2010 2008 2004 2000 1995 Pearson Education Inc By James D Halderman Upper Saddle River NJ 07458 All rights reserved SETTING TOE SLEEVE ROTATING TOOL LEFT HAND SLEEVE RIGHT HAND SLEEVE TURN DOWNWARD TURN UPWARD TURN DOWNWARD TURN UPWARD TO DECREASE TO INCREASE TO INCREASE TO DECREASE ROD LENGTH ROD LENGTH ROD LENGTH ROD LENGTH FIGURE 34 38 Toe is adjusted on a paralle
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