Automotive Workshop Practice 1 Report_Alignment

Title: Alignment Introduction A wheel alignment is the adjustment of the suspension and steering component angles to ensure proper vehicle handling with minimum tire wear. When a vehicle is new, the alignment angles are set at the factory. After many miles and/or months of driving, the alignment angles can change slightly. The change in alignment angles may result from one or more of the following conditions: 1. Wear of the steering and the suspension components 2. Bent or damaged steering and suspension parts 3. Sagging springs, which can change the ride height of the vehicle and therefore the alignment angles By adjusting the suspension and steering components, proper alignment angles can be restored. An alignment includes checking and adjusting, if necessary, both front and rear wheels. Maintaining proper alignment is fundamental to preserving both car’s safety and its tread life. Wheel alignments ensure that all four wheels are consistent with each other and are optimized for maximum contact with the surface of the road. The way a wheel is oriented on car is broken down to three major components; camber, caster, and toe.

Objective 1. Able to carry out wheel alignment 2. Able to explain how camber, caster, and toe affect the handling and tire wear of the vehicle 3. Able to use equipment properly for wheel alignment

Equipment 1. 2. 3. 4. 5. 6.

Alignment machine Wheel sensor Turn plates Screwdriver Ring wrench Set spanners

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Procedure Procedure

Diagram

1. Begin the alignment procedure by first driving the vehicle onto the alignment rack as straight as possible.

2. Position the front tires in the center of the turn plates. These turn plates can be moved inward and outward to match a vehicle of any width.

3. Raise the vehicle and position the alignment rack following the rack manufacturer’s instructions.

4. Check and adjust tire pressures and perform the prealignment checks necessary to be assured of proper alignment.

5. Select the exact vehicle on the alignment machine.

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6. Securely mount the alignment heads or target wheels.

7. If mounting a transmitter-type alignment head, be sure to attach the retaining wire to the tire valve.

8. After installation of the heads, follow the specified procedure for compensation, which allows accurate alignment readings.

9. Rolling compensation is used on machines that use lasers and wheel targets.

10. An alignment reading is displayed even though caster has not yet been measured. The readings marked in red indicate that they are not within specifications.

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11. Before performing a caster sweep, install a brake pedal depressor to keep the front wheels from rotating when the steering wheel is turned.

12. Perform the caster sweep by turning the front wheels inward, and then outward following the instructions on the screen.

13. Most alignment machines will display where to make the alignment correction and will often include drawings and live-action videos that show the procedure.

14. The rear toe is being adjusted by rotating the eccentric cam on the lower control arm while watching the display.

15. The alignment machine display indicates that front caster is not a factory-adjustable angle.

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16. Adjusting the front toe on this vehicle involves loosening the jam nut (left wrench) and rotating the tie rod using the right wrench.

17. One last adjustment of the left front toe is needed to achieve a perfect alignment. The final alignment reading can be printed and attached to the work order.

18. After disconnecting all of the attachments, reinstalling the valve caps, and removing the steering wheel holder, the vehicle should be test driven to check for proper alignment before returning it to the customer.

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Discussion Explain how camber, caster, and toe affect the handling and tire wear of the vehicle. 1. Pull. A pull is generally defined as a definite tug on the steering wheel toward the left or the right while driving straight on a level road. Bent, damaged, or worn suspension and/or steering components can cause this problem, as well as a tire problem.

A pull is usually defined as a tug on the steering wheel toward one side or the other.

2. Lead Or Drift. A lead or drift is a mild pull that does not cause a force on the steering wheel that the driver must counteract. A lead or drift is observed by momentarily removing your hands from the steering wheel while driving on a straight, level road. When the vehicle moves toward one side or the other, this is called a lead or a drift.

3. Road Crown Effects. Most roads are constructed with a slight angle to permit water to drain from the road surface. On a two-lane road, the center of the road is often higher than the berms, resulting in a road crown. a. On a four-lane expressway (freeway), the crown is often between the two sets of lanes. Because of this slight angle to the road, some vehicles may lead or drift away from the road crown. In other words, it may be perfectly normal for a vehicle to lead toward the right while being driven in the slow lane and toward the left while being driven in the fast (or inside) lane of a typical divided highway.

The crown of the road refers to the angle or slope of the roadway needed to drain water off the pavement. (Courtesy of Hunter Engineering Company)

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4. Wander. A wander is a condition where constant steering wheel corrections are necessary to maintain a straight-ahead direction on a straight, level road. Worn suspension and/or steering components are the most likely cause of this condition. Incorrect or unequal alignment angles such as caster and toe, as well as defective tire(s), can also cause this condition.

Wander is an unstable condition requiring constant driver corrections.

5. Stiff Steering Or Slow Return To Center. Hard-to-steer problems are commonly caused by leaks, either low tire pressure (due to the leak of air) and/or lack of proper power steering (due to the leak of power steering fluid). Other causes include excessive positive caster on the front wheels or binding steering linkage. 6. Tramp Or Shimmy Vibration. Tramp is a vertical-type (up-and-down) vibration usually caused by out-of-balance or defective tires or wheels. Shimmy is a back-and-forth vibration that can be caused by an out-of-balance tire or defective wheel or by an alignment problem. NOTE: Wheel alignment will not correct a tramp-type vibration.

Conclusion 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 vertical, 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.

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Reference 1. James D. Halderman, Automotive Technology Principles, Diagnosis, and Service, 4th Edition, Pearson Education, 1 Lake Street, Upper Saddle River, New Jersey 07458, 2012. 2. Tom Denton, Automobile Mechanical and Electrical Systems, Elsevier The Boulevard, Langford Lane, Kidlington, Oxford, OX5 1GB 225 Wyman Street, Waltham, MA 02451, USA, 2011. 3. http://yospeed.com/wheel-alignment-explained-camber-caster-toe/

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