Sample Review Questions:
1. Counterman A says sealed “low friction” ball joints with polymer bushings and polished ball studs are used in most late-model vehicles to reduce friction and steering effort. Counterman B says if the “wear indicator” on a ball joint is flush with the housing, it means the joint is new. Who is right?
a. Counterman A only
b. Counterman B only
c. Both Counterman A and B
d. Neither one
2. Which of the following components should be replaced if a vehicle’s ride height is below specifications?
a. Tie rod ends
b. Ball joints
c. Control arm bushings
d. Springs
3. Which of the following components will cause rapid toe wear on the front tires if worn or loose?
a. Tie rod ends
b. Ball joints
c. Control arm bushings
d. Shocks absorbers or struts
4. Counterman A says gas charged shocks contain high-pressure gas to help support the vehicle’s weight. Counterman B says preassembled MacPherson struts include new upper bearing plates and springs. Who is right?
a. Counterman A only
b. Counterman B only
c. Both Counterman A and B
d. Neither one
ANSWER KEY
1A, 2D, 3A, 4B
EXPLANATIONS:
1. Ball joints are used to connect the control arms to the steering knuckle. Suspensions with upper and lower control arms have four ball joints (two upper and two lower). Strut suspensions usually have only two lower ball joints, though some may also have an upper wishbone control arm with one or more ball joints. Ball joints may also be used in the rear suspension on some FWD cars.
A ball joint has a stud that rides against a bearing. The ball joints in most late-model passenger car and light truck have plastic (polymer) bearings that are lubed for life and have no grease fitting. Older vehicles and some trucks have ball joints with metal gusher bearings that do require periodic greasing. Some ball joints have built-in wear indicators that protrude from the housing when the joint is new. As the joint wears, the indicator recedes into the housing. When the indicator is flush with the housing, it’s time to replace the joint.
2. Tie rod ends are part of the steering linkage, while ball joints and control arm bushings are part of the suspension but have nothing to do with ride height. It’s the springs that carry the weight and determine ride height. Coil springs, leaf springs and torsion bars can all sag with age, causing a loss of ride height that adversely affects wheel alignment. Sagging coil and leaf springs should be replaced if ride height is less than specifications. Torsion bars, however, can usually be adjusted to restore ride height.
3. The tie rod ends connect the steering linkage to arms on the steering knuckles or struts. If the tie rod ends are worn, they can cause steering looseness and rapid toe wear on the front tires. Worn ball joints or control arm bushings can also cause tire wear, but it is typically shoulder wear (camber wear) on the edge of the tire. Worn shocks or struts can produce cupped wear on the tires.
4. The gas charge inside a shock absorber or strut is there to prevent fluid foaming and aeration when the shock is pumping up and down rapidly. Foaming reduces the resistance inside the shock, and causes a loss of ride control called shock fade. Preassembled struts have become a popular alternative to rebuilding old struts because they are faster and easier to install. The preassembled units come complete with new upper bearing plates and springs, items which are often overlooked when replacing struts, and may cause problems down the road unless they are in good condition.
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