In this FAQ I'll be covering ball joints, tie rods, wheel bearings, struts, shocks, springs, sway bars, steering racks (though not conventional steering with pitman arms like those on Jeep Wranglers, Ford trucks, and so on), lightly touch on wheels and tires.

Ball Joints

Ball joints control the wheel's ability to tip left or right, or preferably not to tip at all with good ball joints.
To check for ball joints; raise the front wheels off of the ground (raise the rear wheels if checking rear ball joints) making sure to set the emergency/parking brake and chock the back wheels.
Now, with one hand on the top of the wheel and one hand on the bottom of the wheel, move it back and forth. If you feel any abnormal play in the wheel, your ball joint is bad.
On the road, this can make the car "wander", have a slight clunking noise, depending on how bad your ball joint is.
Example: You're taking a long sweeping right-hand turn at highway speeds and hit a bump or pothole, which really doesn't have to be that big or deep, in the road. Right away, you don't notice anything, but as you begin to come to a straightaway, you notice that the car now pulls to either the left or the right. Further on, you hit another bump and now it pulls the opposite direction. This would lead you to bad ball joints for starters.
When you remove the ball joint from the LCA (Lower Control Arm, no, we don't have UCA) the ball joint should feel somewhat hard to turn by itself. There should be enough resistance that it won't allow you to turn it easily. If you can twist it, move it side to side, then you should look at replacing it soon!

Symptoms of Worn Ball Joints
1. "Wandering" on a straight, level, smooth road.
2. Lots of play in the ball joint.
3. Torn ball joint boot.
4. Vertical tire movement.

Tie Rods

Tie rods control the toe of the vehicle, positive and negative. Front wheel drive vehicles have an amount of toe-out (positive toe). Toe-ing out the vehicle allows it to drive more straight down the highway without much correction and decreases the vehicle's ability to turn sharply and quickly given the front wheels are "pulling" against one another.
Checking the amount of wear on the tire is a good indication of a bad toe angle. If there is wear on the inside of the tire(s) and a feathered edge leading to the outside of the tire(s) there is most likely too much toe-out. The opposite is true for too much toe-in.
To check for bad tie rods, with the front of the car in the air and the rear wheels chocked, place your left hand on the left side of the tire and your right on the right-hand side of the tire. Move the tire back and forth taking into account for steering rack movement. If by the end of the steering rack movement you feel the wheel shift some more by a slight amount, chances are your tie rod is bad and may need to be replaced.

Symptoms of Worn Tie Rods
1. Worn inside of tire with feathered edge leading to outside or worn outside of tire with feathered edge leading to inside of tire.
2. "Wobbling" feeling traveling down the road usually at a slower speed depending on the amount of wear the tie rod has.

Wheel Bearings

Wheel bearings allow your tire to roll smoothly in a straight line. There is no adjustment of the wheel bearings; they are either good or bad. Every vehicle has wheel bearings. On our vehicles, the wheel bearings are located within the hub, behind the brake rotors.
Wheel bearings are known to be bad when there is a grinding sound coming from the wheels (when known that the brakes are fine), leaking grease from the bearing itself, uneven tire wear like that of ball joints and tie rods. To check for bad wheel bearings, lift the front (or if the back bearings are suspected, the rear of the vehicle), chock the rear wheels. Move the wheel from side to side, and back and forth. If movement is felt in both areas, chances are you've got bad wheel bearings. To check even further, slowly spin the wheel and feel for any harshness in the movement and listen for any grinding.

Symptoms of bad Wheel Bearings
1. Tire wear which includes, but is not limited to, that of bad tie rods and bad ball joints.
2. Grinding noise coming from wheel hub.
3. Grease from the bearing itself is leaking out of the hub assembly.

Struts and Shocks

Struts and shocks control jounce and rebound of the car while it's traveling over bumpy roads. Jounce is the downward movement of the piston in the strut or shock housing. Rebound is the exact opposite; it 'lifts' the car back into it's normal specified ride height.

Symptoms
When struts and shocks go bad, they tend to not have enough jounce and rebound left in them so it leaves the vehicle's ride height compensated; it will not sit as high as factory specifications or as high as what the vehicle has been originally lowered to.
Bad struts and shocks always lead to bottoming out over bumps within the road.

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DSM: Defeating the purpose of financial management since 1989.

Contact:
CaffeineTripp AIM/MSN/Y!M
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On my way to ASE Certification.

Great write-up!

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And it'll only get longer!

_________________
DSM: Defeating the purpose of financial management since 1989.

Contact:
CaffeineTripp AIM/MSN/Y!M
7634649788 SMS
On my way to ASE Certification.