The inner and outer tie rod ends on a car connect the steering rack or parallelogram steering linkage to the knuckles on the front axle. Tie rods are designed to allow limited flexibility, allowing the knuckle to turn back and forth with a tire moving forward or backward on it. When the tie rod connection to the steering rack or to the knuckle becomes compromised, it can lead to erratic steering and damage other components, such as the tires.
Test drive the vehicle to ascertain if there is any vibrating when driving (not braking) or any clunks are heard when taking corners. A loose tie rod connection will allow the tire to wobble on its axis. This wobble will be felt in the steering wheel in addition to the entire front axle, as it will transfer across. A clunking when turning could be indicative of a loose tie-rod-end-to-knuckle connection. Movement of the knuckle under duress can allow excessive movement in the connection, creating a metal-to-metal contact.
Park the car on a flat, paved surface and lift one front end up with a floor jack. Place a jack stand safely and securely below the vehicle to support it.
Recruit a helper to watch or hold the tie rod connection while you manipulate the tire--or the other way around if you want to check the tie rod. Place your hands at 3 and 9 o'clock on the tire and wiggle it with short back-and-forth movement. Most passenger cars that are front-wheel drive have a strut suspension attached to the knuckle and allow very little to no movement in each individual knuckle assembly. If you're checking for movement and detect some, be sure that you're looking at the lower ball joint as well as the bearing assembly. In outer tie rod end connections, the ball socket of the tie rod shaft can move in the knuckle connection or wiggle up and down where it connects to the inner tie rod. If movement is felt but cannot be seen, reposition your hand on the inner tie rod and wiggle the tire again. An inner tie rods connection to the steering rack is internal and cannot be seen. If the movement feels more excessive with your hand on the inner tie rod, then it is bad.
Wiggle the tire in the same fashion, but hold your hands at 6 and 12 o'clock. A tie rod end connection will not cause movement this way, but a bad bearing assembly or an excessively worn ball joint can. This will help you determine if the movement is being transferred from another loose component.
Use a grease gun to fill any grease fittings on the ball joint and tie rod ends. Although many cars today have unserviceable chassis components--meaning they're sealed with permanent lubrication--some aftermarket replacement parts still use them. If grease fittings are present, fill the components with grease until the rubber boots swell and then retry the back and forth wiggle movement of the tire. Lack of grease in a tie rod end or ball joint can allow very slight movement, which can be determined if it tightens up by filling it with grease. While this may solve a temporary problem, the component will eventually need to be replaced.
Lower the vehicle on the side its one and then repeat the procedure for the other side.