When the rack and pinion system fails, the vehicle's driving trajectory may be abnormal. For example, the vehicle may deviate from the straight driving trajectory even if the steering wheel is in the neutral position.

They are not the same concept. Rack and pinion is a specific mechanical structure responsible for converting the rotation of the steering wheel into the steering of the wheels; while power steering is an auxiliary system designed to reduce the amount of effort required by the driver during steering.

Spur gears are the most common type of gears, with a straight tooth shape and a tooth surface parallel to the rotation axis of the gear. Spur gears are mainly used to transmit power between parallel axes. In a rack and pinion system, spur gears usually mesh with racks to convert rotational motion into linear motion.

Although rack and pinion steering systems are very popular in ordinary road vehicles, their application in NASCAR cars is relatively limited. NASCAR cars generally do not use rack and pinion steering systems, but continue to rely on recirculating ball steering systems.

Positive locking means that in a rack and pinion steering system, a specially designed locking device is used to automatically lock or limit the steering angle under certain conditions to prevent the vehicle from oversteering or steering out of control.

Although rack and pinion steering systems are still widely used in passenger cars and small commercial vehicles, other types of steering systems, such as recirculating ball steering systems and Electric Power Steering (EPS) systems, have gradually taken over the market in some high-end models, heavy vehicles and off-road vehicles.

In response to the question of "Can you replace only the rack without replacing the pinion?", the answer is usually no. This is not only because the two are closely connected in mechanical structure, but more importantly, replacing the rack or pinion alone may cause a series of problems, affecting the overall performance and safety of the steering system.

If your vehicle is equipped with a hydraulic power steering system, first check the level of the steering hydraulic fluid. If the level is too low, there may be an oil leak, which is usually one of the signs of a damaged steering rack gear.

Power steering leak stopper is a common commercial product that usually fills the leak point by adding a chemical to the power steering fluid, especially the aging or cracks of the seal. Leak-stopping agents work by forming a hardened film of chemicals at the leak point through contact with air or temperature, sealing the leaking fluid and slowing or stopping the leak.

In 1965, Ford introduced the Ford Mustang, which became the first mass-produced American model to widely adopt rack-and-pinion steering. The launch of the Ford Mustang marked an important step for American automakers in steering technology and also represented the increasing demand for better handling in the U.S. market.