The rack and pinion gear assembly is a complete device consisting of two parts: a rack and a pinion. Specifically, the rack is a straight gear with a row of evenly spaced teeth, typically in a straight configuration; the pinion is a round gear with a tooth profile that matches the rack.

The hydraulic system's oil pipes are responsible for transporting hydraulic fluid to the rack and pinion assembly. If cracks or ruptures occur in the pipes due to aging, wear, or collision, hydraulic fluid can leak through the damaged areas. Additionally, loose joints and poor seals at the oil line connections can also cause fluid leaks.