The design and main components of mechanical, hydraulic and electric power steering racks, and what to watch for during maintenance.
Today’s passenger cars use rack-and-pinion steering, assisted for comfort by hydraulic (HPS) or electromechanical (EPS) power steering. MSG Equipment explains the three main types:
- Mechanical rack: transfers torque directly from pinion to rack; it comprises an aluminium housing, pinion, spring-loaded pressure piston and tie rod bushing, and is often paired with column EPS.
- Hydraulic rack: adds a hydraulic cylinder between rack and housing and a rotary valve on the input shaft; it needs care against leaks and contamination, and must be bled after refilling.
- Electric rack: an electric motor provides the assistance.