Suspension Systems - 1 Topics covered in this presentation: Basic Suspension System Spring Types Suspension System Construction

Elementary Suspension System Suspension system supports the weight of vehicle and gives a smooth ride. Control arm pivots on frame. Steering knuckle ball-jointed to control arm. Coil spring and shock absorber shown. Components attached to frame. Next >

Question 1 Which of the following is a purpose of a suspension system? A) To make the steering work smoothly B) To connect the wheels to the tyres Correct Answer = C C) To give a smooth ride D) To help the wheels turn smoothly

Independent Suspension Solid axle - tilts with road bumps. Both wheels tilted. Independent suspension - one wheel moves without affecting other. Control arm pivots, this helps to keep the wheel upright. Preferred system for modern vehicles. Next >

Coil Spring Four main types of spring: Coil Spring Leaf Spring Torsion Bar Air Spring Coil Spring Spring-steel rod wound into coil. Suited to independent suspension. Most common. Next >

Leaf Spring Flat spring steel plates. Front end pivot fixed to frame. Swinging shackle at rear permits change of length. U-bolts and plates clamp spring to axle housing. Now only used on few rear suspension systems. Next >

Torsion Bar Torsion bar attached to vehicle frame. Control arm attached to torsion bar. Torsion bar Strut rod keeps control arm stable. When control arm moved, torsion bar resists movement. Steering knuckle ball joint attaches to control arm. Next >

Air Spring Two-ply rubber cylinder filled with compressed air. Similar rebound action to coil spring. Lighter weight. Rebound allows for hollows in road surface. Adaptable to automatic levelling systems. Next >

Question 2 Which spring system is now usually only used on rear suspension systems? A) Torsion bar B) Air spring Correct Answer = D C) Coil spring D) Leaf spring

Question 4 What does an air spring contain? A) Compressed air B) A vacuum Correct Answer = A C) Two-ply rubber D) A coil spring

Control Arm Control arm Steering knuckle Holds the steering knuckle, bearing support or axle housing. Connected by ball joint. Bushes Bushes act as bearings. Free to move up and down with suspension. Ball joint Rear suspension - may have bushes both ends. Next >

Question 5 What connects the control arm to the steering knuckle? A) Bushes B) Ball joint Correct Answer = B C) Bearings D) Spring

Control Arm and Strut Rod Used with independent suspension. Control arm attached to cradle or frame. Other end to steering knuckle. Strut rod prevents movement of control arm. Rubber bushes soften action and absorb shocks. Next >

Ball Joints Ball-and-socket joint. Limited movement in all directions. Drive shaft Steering knuckle Lower ball joint Upper ball joint Hub Limited movement in all directions. Pivots keep wheel vertical. Front wheel - Steering knuckle. Drive shaft must allow movement. Next >

Question 6 What delivers the drive to the wheels? A) Drive shaft B) Control arm Correct Answer = A C) Steering knucke D) Ball joints

Shock Absorber Reduce spring oscillations. Upper end attached to frame, lower end to suspension unit. Piston and valve assembly moves in oil-filled cylinder. Movement is controlled by valve restriction. Some have pressurized gas chamber that reduces air bubbles. Enclosed in dust cover. Next >

Question 7 What is the purpose of a shock absorber? A) To prevent steering wheel bounce B) To support the wheel Correct Answer = D C) To reduce air bubbles D) To reduce oscillations

MacPherson Strut Shock Absorber Combined spring and shock absorber. Upper pivot is strut mount. Bearing to allow steering. Bump stops or rebound bumpers prevent metal/metal contact. Shock absorber inside strut. Lower spring seat on shock absorber body. Metal strut tube houses shock absorber reservoir, valve, pressure tube etc. Next >

Stabilizer (Sway) Bar Prevents excessive body lean when turning. Links both the lower control arms together. When cornering, outside of body drops and twists the bar to limit sway. Stabilizer bar Next >

Question 8 What links both the lower control arms together? A) Panhard rod B) Stabilizer bar Correct Answer = B C) Torsion bar D) Control bar

Panhard Rod Prevents rear axle lateral movement. Support bracket Diagonal brace Rear (solid) axle Panhard rod Prevents rear axle lateral movement. One end connected to frame of vehicle. Other end fastened to axle. End >