AUMT 1305 - Chassis Systems
Advanced
Introduction
Brake
to Automotive
Systems Diagnosis
Service and Service Introduction to Automotive Service
Tire Identification
• 205/75R15 92H
• 205 - cross sectional
Chassis Systems width in mm
• 75 - aspect ratio
• R - radial construction
Donald Jones • 15 - rim diameter in
Brookhaven College inches
• 92 - load index
• H - speed rating
Introduction to Automotive Service Introduction to Automotive Service
Tire Construction Suspension System
• Tread • Support the weight of
• wear bars the vehicle
• Distribute the load to
• Sidewall each tire
• Bead • Keep the vehicle's
• Body ply wheels in firm contact
• bias verses radial with the road
• Provide a smooth
• Belt comfortable ride
• Inner liner
Introduction to Automotive Service Introduction to Automotive Service
Non-
Non-Independent Suspension Independent Suspension
• Solid axle • Allow each wheel on
suspended by leaf an axle to move
or coil spring at independently of the
each end other wheel
• Reliable
• Light weight
• High load capacity
• Improved ride quality
• Common on trucks
and SUVs • Improved handling
• Used for front and • Used for front and
rear suspension rear suspension
1
AUMT 1305 - Chassis Systems
Introduction to Automotive Service Introduction to Automotive Service
Steering System Steering System Types
• The steering system • Rack and pinion
allows the driver to • Light weight
control the direction of
the vehicle • Compact design
• A series of linkages • Recirculating ball
connect the steering • Minimal internal
wheel to the wheels and friction
tires • Road shock isolation
• Power steering uses • Commonly used on
hydraulics or fluid full size trucks, SUVs
pressure to reduce and cars
steering effort
Introduction to Automotive Service Introduction to Automotive Service
Rack and Pinion Steering Recirculating Ball Steering
• The rack is a rod with • Five major
gear teeth cut along
one side components
• The rack meshes with • Housing
the teeth of a small • Worm shaft
pinion mounted at the • Ball nut
end of the steering shaft
• Recirculating balls
• The steering shaft runs
through the steering • Sector or cross-shaft
column to the steering • Uses parallelogram
wheel
steering linkage
Introduction to Automotive Service Introduction to Automotive Service
Steering Gear Ratios Alignment Angles
• Steering ratio refers • Proper alignment
to the number of provides for vehicle
degrees of driver control and minimal
input in relationship tire wear
to the number of • Three angles are
degrees of tire commonly
adjustable
movement
• Caster
• Fast ratio
• Camber
• Variable ratio • Toe
2
AUMT 1305 - Chassis Systems
Introduction to Automotive Service Introduction to Automotive Service
Caster Caster
• The forward or • The forward or
rearward tilt of the rearward tilt of the
steering axis as steering axis as
viewed from the side viewed from the side
of the vehicle of the vehicle
• Neutral • Neutral
• Negative
Introduction to Automotive Service Introduction to Automotive Service
Caster Camber Angle
• The forward or • Inward or outward tilt of
rearward tilt of the the tire when viewed
from the front of the
steering axis as
vehicle
viewed from the side • True vertical is referred
of the vehicle to as zero camber or
• Neutral camber neutral
• Negative
• Positive
Introduction to Automotive Service Introduction to Automotive Service
Camber Angle Camber Angle
• Inward or outward tilt of • Inward or outward tilt of
the tire when viewed the tire when viewed
from the front of the from the front of the
vehicle vehicle
• True vertical is referred • True vertical is referred
to as zero camber or to as zero camber or
camber neutral camber neutral
• An inward tilt is referred • An inward tilt is referred
to as negative camber to as negative camber
• An outward tilt is referred
to as positive camber
3
AUMT 1305 - Chassis Systems
Introduction to Automotive Service Introduction to Automotive Service
Toe Toe
• Measurement of the • Measurement of the
difference in difference in
distance between distance between
the front of the tires the front of the tires
and the rear of the and the rear of the
tires tires
• Zero toe • Zero toe
• Toe in or positive toe
Introduction to Automotive Service Introduction to Automotive Service
Toe Brake System Components
• Measurement of the • Master cylinder
difference in • Brake lines
distance between • Hydraulic valves
the front of the tires
and the rear of the • Disc brakes
tires • Drum brakes
• Zero toe • Power assist unit
• Toe in or positive toe • Parking brake
• Toe out or negative
toe
• Antilock brake system
Introduction to Automotive Service Introduction to Automotive Service
Brake Hydraulic System Disc Brakes
• Master cylinder • Floating and fixed
• Brake system valves caliper designs
• Metering valve
• Proportioning valve • Fade resistant
• Pressure differential valve design
• Combination valve • Self adjusting
• Calipers
• Major components
• Wheel cylinders
• Rotor
• Hydraulic circuits
• Caliper assembly
• Front-Rear split
• Diagonally split • Brake pads
4
AUMT 1305 - Chassis Systems
Introduction to Automotive Service Introduction to Automotive Service
Drum Brakes Antilock Brakes
• Duo servo and • The electronic
leading trailing control unit monitors
designs brake pedal
• Major components application and
• Brake drum wheel speed
• Brake shoes
• Solenoids are used
• Wheel cylinder
• Backing plate
to limit and/or
• Springs and reduce brake apply
installation hardware pressure
