30-03-2012, 02:09 PM
Brakes system
brakes.ppt (Size: 1.15 MB / Downloads: 78)
Parking Brake
Not an “Emergency” Brake
Used specifically to keep a parked vehicle from moving
Usually on rear wheels only
Mechanically operated
Static Friction: at rest friction- More friction
Kinetic Friction: in motion friction- less friction
Service Brakes
Primary Braking System
Should be stronger than the engine
Hydraulic Operated
Can be Vacuum, Hydro or Motor assisted
Disc System
Drum System
Dual System
Hydraulic Principles
Fluids cannot be compressed
Fluids can transmit Movement
Acts “Like a steel rod” in a closed container
Master cylinder transmits fluid to wheel cylinder or caliper piston bore.
Fluids can transmit and increase force
Brake Fluid
Properties of Brake Fluid
Does not thicken or then with changing heat
Must not boil
Must be compatible with brake parts material
Must lubricate internal parts
Must not evaporate easily
Anti-Lock Brakes
System can have 2, 3 or 4 channels
Trucks typically use 3 channel with only one sensor for the rear axle
Most modern cars use 4 channel system
Wheel speed sensors monitor each wheel speed
ABS controller and high-pressure pump increase or reduce pressure to wheels in order to maintain consistent wheel speeds