brakes
Post on 11-Sep-2014
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TypesTypes
Parking BrakeService Brake
HydraulicDisc BrakesDrum BrakesDual System
Antilock Brake System (ABS)
Parking BrakeService Brake
HydraulicDisc BrakesDrum BrakesDual System
Antilock Brake System (ABS)
Play Principles of Braking
Play Principles of Braking
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Brake System Principles
Brake System Principles
Kinetic Energy
Mass Weight Speed Inertia and Momentum
Kinetic Energy
Mass Weight Speed Inertia and Momentum
Coefficient of Friction VideoCoefficient of Friction Video
Parking BrakeParking 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
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
Typical Parking BrakeTypical Parking Brake
Play Parking Break Video
Play Parking Break Video
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Play Parking Brake Adjustment Video
Play Parking Brake Adjustment Video
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Service BrakesService 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
Primary Braking System Should be stronger than the engine
Hydraulic Operated Can be Vacuum, Hydro or Motor assisted
Disc System Drum System Dual System
Typical SystemTypical System
Hydraulic PrinciplesHydraulic 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
Force
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
Force
AreaPressure
HydraulicsHydraulicsSimplified Hydraulic Brake System
Drum BrakeMaster CylinderDisk Brake
Simplified Hydraulic Brake System
Drum BrakeMaster CylinderDisk Brake
Hydraulic pressure is distributed equally in
all directions
Hydraulic pressure is distributed equally in
all directions
Same line pressure to Same line pressure to all wheelsall wheels
Same line pressure to Same line pressure to all wheelsall wheels
The Hydraulic pressure is The Hydraulic pressure is the same, but the applied the same, but the applied force can be changed by force can be changed by
thethe piston size piston size
The Hydraulic pressure is The Hydraulic pressure is the same, but the applied the same, but the applied force can be changed by force can be changed by
thethe piston size piston size
The applied The applied pressure can pressure can be raised or be raised or lowered by lowered by piston sizepiston size
The applied The applied pressure can pressure can be raised or be raised or lowered by lowered by piston sizepiston size
Play Hydraulic Pressure VideoPlay Hydraulic Pressure Video
Brake Pedal DesignAdvantage by LeverageBrake Pedal DesignAdvantage by Leverage
First Mechanical Advantage is Driver’s foot
Length of Lever determines force applied
Uses Fulcrum Pedal Ratio
First Mechanical Advantage is Driver’s foot
Length of Lever determines force applied
Uses Fulcrum Pedal Ratio10
25:1 2.5 inches
50.5 inch
Play Break Pedal Leverage VideoPlay Break Pedal Leverage Video
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System BasicsSystem BasicsHydraulic actuation allows multiplication of pedal force.
In this system, a 10lb force on the pedal produces 360 lbs of force at the friction surface.
Hydraulic actuation allows multiplication of pedal force.
In this system, a 10lb force on the pedal produces 360 lbs of force at the friction surface.
Play Break Lines & Hose Video
Play Break Lines & Hose Video
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Brake FluidBrake Fluid
Properties of Brake FluidDoes not thicken or then with changing heat
Must not boilMust be compatible with brake parts material
Must lubricate internal partsMust not evaporate easily
Properties of Brake FluidDoes not thicken or then with changing heat
Must not boilMust be compatible with brake parts material
Must lubricate internal partsMust not evaporate easily
Brake Fluid typesBrake Fluid types
DOT 3 and 4- Polyglycol based
Most common Compatible with one another
Inexpensive Destroys paint Ruined by moister
DOT 3 and 4- Polyglycol based
Most common Compatible with one another
Inexpensive Destroys paint Ruined by moister
DOT= Department of TransportationHigh #= High stands, quality and boiling point
• DOT 5- • Silicone Based• Used only for heavy
duty applications
• Not Compatible with 4&5
• Very Expensive• Does not damage
paint
• DOT 5- • Silicone Based• Used only for heavy
duty applications
• Not Compatible with 4&5
• Very Expensive• Does not damage
paint
Fluid ContaminatesFluid Contaminates
Moister- Lowers boiling point water boils @ 212*F DOT 3 boils @ 401*F
Petroleum Based Product- soften rubber parts causing swelling
Dirt & Debris- causes corrosion and clogs
Air and Vapors- Compressible prevents pressure from reaching brakes
Moister- Lowers boiling point water boils @ 212*F DOT 3 boils @ 401*F
Petroleum Based Product- soften rubber parts causing swelling
Dirt & Debris- causes corrosion and clogs
Air and Vapors- Compressible prevents pressure from reaching brakes
Play Break Fluid VideoPlay Break Fluid Video
Master CylinderMaster Cylinder
Provides a reservoir for brake fluid and contains the driving pistons in the hydraulic circuit
2 TypesFront - Rear split -One piston for front brakes and one for rear-If a leak occurs you could lose front brakes
Diagonally split -One piston drives one front wheel and one rear wheel-Diagonal layout allows you to maintain directional control if a leak occurs
Provides a reservoir for brake fluid and contains the driving pistons in the hydraulic circuit
2 TypesFront - Rear split -One piston for front brakes and one for rear-If a leak occurs you could lose front brakes
Diagonally split -One piston drives one front wheel and one rear wheel-Diagonal layout allows you to maintain directional control if a leak occurs
Play Tandem Master Cylinder Video
Play Tandem Master Cylinder Video
Play Divide System Video
Play Divide System Video
Power Booster in closed positionPower Booster in closed position
Play Power Booster Video
Play Power Booster Video
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Drum BrakesDrum Brakes Expanding shoes create force on the inner surface of the drum
Used on the rear of some trucks and SUV’s
Self-energizing design requires less activation force
Require periodic adjustment
Expanding shoes create force on the inner surface of the drum
Used on the rear of some trucks and SUV’s
Self-energizing design requires less activation force
Require periodic adjustment
Drum Brake SystemDrum Brake System
Vented RotorsVented Rotors
Vented Rotors have Fins in the spaces between their machined surfaces. These spaces allow air to pass through, which helps carry heat away.
Nonvented RotorNonvented RotorNon Vented Rotors are used on smaller vehicles, and have no cooling fins
Play Brake Disc VideoPlay Brake Disc Video
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Disc Brake Caliper Assembly
Disc Brake Caliper Assembly
Caliper TypesCaliper TypesThere are 2 types of CalipersFixed
Calipers are disc brakes that use a caliper that is FIXED in position and does not slide. They have pistons on both sides of the disc. There may be 2 or 4 pistons per caliper
Floating Much more common Single Piston Easier to work with On “inboard” side of caliper
There are 2 types of CalipersFixed
Calipers are disc brakes that use a caliper that is FIXED in position and does not slide. They have pistons on both sides of the disc. There may be 2 or 4 pistons per caliper
Floating Much more common Single Piston Easier to work with On “inboard” side of caliper
Fixed CaliperFixed Caliper
•Motorcycles and some import trucks and cars use this type
•Similar to bicycle brakes
Sliding CaliperSliding Caliper
Applies pressure to two pads on opposite sides of rotor
Caliper Sliding Fixed
Friction Material exposed to air
Applies pressure to two pads on opposite sides of rotor
Caliper Sliding Fixed
Friction Material exposed to air
Fixed CaliperFixed Caliper
Applies two pistons to opposite sides of rotor
Caliper stays stationary
Disc Brakes require higher hydraulic pressure
Applies two pistons to opposite sides of rotor
Caliper stays stationary
Disc Brakes require higher hydraulic pressure
Play Disc Brake Calipers VideoPlay Disc Brake Calipers Video
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DiagnosisDiagnosis
Several different types of Complaints
Noise
Pulsation
Pedal travel
More later…
Brake NoiseBrake Noise
Wear Indicator
Brake PulsationBrake Pulsation
Usually a warped Rotor
Rotor needs trued on a brake lathe
Pedal TravelPedal Travel
NO BRAKES!!!!
•Excessive pedal travel
•Pedal feels soft and squishy
•Requires excessive effort to stop vehicle or my cause brakes to not function at all
Play Drum Brake Inspection VideoPlay Drum Brake Inspection Video
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Play Disc Brake Inspection VideoPlay Disc Brake Inspection Video
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Anti-Lock BrakesAnti-Lock Brakes A locked (sliding) wheel offers less braking force than a decelerating rolling wheel
The locked wheel also produces little lateral force, preventing steering control
Anti-Lock systems (ABS) monitor wheel lock-up and modulate brake pressure to provide controlled braking under most circumstances
A locked (sliding) wheel offers less braking force than a decelerating rolling wheel
The locked wheel also produces little lateral force, preventing steering control
Anti-Lock systems (ABS) monitor wheel lock-up and modulate brake pressure to provide controlled braking under most circumstances
Play ABS Principles Video
Play ABS Principles Video
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Anti-Lock BrakesAnti-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
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
Play ABS videoPlay ABS video
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Play Drum, Disc, & ABS Video
Play Drum, Disc, & ABS Video
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Other Braking SystemsOther Braking Systems
Air BrakesExhaust BrakesElectric or Trailer Brake
Air BrakesExhaust BrakesElectric or Trailer Brake
Play Disc Brake Replacement VideoPlay Disc Brake
Replacement Video
Play Replacing The Rotor VideoPlay Replacing The Rotor Video
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Play Drum Brake Replacement VideoPlay Drum Brake
Replacement Video
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