1. Chapter 9: Parking Brakes
Automotive Brake Systems
Chapter 9: Parking Brakes

2. Understand and Describe: The function of parking brakes
Automotive Brake Systems, Sixth Edition
Chapter 9, Parking Brakes
Objectives
Understand and Describe:
The function of parking brakes
Basic types of parking brake systems
Types of parking brake controls
Types of cables used to operate parking brakes
The operation of disc brake and drum brake parking brakes

3. Understand and Describe: The operation of electric parking brakes
Automotive Brake Systems, Sixth Edition
Chapter 9, Parking Brakes
Objectives
Understand and Describe:
The operation of electric parking brakes

4. Parking brakes are designed to hold the vehicle stationary once parked
Automotive Brake Systems, Sixth Edition
Chapter 9, Parking Brakes
Introduction
Parking brakes are designed to hold the vehicle stationary once parked
Should not be called ‘Emergency Brakes’ because they are not designed for that purpose
Parking brakes are only used on two of the wheels and are applied with far less force than the service brakes

5. Introduction Click on image above to play video
Automotive Brake Systems, Sixth Edition
Chapter 9, Parking Brakes
Introduction
Video providing a brief overview of parking brake function and operation.
Click on image above to play video

6. Parking Brake Operation
Automotive Brake Systems, Sixth Edition
Chapter 9, Parking Brakes
Parking Brake Operation
Parking brakes are not part of the hydraulic system
Operated mechanically (typically using levers and cables) to apply the rear brakes
Some vehicles use a drum brake attached to the driveshaft for the parking brake
Most parking brakes use the same friction material as the service brakes
Those using their own linings are called independent parking brakes
Parking brakes may be applied using a hand lever, foot pedal, or electronically

7. Parking Brake Operation
Automotive Brake Systems, Sixth Edition
Chapter 9, Parking Brakes
Parking Brake Operation
An illustration of a typical hand lever parking brake control. (Image – Classroom Manual Pg. 212)

8. Parking Brake Operation
Automotive Brake Systems, Sixth Edition
Chapter 9, Parking Brakes
Parking Brake Operation
An illustration of a typical foot pedal parking brake control. (Image – Classroom Manual Pg. 212)

9. Parking Brake Operation
Automotive Brake Systems, Sixth Edition
Chapter 9, Parking Brakes
Parking Brake Operation
A typical electronic parking brake control switch and an externally mounted electronic parking brake actuator.
(Images – Classroom Manual Pg. 213)

10. Name three ways that parking brakes can be controlled.
Automotive Brake Systems, Sixth Edition
Chapter 9, Parking Brakes
Answer: Hand Lever, Foot Pedal, Electronically
Name three ways that parking brakes can be controlled.

11. Parking Brake Controls – Levers and Pedals
Automotive Engine Performance, Sixth Edition
Chapter 9, Parking Brakes
Parking Brake Controls – Levers and Pedals
Parking Brake Control – the component the driver uses to set and release the parking brake
Lever
Typically installed between the front seats
Some are installed under the dash
Example of an under-dash hand operated parking brake control as used on many older cars and trucks. (Image – Classroom Manual Pg. 213)

12. Parking Brake Controls – Levers and Pedals
Automotive Engine Performance, Sixth Edition
Chapter 9, Parking Brakes
Parking Brake Controls – Levers and Pedals
Pedal
Mounted under the dash on the far left
Used more often on heavier vehicles to allow greater force
May have a release lever, be push to release, or have an automatic release
Example of an under-dash pedal operated parking brake control. (Image – Classroom Manual Pg. 215)

13. Parking Brake Controls – Levers and Pedals
Automotive Engine Performance, Sixth Edition
Chapter 9, Parking Brakes
Parking Brake Controls – Levers and Pedals
Parking Brake Standards
Set by FMVSS 105
Parking brake must hold vehicle stationary for five minutes on a 30% grade in both directions
Application force must not exceed 125 lbs. for foot operated brakes and 90 lbs. for hand operated brakes
Illustration of parking brake safety standards. (Image – Classroom Manual Pg. 215)

14. Parking Brake Controls – Levers and Pedals
Automotive Engine Performance, Sixth Edition
Chapter 9, Parking Brakes
Parking Brake Controls – Levers and Pedals
Automatic Parking Brake Release
Typically release when transmission is placed in gear
Older systems used vacuum diaphragms
Newer systems use computer control of electronic parking brake actuator(s)
Animation shows basic components and operation of a vacuum operated automatic parking brake release.
Click on image above
to view animation

15. Automotive Engine Performance, Sixth Edition
Chapter 9, Parking Brakes
Answer: 30; 5
The parking brake must be capable of holding the vehicle on a 30 % grade for at least _______ minutes.

16. Automotive Brake Systems, Sixth Edition
Chapter 9, Parking Brakes
Warning Lamps
Red Brake warning light standard since 1967 is also used to indicate parking brake is applied
Should turn off only once completely released
Light may ‘prove out’ when ignition is first turned on
Image shows a typical parking brake warning light switch being tested. (Image – Shop Manual Pg. 438)

17. Designed to transmit force equally to both brake assemblies
Automotive Brake Systems, Sixth Edition
Chapter 9, Parking Brakes
Parking Brake Linkage
Designed to transmit force equally to both brake assemblies
Front cable connects control to equalizer
Rear cable(s) connect equalizer to rear brakes
Images of typical equalizer assemblies. (Images – Classroom Manual Pg. 216)

18. Connectors may be used between cables
Automotive Brake Systems, Sixth Edition
Chapter 9, Parking Brakes
Parking Brake Linkage
Connectors may be used between cables
Retainer clips and brackets are used to support cables and prevent excessive flexing
Images of parking brake cable connectors, retainers, and clips. (Images – Classroom Manual Pg. 217)

19. Parking Brake Linkage Automotive Brake Systems, Sixth Edition
Chapter 9, Parking Brakes
Parking Brake Linkage
Typical parking brake cable construction. (Image – Classroom Manual Pg. 218)

20. Some parking brake cables use a solid rod in place of a flexible cable
Automotive Brake Systems, Sixth Edition
Chapter 9, Parking Brakes
Parking Brake Linkage
Some parking brake cables use a solid rod in place of a flexible cable
Commonly used in place of a front cable when the equalizer is located within a foot or so of the hand control
Intermediate levers are used in some parking brake systems to provide greater mechanical advantage and higher application force to the brakes

21. Automotive Brake Systems, Sixth Edition
Chapter 9, Parking Brakes
Answer: Control; Equalizer
The front parking brake cable typically connects the ____________ to the ____________.

22. Rear Drum Parking Brakes
Automotive Brake Systems, Sixth Edition
Chapter 9, Parking Brakes
Rear Drum Parking Brakes
Rear cable enters through the backing plate
Cable pulls on a lever to apply the rear brake shoes
Service brake adjustment should be checked before adjusting the parking brake system
Illustrations of rear drum parking brake components. (Images – Classroom Manual Pg. 218 & 220)

23. Rear Drum Parking Brakes
Automotive Brake Systems, Sixth Edition
Chapter 9, Parking Brakes
Rear Drum Parking Brakes
Illustration of rear drum parking brake components and operation. (Image – Classroom Manual Pg. 220)

24. Electrical Parking Brake Systems
Automotive Brake Systems, Sixth Edition
Chapter 9, Parking Brakes
Electrical Parking Brake Systems
Use an electric actuator to physically apply the parking brake
May be connected to the rear cable(s) or integral to the rear calipers
Will hold even if electrical power is lost
Images of external and integral electric parking brake actuators. (Images – Classroom Manual Pg. 221)

25. Rear Disc Parking Brakes
Automotive Brake Systems, Sixth Edition
Chapter 9, Parking Brakes
Rear Disc Parking Brakes
Vehicles with rear disc brakes may use one of two parking brake systems:
Auxiliary Drum Parking Brakes
Use a small drum brake within the hat of each rotor exclusively for parking brake use
Also called a ‘Drum in Hat’ parking brake
Does not use self-adjusters
Caliper-Actuated Parking Brakes
Use brake calipers with a special mechanism built in to allow rear brake pads to be mechanically applied
May be of the screw and nut, ball and ramp, or cam and lever type

26. Rear Disc Parking Brakes
Automotive Brake Systems, Sixth Edition
Chapter 9, Parking Brakes
Rear Disc Parking Brakes
Typical auxiliary drum parking brake. (Image – Classroom Manual Pg. 222)

27. Rear Disc Parking Brakes
Automotive Brake Systems, Sixth Edition
Chapter 9, Parking Brakes
Rear Disc Parking Brakes
Typical GM style screw and nut rear caliper. (Image – Classroom Manual Pg. 223)

28. Rear Disc Parking Brakes
Automotive Brake Systems, Sixth Edition
Chapter 9, Parking Brakes
Rear Disc Parking Brakes
Typical Ford style ball and ramp rear caliper. (Image – Classroom Manual Pg. 224)

29. Rear Disc Parking Brakes
Automotive Brake Systems, Sixth Edition
Chapter 9, Parking Brakes
Rear Disc Parking Brakes
Typical Honda style cam and lever rear caliper. (Image – Shop Manual Pg. 425)

30. Automotive Brake Systems, Sixth Edition
Chapter 9, Parking Brakes
Answer: False.
True or False? An electronic parking brake will release if battery power is lost.

31. Name three types of caliper-actuated parking brakes.
Automotive Brake Systems, Sixth Edition
Chapter 9, Parking Brakes
Answer: Screw and nut; Ball and Ramp; Cam and Lever. (Electronic would also be an acceptable answer).
Name three types of caliper-actuated parking brakes.

32. Parking Brake Diagnosis and Service
Automotive Brake Systems, Sixth Edition
Chapter 9, Parking Brakes
Parking Brake Diagnosis and Service
Check parking brake control travel
Excessive travel could indicate excessive clearance, a stretched cable, or an adjustment issue
Always check service brake adjustment first
Example of parking brake control travel specifications. (Image – Shop Manual Pg. 427)

33. Parking Brake Diagnosis and Service
Automotive Brake Systems, Sixth Edition
Chapter 9, Parking Brakes
Parking Brake Diagnosis and Service
Inspect linkage and cables for damage
Performance Test
Verify parking brake will hold vehicle at 30% grade in both directions in neutral
Example of typical parking brake linkage inspection points. (Image – Shop Manual Pg. 427)

34. Parking Brake Diagnosis and Service
Automotive Brake Systems, Sixth Edition
Chapter 9, Parking Brakes
Parking Brake Diagnosis and Service
Explain typical parking brake adjustment points and procedures. (Images – Shop Manual Pg. 428 and Pg. 429)

35. Parking Brake Diagnosis and Service
Automotive Brake Systems, Sixth Edition
Chapter 9, Parking Brakes
Parking Brake Diagnosis and Service
Example of auxiliary drum parking brake adjustment. (Image – Shop Manual Pg. 433)
Auxiliary Drum Parking Brake Shoe Adjustment
Adjuster may be accessed through backing plate or through rotor depending on the vehicle
There is no self adjuster pawl or lever to hold out of the way

36. Parking Brake Diagnosis and Service
Automotive Brake Systems, Sixth Edition
Chapter 9, Parking Brakes
Parking Brake Diagnosis and Service
Electric Parking Brake Systems
Systems with external actuators and cables may still have adjustment available
Some systems may require a compatible scan tool to keep parking brake released or retract caliper piston for brake pad service

37. Automotive Brake Systems, Sixth Edition
Chapter 9, Parking Brakes
Answer: Service Brakes.
On a drum brake parking brake system, which should be adjusted first: Service Brakes or Parking Brakes?