E - Parking Brake System Fundamentals and Service Flashcards
Explain the primary function of a parking brake.
The parking brake is designed to hold the vehicle stationary when left unattended.
Name the brake system which the mechanical linkage wheel type uses as a key part of the parking brake system.
The vehicle service brake system is a necessary part of the mechanical linkage wheel type park brake.
True or False: The equalizer bracket is used between the hand brake cable and the cables leading to the rear wheels.
True.
Explain how you would determine what type of fluid would be appropriate to use in the hydraulically operated parking brake system.
Service brakes use a recommended brake fluid. Hydraulic parking brake systems use a specific type of hydraulic fluid. A vehicle service manual would identify the type.
The park brake cylinder and wedge assembly used in some parking brakes contains a power spring. Explain the precautions you should observe when working around this type of cylinder.
Follow the manufacturer’s recommendations for handling, removal and installation. Cage the spring before disassembly as personal injury dangers exist.
True or False: Park brakes may use a cable as an actuating device. The cable length is adjusted after all other adjustments.
True.
A driveshaft type of parking brake may be rendered ineffective if:
The driveshaft or a universal joint is broken. The driveshaft is disconnected or removed. Or the one rear wheel is jacked up off the ground.
After adjusting a parking brake, what must you do before allowing the vehicle back on the road?
Test the operation of the brake and make sure it is definitely released when the park brake lever, pedal or switch is in the released position.
Explain the precautions required when working with the parking brake actuator used in some trucks.
Follow the manufacturer’s recommendations for handling, removal and installation. Do not disassemble the actuator as it is a sealed unit. Personal injury dangers exist.
True or False: The electric/hydraulic parking brake uses an electronic parking brake control module.
True.
Explain what checks you would perform before adjusting anything on a hydraulically operated park brake or an electric/hydraulic park brake
Check hydraulic fluid reservoir level. Check for signs of leakage anywhere in the hydraulic portion of the park brake system and repair the damage. If the pump is belt driven, check the belt tension. Check electric drive pumps for operation.
True or False: Hydraulic park brakes and electric/hydraulic park brakes are spring applied and fluid pressure released.
True.
Explain the adjustment procedure for an external band driveshaft type park brake.
Determine lining-to-drum specifications and adjustment procedure from service manual. Set aside, upper and lower lining-to-drum clearances and tighten adjusting screws. Set cable length. Install pin and new cotter pin. Apply and release several times and re-check measurements. Confirm brakes are fully released when cab lever or pedal is fully released.
The hydraulically operated or the electric/hydraulic park brake systems use very high system pressures. Before you remove a hydraulic line, explain how you could release the pressure to prevent personal injury.
Follow the manufacturer’s warnings and instructions. With the engine off and the ignition key off, apply and release the parking brake several times. Do not remove a line without first cracking the fitting loose and allowing any remaining pressure to bleed off. Wear eye protection.
State two precautions to observe when working on or near the electronic components in the park brake system.
Do not short or ground any terminals (unless it is a test outlined in the service manual).
Do not disconnect an electronic component when the system is powered (generally when the ignition key is on).
