Chapter 8 Flashcards
1.List the components of a typical drum brake assembly.
backing plate, brake drum, shoe, wheel cylinder, and various springs and pins.
2.Describe the function of a wheel cylinder.
Wheel cylinders convert hydraulic pressure from the master cylinder to mechanical force that applies the brake shoes.
3.Describe brake gas fade.
Gas fade is a condition that occurs under hard braking when hot gases and dust particles are trapped between the brake linings and the drum or rotor and build up pressure that acts against brake force
4.What are the major advantages to using drum brakes?
The major drum brake advantages are self-energizing and servo action, lack of noise, and efficient parking brake operation without complicated linkage.
5.Since duo-servo brakes supply more braking force than leading-trailing drum brakes, why would engineers use the leading-trailing design?
FWD automobiles generate up to 80 percent of their braking force on the front wheels. Overly powerful duo-servo brakes at the rear could easily cause the rear wheels to lock as weight shifts forward and the rear end becomes very light during braking
6.What determines the braking surface area of a drum brake?
The braking surface area of a drum is determined by the diameter and the depth (width) of the drum.
7.What is the function of a self-adjuster?
Brake adjustment compensates for lining wear and maintains correct clearance between
brake linings and the drum.
8.What is a self-energizing brake?
To add its own mechanical leverage to hydraulic force to help apply the brakes
9.What is the difference between the braking action of leading-trailing and duo-servo brakes?
A duo-servo brake is distinguished from a leading-trailing brake by a single anchor post at the top of the backing plate.
10.How are the brake shoes returned to their released position when the brake pedal is released?
Strong return springs retract the shoes when the brakes are released and hold them
against their anchors and the wheel cylinder pushrod.
. _______________ are the components that mount the friction material or linings that contact the drums.
brake shoes
The hydraulic and friction components are attached to the______________
Backing plate
_______________ operation is the action of a drum brake shoe when drum rotation increases the application force of the shoe by wedging it tightly against the drum.
Self engergizing
The _______________is usually part of the parking brake strut that is mounted between the two shoes of leading-trailing brakes.
Star wheel
A duo-servo brake is distinguished from a leading-trailing brake by a single anchor post at the _______________ of the backing plate.
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