Deck 51: Drum Brakes

Question 1

Small lightweight cars often use duo-servo drum brake designs to reduce brake lockup.

Answer 1

False

Question 2

A self-adjuster screw mechanism (star wheel)  can be positioned on either the left or the right side of the vehicle.

Answer 2

False

Question 3

In normal forward braking, the friction developed by the primary lining is greater than the secondary lining.

Answer 3

False

Question 4

The inability of drums to dissipate as much heat as disc brakes is one of the main reasons discs have replaced drums at the front of all late model cars and light trucks

Question 5

Hydraulic system parts should never have contact with oil or grease.

Question 6

On duo-servo designs, the rear shoe is the primary, and the front shoe is the secondary.

Question 7

Both non-servo drum brake leading and training shoes are self-energizing as the brakes are applied and the vehicle is moving forward.

Question 8

Parking brake mechanisms provide a hydraulic force to apply the brake shoes and keep the vehicle stationary.

Question 9

Duo-servo drum brake systems use an adjusting screw assembly and spring to connect the lower ends of the shoes.

Question 10

Heat checks are visible only after the drum has been machined.

Question 11

The self-adjusters (star wheels)for the left side and the right side are interchangeable.

Question 12

Riveted linings allow for better heat transfer than bonded linings.

Question 13

Regardless of the method of attachment, brake shoes are usually held in a position by spring tension.

Question 14

Stepping on the brake pedal while a brake drum is off can cause the pistons in the wheel cylinder to overextend or pop apart.

Question 15

A floating drum is mounted on the hub and wheel bearing assembly.

Question 16

Some anchor pins are adjustable.

Question 17

Drum brake hardware includes return springs, holddown parts, and linkages.

Question 18

Drum brakes are still used on the front wheels of many late model cars and light trucks.

Question 19

On most cars, the push nuts that hold the drum onto the studs of a floating drum do not need to be reinstalled after service.

Question 20

Before test driving any car, first check the fluid level in the master cylinder and depress the brake pedal to be sure there is adequate pedal reserve.

Question 21

In the unapplied position, drum brake shoes are held against the anchor pin by the ______.

A)holddown springs
B)star wheel adjuster
C)shoe holddown
D)return springs

Question 22

On most vehicles, the automatic adjuster system ______.

A)is installed on the primary shoe
B)is installed on the secondary shoe
C)operates when the brakes are applied as the vehicle moves forward
D)operates when the brakes are not applied

Question 23

A buildup of brake dust and dirt between the lining and the drum is the most common cause of a ______.

A)barrel-shaped drum
B)taper-shaped drum
C)scored drum surface
D)threaded drum surface

Question 24

In a typical drum brake, which component provides a foundation for the brake shoes and associated hardware?

A)backing plate
B)drum
C)lining
D)wheel cylinder

Question 25

Technician A tests brake drums for out-of-round using a dial indicator. Technician B measures the drum diameter in several places to check for out-of-round. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 26

Technician A says the discard dimension of a brake drum is the drum's allowable machining dimension. Technician B says a drum may be machined and used if within 10 percent of the discard dimension. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 27

The function of the wheel cylinder is to ______.

A)convert hydraulic pressure to a mechanical force at the drum brakes
B)maintain correct shoe position and clearance
C)prohibit the shoe from following the movement of the rotating drum
D)provide the rubbing surface area for the linings

Question 28

Technician A says brake linings are riveted to the brake shoes. Technician B says brake linings are bonded to the brake shoes. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 29

After resurfacing a brake drum, Technician A cleans it using hot soapy water and a lint-free cloth until it is thoroughly dry. Technician B cleans the drum using a lint-free cloth dipped in a special brake cleaning solution. Who is correct

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 30

Brake linings should be replaced when linings are ______.

A)worn to within 1/32 inch (.794 mm)of a rivet head
B)contaminated with oil or grease
C)contaminated with brake fluid
D)All the answers are correct.

Question 31

Technician A says an out-of-round drum can cause a pulsating brake pedal. Technician B says an out-of-round drum can cause the brakes to grab. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 32

Technician A says some drums are made entirely of cast iron. Technician B says some drums are made entirely of aluminum. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 33

Rear wheel brake drum removal is being discussed. Technician A says that on some FWD vehicles, the rear bearings must be disassembled to remove the drum. Technician B says that on some FWD vehicles, the drums are held in place by wheel lugs. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 34

Servicing a brake drum with hard spots that are causing chatter and brake pull is being discussed. Technician A says he can grind off the hard spots. Technician B says the drum must be replaced. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 35

Duo-servo drum brakes are also known as __________.

A)leading-trailing brakes
B)self-energizing brakes
C)non-servo brakes
D)None of the answers is correct.

Question 36

Technician A says on most vehicles, the self-adjuster system is installed on the primary shoe. Technician B says the system will self-adjust when the brakes are applied and the vehicle is backing up. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 37

Technician A says brake shoe return springs can be separately hooked into a link or a guide. Technician B says the springs may be strung between the shoes. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 38

A drum with a taper or out-of-roundness exceeding 0.006 inch (0.152 mm)is considered ______.

A)acceptable
B)acceptable if polished with emery cloth
C)unacceptable and must be rebalanced
D)unacceptable and must be turned or replaced

Question 39

The parking brake cables should be adjusted before performing regular wheel brake service.

Question 40

Duo-servo drum brake systems are being discussed. Technician A says the primary shoe lining is often thicker than the secondary shoe lining. Technician B says the primary shoe typically has more lining surface area than the secondary shoe. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 41

A car with a broken timing belt is towed to your shop. The tow truck operator set the parking brake. The vehicle has an automatic vacuum parking brake release. Because the engine can't be started, the brakes won't release. How do you get the car into the shop?

A)Back off the parking brake cable at the equalizer bar
B)Back off the star wheel adjusters
C)Raise the rear wheels with a floor jack and push the vehicle on the jack
D)Pull the manual release lever on the side of the parking brake pedal assembly

Question 42

A clicking noise heard when the brakes are applied could be caused by ______.

A)frozen star wheel
B)play in the attachment of the pad or shoe
C)brake fluid or grease on the linings
D)scored drums

Question 43

Technician A says the anchor pin acts as a brake shoe stop. Technician B says the return springs on a duo-servo brake are hooked over the anchor pin. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 44

What tool is used to adjust the brake shoes before the drum is installed?

A)drum micrometer
B)dial indicator
C)dial caliper
D)shoe set gauge

Question 45

During a brake inspection, the technician discovers that the right rear brake shoes are soaked with a liquid. Technician A says the wheel axle seal is leaking. Technician B says the wheel cylinder is leaking. Who is correc t?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 46

Before removing the drum on a nondriven wheel, you should remove _____________.

A)the dust cap
B)the cotter pin and castellated nut
C)the thrust washer and outer wheel bearing
D)All the answers are correct.

Question 47

Wheel cylinders should be rebuilt or replaced if _____.

A)substantial amounts of brake fluid are found inside the boots
B)wheel cylinder pistons are binding in their bores
C)the brake has been contaminated with petroleum-based lubricants
D)All the answers are correct.

Question 48

A customer complains that the car pulls to the left during hard braking. An inspection shows that the front pads and rear shoes are worn. After resurfacing the rotors and drums and replacing the pads and shoes, a road test reveals that the car still pulls to the left during hard braking. Technician A says the wheel alignment should be checked. Technician B says the tires could be the problem and should be swapped left to right to check whether the direction of the pull changes. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 49

Technician A says the leading shoe in a non-servo brake does most of the work when the brakes are applied while in reverse. Technician B says the trailing shoe does most of the work when the brake are applied while moving forward. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 50

The left rear brake drum is scored, but the right rear drum looks as good as new. Technician A says the left-side drum should be resurfaced and the right-side drum should be reinstalled without resurfacing. Technician B says both sides should be remachined to a similar diameter. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 51

Technician A says self-adjustment occurs on most duo-servo brakes whenever the foot brake is applied while backing up. Technician B says self-adjustment occurs on a non-servo brake whenever the foot brake is applied when driving forward. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 52

What must be done first to remove a brake drum that is ridged and cannot be pulled past the edge of the shoes?

A)loosen the parking brake cables
B)manually retract the star wheel adjuster
C)pry the drum off with a large screwdriver
D)remove the drum with a slide hammer

Question 53

A grinding noise when the brakes are applied could be caused by ______.

A)weak return springs
B)weak holddown springs
C)worn shoes
D)All the answers are correct.

Question 54

The last two letters printed on the edge of the shoe lining indicate ____.

A)shoe position (right-primary etc.)
B)heat resistance
C)nominal drum diameter
D)COF (coefficient of friction)

Question 55

The effort of the parking brake pedal assembly or handgrip is multiplied and passed onto the rear cables by the ____________________ lever.

Question 56

Technician A removes brake dust from the brake assembly with compressed air. Technician B uses an OSHA-approved brake washer to clean drum brake assemblies. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 57

Non-servo type brakes are normally found on __________.

A)small, lightweight passenger cars
B)large, full-size domestic cars
C)pickup trucks and SUVs
D)vehicles that have power brakes

Question 58

A brake inspection reveals a leaking wheel cylinder that has soaked the brake shoes with brake fluid. The shoes are virtually new, and the drums are in excellent condition. Technician A says to clean the brake assembly with an aqueous brake cleaner, then thoroughly clean the shoes with a brake cleaning solvent. Technician B says thoroughly clean the brake assembly, then install new brake shoes. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 59

Technician A says on a duo-servo brake the front shoe is called the primary shoe and the rear is the secondary shoe. Technician B says on a non-servo brake, the front shoe is called the leading shoe and the rear is the trailing shoe.

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 60

Technician A replaces self-adjusters with worn teeth. Technician B swaps the left and right side star wheel adjuster positions so that  the adjuster pawl gets an unworn surface against which to ratchet. Who is correct?

A)A only
B)B only
C)both A and B
D)neither A nor B

Question 61

Explain the operation of an integral drum brake parking brake.

Question 62

Shoe ____________________ springs and shoe holddown parts maintain the correct shoe position and clearance.

Question 63

On duo-servo drum systems, the rear brake shoe is often called the ____________________ shoe.

Question 64

The brake shoe lining provides ____________________ against the drum to stop the car.

Question 65

Another term for nonservo-type brakes is ____________________.

Question 66

Identify six common brake problems.

Question 67

Brake shoes containing significant amounts of ____________________ dust can be a potential health hazard.

Question 68

Some vehicles use a(n)____________________ motor to release the parking brake when the engine is running and the transmission is in a forward driving gear.

Question 69

Brake drums can be refinished by either turning or grinding on a ____________________.

Question 70

Identify the two drum brake system designs.

Question 71

List at least five types of wear or distortion to look for when inspecting brake drums.

Question 72

The brake's ____________________ pin acts as a brake shoe stop and prohibits the brake shoe from its tendency to follow the movement of the rotating drum.

Question 73

Explain how drum brakes create a self-multiplying (self-energizing)brake force.

Question 74

On duo-servo drum systems, the forward brake shoe is often called the ____________________ shoe.

Question 75

The lever that moves the star wheel on the self-adjuster is often called a(n)____________________.

Question 76

When must a wheel cylinder be replaced?

Question 77

What three checks should be made before conducting a road test for a brake problem?

Question 78

On a duo-servo brake, the primary shoe is connected to the secondary shoe by the ____________________.

Question 79

To dissipate the heat from braking, the brake drum acts as a heat ____________________.

Question 80

After machining, the brake drum must be at least ____________________ inch smaller than the discard diameter stamped or cast into the drum.