Question 1

A hubless brake drum cannot be machined because it cannot be held in a lathe.

Accepted Answer

A) True 
 B)False  False

Question 2

The major reason for brake pedal pulsation during braking is due to excessive rotor thickness variation.

Accepted Answer

A) True 
 B)False  True

Question 3

What is the reading on this micrometer?

Accepted Answer

0.224 "

Question 4

Which is NOT a type of brake drum construction?

Accepted Answer

A) Centrifugally cast 
B) Bimetallic 
C) Solid composite 
D) Composite 
A) Centrifugally cast 
B) Bimetallic 
C) Solid composite 
D) Composite

Question 5

Two technicians are discussing disc brake rotor service. Technician A says that the inner races (bearing cups) should be removed from the rotor before it is mounted on the lathe. Technician B says that a non-directional finish on the rotor surfaces can be obtained by using sandpaper. Which technician is correct?

Accepted Answer

A) Technician A only 
B) Technician B only 
C) Both technicians A and B 
D) Neither technician A nor B 
A) Technician A only 
B) Technician B only 
C) Both technicians A and B 
D) Neither technician A nor B

Question 6

What is the reading on this micrometer?

Accepted Answer

The answer of What is the reading on this micrometer?
...

Question 7

Typical maximum rotor thickness variation (parallelism) specifications are ________.

Accepted Answer

A) 0.030 to 0.050 in. (0.8 to 1.3 mm) 
B) 0.0003 to 0.0005 in. (0.008 to 0.013 mm) 
C) 0.003 to 0.005 in. (0.08 to 0.13 mm) 
D) 0.300 to 0.500 in. (8.0 to 13 mm) 
A) 0.030 to 0.050 in. (0.8 to 1.3 mm) 
B) 0.0003 to 0.0005 in. (0.008 to 0.013 mm) 
C) 0.003 to 0.005 in. (0.08 to 0.13 mm) 
D) 0.300 to 0.500 in. (8.0 to 13 mm)

Question 8

Which one is not a form of drum distortion?

Accepted Answer

A) Out-of-round 
B) Lack of parallelism 
C) Bellmouth 
D) Eccentric 
A) Out-of-round 
B) Lack of parallelism 
C) Bellmouth 
D) Eccentric

Question 9

What is the reading on this micrometer?

Accepted Answer

The answer of What is the reading on this micrometer?
...

Question 10

Technician A says that hard spots in a brake drum should be removed using a carbide-tip machining tool. Technician B says that the drum should be replaced if hard spots are discovered. Which technician is correct?

Accepted Answer

A) Technician A only 
B) Technician B only 
C) Both technicians A and B 
D) Neither technician A nor B 
A) Technician A only 
B) Technician B only 
C) Both technicians A and B 
D) Neither technician A nor B

Question 11

A disc brake rotor is being installed on a lathe for machining. During the setup a scratch test is performed. The scratch extended all the way around the rotor. Technician A says that the rotor should be loosened, rotated 180 degrees, and retightened. Technician B says that the rotor is not warped. Which technician is correct?

Accepted Answer

A) Technician A only 
B) Technician B only 
C) Both technicians A and B 
D) Neither technician A nor B 
A) Technician A only 
B) Technician B only 
C) Both technicians A and B 
D) Neither technician A nor B

Question 12

The chamfer on the inside edge of a brake drum usually indicates ________.

Accepted Answer

A) Machine to diameter 
B) Maximum allowable inside diameter 
C) Aluminum drum with cast iron inset 
D) Bi-metallic drums (1/2 cast iron and 1/2 steel) 
A) Machine to diameter 
B) Maximum allowable inside diameter 
C) Aluminum drum with cast iron inset 
D) Bi-metallic drums (1/2 cast iron and 1/2 steel)

Question 13

The lower the Ra of a rotor, the ________ the surface.

Accepted Answer

A) Higher 
B) Lower 
C) Smoother 
D) Rougher 
A) Higher 
B) Lower 
C) Smoother 
D) Rougher

Question 14

Technician A says that aluminum brake drums use cast iron friction surfaces. Technician B says that up to 0.030 in. (0.8 mm) should be left after machining a drum to allow for wear. Which technician is correct?

Accepted Answer

A) Technician A only 
B) Technician B only 
C) Both technicians A and B 
D) Neither technician A nor B 
A) Technician A only 
B) Technician B only 
C) Both technicians A and B 
D) Neither technician A nor B

Question 15

Two technicians are discussing the machining of brake drums. Technician A says that most brake drums cannot be machined more than 0.060 in. oversize. Technician B says that brake drums on a common axle should be machined to within 0.010 in. of each other. Which technician is correct?

Accepted Answer

A) Technician A only 
B) Technician B only 
C) Both technicians A and B 
D) Neither technician A nor B 
A) Technician A only 
B) Technician B only 
C) Both technicians A and B 
D) Neither technician A nor B

Question 16

Technician A says heat checking can be caused by numerous panic stops in rapid succession. Technician B says it can be caused by "riding" the brake pedal. Which technician is correct?

Accepted Answer

A) Technician A only 
B) Technician B only 
C) Both technicians A and B 
D) Neither technician A nor B 
A) Technician A only 
B) Technician B only 
C) Both technicians A and B 
D) Neither technician A nor B

Question 17

Two technicians are discussing hard spots in brake drums. Technician A says the drum should be replaced. Technician B says the hard spots are caused by using riveted rather than bonded brake shoes. Which technician is correct?

Accepted Answer

A) Technician A only 
B) Technician B only 
C) Both technicians A and B 
D) Neither technician A nor B 
A) Technician A only 
B) Technician B only 
C) Both technicians A and B 
D) Neither technician A nor B

Question 18

Technician A says there are no brake lathes that can machine rotors on the vehicle. Technician B says drums may be removed from the vehicle to be machined. Which technician is correct?

Accepted Answer

A) Technician A only 
B) Technician B only 
C) Both technicians A and B 
D) Neither technician A nor B 
A) Technician A only 
B) Technician B only 
C) Both technicians A and B 
D) Neither technician A nor B

Question 19

Most manufacturers specify that the friction surfaces of a rotor must be parallel to within ________.

Accepted Answer

A) 0.005 inch (0.127 mm) 
B) 0.0001 inch (0.0025 mm) 
C) 0.001 inch (0.0254 mm) 
D) 0.0005 inch (0.013 mm) 
A) 0.005 inch (0.127 mm) 
B) 0.0001 inch (0.0025 mm) 
C) 0.001 inch (0.0254 mm) 
D) 0.0005 inch (0.013 mm)

Question 20

Technician A says anti-vibration devices only need to be used when resurfacing drums. Technician B says composite brake rotors require special adapters when mounted on a bench lathe for resurfacing. Which technician is correct?

Accepted Answer

A) Technician A only 
B) Technician B only 
C) Both technicians A and B 
D) Neither technician A nor B 
A) Technician A only 
B) Technician B only 
C) Both technicians A and B 
D) Neither technician A nor B

Exam 104: Machining Brake Drums and Rotors

A hubless brake drum cannot be machined because it cannot be held in a lathe.

The major reason for brake pedal pulsation during braking is due to excessive rotor thickness variation.

What is the reading on this micrometer?

Which is NOT a type of brake drum construction?

What is the reading on this micrometer?

Typical maximum rotor thickness variation (parallelism) specifications are ________.

Which one is not a form of drum distortion?

What is the reading on this micrometer?

Technician A says that hard spots in a brake drum should be removed using a carbide-tip machining tool. Technician B says that the drum should be replaced if hard spots are discovered. Which technician is correct?

The chamfer on the inside edge of a brake drum usually indicates ________.

The lower the Ra of a rotor, the ________ the surface.

Technician A says that aluminum brake drums use cast iron friction surfaces. Technician B says that up to 0.030 in. (0.8 mm) should be left after machining a drum to allow for wear. Which technician is correct?

Two technicians are discussing the machining of brake drums. Technician A says that most brake drums cannot be machined more than 0.060 in. oversize. Technician B says that brake drums on a common axle should be machined to within 0.010 in. of each other. Which technician is correct?

Technician A says heat checking can be caused by numerous panic stops in rapid succession. Technician B says it can be caused by "riding" the brake pedal. Which technician is correct?

Two technicians are discussing hard spots in brake drums. Technician A says the drum should be replaced. Technician B says the hard spots are caused by using riveted rather than bonded brake shoes. Which technician is correct?

Technician A says there are no brake lathes that can machine rotors on the vehicle. Technician B says drums may be removed from the vehicle to be machined. Which technician is correct?

Most manufacturers specify that the friction surfaces of a rotor must be parallel to within ________.

Technician A says anti-vibration devices only need to be used when resurfacing drums. Technician B says composite brake rotors require special adapters when mounted on a bench lathe for resurfacing. Which technician is correct?

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