Assignment 5 - Drum Brake Service
Assign_5_drumbrakes Assignment 5 - Drum Brake Service
Name(s) ______BE SURE TO SAVE THIS FILE before, during and after completing your work. (Hint – if you write your name, then save and close this, your name will still appear when you re-open the file)
Refer to this picture to answer questions 1 through 7. You can find answers using the index of Automotive Chassis Systems by James Halderman
1) What is a simple way to test that the Power Booster is operating? (Vacuum booster operation check)
2) What is the name of the hydraulic unit that activates the front disc brakes?
3) What is the name of the hydraulic unit that activates the rear drum brakes?
4) What does the metering valve do?
5) When would the brake warning light switch turn on the brake warning lamp?
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6) What does the proportioning valve do?
7) Why does the master cylinder use a primary and a secondary piston? (Why is this safer than just using one piston?)
Questions #8 – 24 can be answered after studying the information in Chapter 10 of Automotive Chassis Systems by James Halderman
8) What are the advantages of Drum Brakes over Disc Brakes?
9) What are disadvantages of using Drum Brakes?
10) What is the function of the Backing Plate?
11) What is the function of the Shoe Anchor?
12) What kind of grease should you use on Shoe Support Pads?
13) What is the function of the Wheel Cylinder?
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14) In a Dual Servo drum brake design there is a primary and secondary brake shoe. Describe the difference between the primary and secondary brake shoe?
15) What are advantages to using Riveted brake linings?
16) What are dis-advantages to using Riveted brake linings?
17) What is significant about brake lining edge codes?
18) What is the difference between a brake return spring and a hold down spring?
19) What is the difference between a leading brake shoe and trailing brake shoe?
20) What is the difference between a Leading-Trailing brake design (non-servo) and the Dual Servo brake design?
21) Front wheel drive cars are most likely to use ___ Dual Servo drum brakes ___ Double Trailing drum brakes ___ Leading –Trailing drum brakes
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22) In a dual servo drum brake design, which brake shoe provides the most braking power? (select the 3 correct answers from this list and assume the vehicle is going forward) ___ The primary brake shoe ___ The secondary brake shoe ___ The shorter brake shoe ___ The longer brake shoe ___ The shoe facing the front of the vehicle ___ The shoe facing the rear of the vehicle
23) Self adjusters have left and right handed threads. If they are not installed on the correct side of the vehicle they will work backwards. Why might this cause the brakes to grab?
24) Explain – in detail – how one type of drum brake adjuster operates.
Questions #25 – 33 can be answered after studying the information in Chapter 10 of Automotive Chassis Systems by James Halderman
25) Other than cleaning the brake assembly, why should you use brake solvent or a water based | brake washer to wet down the drum brake assembly before replacing brake shoes?
26) When inspecting backing plates there are six raised contact surfaces that must not be worn. These are called shoe support pads or ledges. What causes them to wear?
27) If shoe support pads have grooves worn deeper than 1/16” what should you do?
28) Lubricating the shoe support pads is important when replacing brake shoes. What should you use to lubricate the support pads on the backing plate?
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29) What is generally the minimum allowable lining thickness for a drum brake shoe?
30) Why might you recommend new drum brake springs even if the old ones look fine?
31) Why might you recommend that wheel cylinders be replaced EVERY time you replace the drum brake shoes?
32) What should you do to the star wheel adjuster when replacing brake shoes? (check all that apply) ___ Completely disassemble and clean – especially the adjusting threads ___ Lubricate all rotating parts (including threads) with wheel bearing grease ___ Lubricate all rotating parts (including threads) with synthetic disc brake grease ___ Ensure the self adjuster is installed on the proper side of the vehicle 33) Why is it a good idea to place masking tape on your new brake shoes before you begin to install them on the vehicle?
34) Some brake parts must not be switched from the left side to the right side of the vehicle. Also there are many variations on how brake springs, clips, and self adjusters are properly assembled. What does your instructor recommend you do to prevent switching parts from one side to the other and to allow you to have a reference for the proper assembly of all springs, clips and adjusters? (ask in class for this answer!)
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Match these terms to this picture (This is a Dual Servo drum brake design)
____ - primary brake shoe
____ - Wheel Cylinder
____ - Hold down spring
____ - Anchor
____ - Self Adjuster
____ - Return Spring
____ - secondary brake shoe
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