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ATASA 5 TH Study Guide Chapter 49 Pages: 14571480 Drum Brakes 42 Points
ATASA 5 th Drum Brake Systems Please Read The Summary
Before We Begin…
Keeping in mind the Career Cluster of Transportation , Distribution & Logistics
Ask yourself:
What careers might be present in this slide series?
What careers might interest me?
How do these careers relate to my other high school classes?
What career cluster is my 4year plan preparing me for?
1. Since they can handle 2040% of passenger car braking and can be built with a simple __________ brake mechanism, drum brakes continue to be often used for rear wheel brakes.
Drum Disc Parking
ATASA 5 th Drum Brake Systems
2. Drum brakes selfmultiply their force (called ________ _____________) due to a wedging action caused when the shoe tends to follow the rotating drum and is stopped by the anchor pin or plate.
SelfEnergizing ServoAction SuperOptimization
ATASA 5 th Drum Brake Systems
3. Brake shoes and their associated “hardware” are mounted to a steel ______________ plate.
Mounting Backing Packing
ATASA 5 th Drum Brake Systems
4. The brake shoe ____ & rim are the steel parts to which the lining is attached.
Well Web Support
ATASA 5 th Drum Brake Systems
5. The ________ on the brake shoe rim ride against the backing plate & should be lightly lubricated.
Nubs Nibs Nobs
ATASA 5 th Drum Brake Systems
6. The __________ or leading shoe is the one towards the ______ of the vehicle
Primary, Front Secondary, Rear Parking, Center
ATASA 5 th Drum Brake Systems
7. The ___________ or trailing shoe is the one towards the ____ of the vehicle.
Primary, Front Secondary, Rear Parking, Center
ATASA 5 th Drum Brake Systems
8. An ____________ pin limits rotation of the shoes on the backing plate. Anchor pin @top = servo brakes
Anchor Holddown Retaining
ATASA 5 th Drum Brake Systems
9. Brake linings are fastened to the shoe webs by either _________ or ____________ means.
Riveting, Bonding Screwing, Gluing Welding, Soldering
ATASA 5 th Drum Brake Systems
10. Colorcoded ____ (retracting) springs attach the shoes to the anchor pins.
SelfAdjuster Hardware Kit
Return Springs
Holddown Springs Return HoldDown SelfAdjuster
ATASA 5 th Drum Brake Systems
11. ____________ springs or other anchor hardware hold the brake shoes against the backing plate.
Return HoldDown SelfAdjuster
ATASA 5 th Drum Brake Systems
12. The inability of drum brakes to ____________________ heat causes brake fade and is the main reason that disc brakes have replaced drum brakes at the front of cars & trucks.
Dissipate Hesitate Obliterate
ATASA 5 th Drum Brake Systems
13. ________________ drum brakes have doubleended wheel cylinders and an anchor pin at the top of the backing plate which allows the shoes to bite deeper (self energize) into the drum as it rotates and then push (servoact) the secondary shoe against the anchor pin.
Duoservo Uniservo Nonservo
ATASA 5 th Drum Brake Systems
14. In normal forward braking, the friction developed by the _______________ lining is greater than the primary lining due to servoaction, so the secondary shoe is thicker w/more surface area.
Secondary Primary Center
ATASA 5 th Drum Brake Systems
15. Self ______________ (automatic) designs can be either cable or leveroperated variations.
Adjusting Assembling Engaging
ATASA 5 th Drum Brake Systems
16. __________ drum brakes are often known as leadingtrailing shoe systems. They have no servoaction. The anchor is located at the bottom of the backing plate & wheel cylinder at the top.
Duoservo Uniservo Nonservo
ATASA 5 th Drum Brake Systems
17. Quality brake work begins w/a road test to verify customer complaint, a thorough _____________ using a checklist, diagnosis, and finally a complete job with replacement of all faulty components.
ATASA 5 th Drum Brake Systems
18. __________________ is often the first indication of wear problems & the #1 customer brake complaint.
Heat Noise Grabbing
ATASA 5 th Drum Brake Systems
19. In every case, a road test must be done _______________ brake work to ensure proper operation! “Check your work when complete”
Before During After
ATASA 5 th Drum Brake Systems
20. Tire, steering, suspension & wheel bearing problems can all cause vehicles to pull. True or False
ATASA 5 th Drum Brake Systems
21. It may be necessary to unadjust the brake shoes and also backoff the ________________ brake adjustment in order to remove the brake drums since they may have an internal ridge from wear.
Drum Disc Parking
ATASA 5 th Drum Brake Systems
22. Selfadjusters can be accessed through an adjusting ________ in the backing plate so they can be loosened in order to make drum removal easier. Use a thin screwdriver or a special tool for this.
Slot Gouge Dimple
ATASA 5 th Drum Brake Systems
ATASA 5 th Drum Brake Systems
This unadjusts the shoetodrum fit
ATASA 5 th Drum Brake Systems
23. Push nuts or __________ ________ are used during manufacture for temporarily holding drums on to hubs. It is ok to discard them once they are removed in the shop.
Speed Nuts Peanuts Mixed Nuts
ATASA 5 th Drum Brake Systems
24. Leaking wheel cylinders and rear _________ seals must be repaired before replacing brake shoes.
Axle Disc Drum
ATASA 5 th Drum Brake Systems
ATASA 5 th Drum Brake Systems
ATASA 5 th Drum Brake Systems
25. Damaged drums can be machined by turning or grinding on a brake _____________. Maximum outofround of brake drums should never exceed .006” (pedal pulsation could occur)
Mill Lathe Surface Grinder
ATASA 5 th Drum Brake Systems
26. Drum maximum inside diameter should never exceed___________ over original size. ( .060” = 1.5 mm ) Some drum discard diameters are .090” or .2.mm over the standard inside diameter
.060”
.020”
.005”
ATASA 5 th Drum Brake Systems
27. Drum I.D. must be kept within .010” of each other for equal sidetoside braking. True or False
ATASA 5 th Drum Brake Systems
28. Machining the inside diameter of drums changes the liningtodrum fit (arc). True or False
ATASA 5 th Drum Brake Systems
29. Arc, radius, offset, contour, eccentric or _________ ground brake shoes provide a better fit into drums that have been machined oversize to restore proper friction surfaces.
ATASA 5 th Drum Brake Systems
Yam Cam Ram
Oversized drum fitted to std. shoes results in reduced contact area
and brake heat fade
ATASA 5 th Drum Brake Systems
30. Freshly machined as well as brand new drums must be cleaned with special ____________ solvent or with warm, soapy water and then wiped clean with a lintfree cloth. (This applies to rotors too!)
Brake Asbestos Windex®
ATASA 5 th Drum Brake Systems
Nondrive wheel bearings are often repacked while brakes are being serviced.
ATASA 5 th Drum Brake Systems
31. Backing plate support pads & selfadjuster threads should be lightly __________ during assembly.
Lubed Oiled Ground
ATASA 5 th Drum Brake Systems
32. Final brake adjustment goes quicker if a brake shoe ______ gauge matches shoe to drum diameter.
Adjust Micrometer Set
ATASA 5 th Drum Brake Systems
33. Peel back wheel cylinder ______ ________ to reveal leaks & also check for sticking pistons.
Dust Boots Inner Seals Pistons
ATASA 5 th Drum Brake Systems
34. Dripping wheel cylinders can be either replaced or honed and ______________ with new parts.
Rebuilt Recycled Recorded
ATASA 5 th Drum Brake Systems
35. _______________ brakes can be either hand or foot operated, and are usually mechanical systems. Parking brakes can be vacuum released or mechanically released.
Drum Disc Parking
ATASA 5 th Drum Brake Systems
36. Parking brake cables pull on the internal _________ & _________ mechanism of each rear brake.
Lever & Strut Disc & Drum Pulley & Wedge
ATASA 5 th Drum Brake Systems
Parking Brake Strut
Parking Brake Lever
37. Parking brake systems use levers to multiply driver physical effort: 1) the pedal or hand assembly, 2) the ___________________ lever, 3) the parking brake lever & strut inside the drum.
Equalizer Maximizer Minimizer
1
3
2
ATASA 5 th Drum Brake Systems
38. Parking brake adjustment is the last adjustment after all other brake work is done. True or False
ATASA 5 th Drum Brake Systems
39. Parking brakes should hold the vehicle from rolling in either direction on a ______ º (degree) incline.
90º 60º 30º
ATASA 5 th Drum Brake Systems
ATASA 5 th Drum Brake Systems
ATASA 5 th Drum Brake Systems
ATASA 5 th Drum Brake Systems
ATASA 5 th Drum Brake Systems
ATASA 5 th Drum Brake Systems
ATASA 5 th Drum Brake Systems
ATASA 5 th Drum Brake Systems
ATASA 5 th Drum Brake Systems
ATASA 5 th Drum Brake Systems
ATASA 5 th Drum Brake Systems
ATASA 5 th Drum Brake Systems
ATASA 5 th Drum Brake Systems