Systems Repair Worksheet Chapter 45 Pages 1156-1176 Name_______________________
Drum Brakes 39 Points Due Date________
1. Since they can handle 20-40% of passenger car braking and can be built with a simple __________
brake mechanism, drum brakes continue to be often used for rear wheel brakes.
2. Drum brakes actually self-multiply their force due to a _____________ action caused when the
shoe tends to follow the rotating drum and is stopped by the anchor pin. (either at top or bottom)
3. Brake shoes and their associated hardware are mounted to a steel _________________ plate.
4. The brake shoe _____ is the steel part to which the lining is attached. The nibs ride on the backing plate
5. The ______________ or leading shoe is the one towards the __________ of the vehicle
6. The __________________ or trailing shoe is the one towards the ________ of the vehicle.
7. An ____________ pin limits rotation of the shoes on the backing plate. Anchor pin @top = servo brakes
8. Linings are fastened to the shoe webs by either ______________ or ____________ means.
9. Color-coded ______________ (retracting) springs attach the shoes to the anchor pins.
10. ________-________ springs hold the brake shoes against the backing plate.
11. 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.
12. ______-__________ drum brakes have double-ended 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 (servo-act) the secondary shoe against the anchor pin.
13. In normal forward braking, the friction developed by the ___________________ lining is greater
than the primary lining due to servo-action, so the secondary shoe is thicker w/more surface area.
14. Self ____________________ (automatic) designs can be either cable or lever-operated variations.
15. ________________ drum brakes are often known as leading-trailing shoe systems. They have no
servo-action due to the anchor located at the bottom and the wheel cylinder located at the top.
16. Quality brake work begins w/a road test to verify customer complaint, a thorough _____________
using a checklist, diagnosis, and finally a complete replacement of all faulty components.
17. _____________ is often the first indication of wear problems & the #1 customer brake complaint.
18. In every case, a road test must be done _______________ brake work to ensure proper operation.
19. Tire, steering, suspension & wheel bearing problems can all cause vehicles to pull. True or False
20. In some cases, ________________ brakes must be unadjusted in order to remove the brake drums.
21. __________ ________ are used during manufacture for temporarily holding drums on to hubs.
It is ok to discard them once they are removed in the shop.
22. Self-adjusters can be accessed through an adjusting ________ in the backing plate so they can be
loosened in order to make drum removal easier.
23. Leaking wheel cylinders and rear _________ seals must be repaired before replacing brake shoes.
24. Damaged drums can be machined by either turning or grinding on a brake _____________.
25. Drum maximum inside diameter should never exceed ________ over original size. (1.5 mm)
Some drum discard diameters are .090” or .2.mm over the standard inside diameter
26. Drums I.D. must be kept within .010” of each other for equal side-to-side braking. True or False
27. Machining the inside diameter of drums changes the shoe-to-drum fit (arc). True or False
28. Freshly machined as well as brand new drums must be cleaned with special ____________ solvent
or with warm, soapy water.
29. Non-drive wheel bearings are often serviced while brakes are being serviced. True or False
30. 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.
31. Backing plate support pads & self-adjuster threads should be lightly __________ during assembly.
32. Final brake adjustment can be expedited by use of a brake ____________ gauge. (shoe-set gauge)
33. Peel back wheel cylinder ________ __________ to reveal leaks during brake inspections.
34. Dripping wheel cylinders can be either replaced or honed and ______________ with new parts.
35. _______________ brakes can be either hand or foot operated, but are always mechanical systems.
36. Parking brake cables pull on the internal _________ & _________ mechanism of each rear brake.
37. Parking brake systems use ___ levers to multiply driver physical effort; 1) the pedal or hand
assembly, 2) the ____________________ lever, and the parking brake lever inside the drum.
38. Parking brake adjustment is the last adjustment after all other brake work is done. True or False
39. Parking brakes should hold the vehicle from rolling in either direction on a ______ degree incline.