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SECTION 4E

REAR DRUM BRAKES

DESCRIPTION AND OPERATION

DRUM BRAKES

This drum brake assembly is a leading/trailing shoe design. Both brake shoes are held against the wheel cylinder pistons by the lower return spring and the fixed anchor plate near the lower return spring. When the brakes are applied, the wheel cylinder pistons move both shoes out to contact the drum. With forward wheel rotation, the forward brake shoe will wrap into the drum and become self-energized. With reverse wheel rotation, the rear brake shoe is self-energized. Force from the brake shoes is transferred to the anchor plate through the backing plate to the axle flange. Adjustment is automatic and occurs on any service brake application. Do not switch the position of shoes that have been in service, as this may render the self-adjustment feature inoperative and result in increased pedal travel.
Notice :

COMPONENT LOCATOR

REAR DRUM BRAKES


D107C401
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  1. Bleeder Screw
  2. Bleeder Screw
  3. Rear Brake Assembly
  4. Rear Brake Plate
  5. Wheel Cylinder
  6. Strut Assembly
  7. Brake Leading Shoe
  8. Middle Return Spring
  9. Upper Return Spring
  10. Brake Shoe Retain Spring Pin
  11. Trailing Shoe
  12. Brake Shoe Retain Spring
  13. Brake Shoe Retain Spring Cap
  14. Lower Return Spring
  15. Hub Bolt
  16. Rear Brake Drum

DIAGNOSTIC INFORMATION AND PROCEDURES

REAR DRUM BRAKE

Condition
Probable cause
Correction
Not Enough Braking Force
  • Badly worn brake shoe lining.
  • Replace the lining.
  • Lining stained with oil.
  • Check the wheel cylinder leaks and then replace the wheel cylinder or the lining, if needed.
  • Wheel cylinder condition faulty.
  • Replace the wheel cylinder.
  • Malfunctioning self-adjustment feature.
  • Repair the self-adjustment feature.
Uneven Braking
  • Lining stained with oil.
  • Check the wheel cylinder leaks and then replace the wheel cylinder or the lining, if needed.
  • Wheel cylinder condition faulty.
  • Replace the wheel cylinder.
  • Malfunctioning self-adjustment feature.
  • Repair the self-adjustment feature.
Dragging Brakes After Pedal is Released
  • Weakened brake shoe return spring.
  • Replace the brake shoe return spring.
  • Wheel cylinder condition faulty.
  • Replace the wheel cylinder.
Excessive Pedal Travel
  • Excessively worn lining.
  • Replace the lining.
  • Malfunctioning self-adjustment feature.
  • Repair the self-adjustment feature.
Braking Noise or Vibration
  • Foreign material stuck to drum.
  • Clean the rear drum brake.
  • Loosen brake plate bolt.
  • Tighten the brake plate bolt.
  • Damaged drum.
  • Replace the drum.
Poor Braking Force of Parking Brake
  • Lining stained with oil.
  • Check the wheel cylinder leaks and then replace the wheel cylinder or the lining, if needed.
  • Damaged self-adjustment feature.
  • Repair the self-adjustment feature.
  • Poor adjustment of parking brake cable.
  • Adjust the parking brake cable.

DRUMS

Inspect the brake drum as follows;
  1. Inspect the lining for wear or stain with oil.
  2. Measure the inside diameter.
Unit : mm (in.)
Inside Diameter Wear Limit Value
182 (7.165)

D107C301
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  1. If the measured value is over the limit value, or if the defect is found, replace the drum.

LINING

Inspect the brake drum as follows ;
  1. Inspect the drum for crack or damage.
  2. Measure the thickness.
Unit : mm (in.)
Lining Wear Limit Value
1 (0.039)

D107C302
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  1. If the measured value is within the limit value, or if the defect is found, replace the lining.

REPAIR INSTRUCTIONS

ON-VEHICLE SERVICE



D107C501
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REAR BRAKE DRUM

Removal Procedure

  1. Remove the rear wheels. Refer to Section 6E, Tires and Wheels.
  2. Release the parking brake.
  3. Remove the brake drum.


  4. D17C502A
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    Important : Do not reuse removed hub bolts.



D107C503
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Installation Procedure

  1. Install the brake drum.


  2. D17C504A
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  3. Adjust the parking brake.
  4. Install the rear wheels. Refer to Section 6E, Tires and Wheels.


D107C505
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BRAKE SHOE

Removal Procedure

  1. Remove the brake drum. Refer to "Brake Drum" in this section.
  2. Remove the return spring.


  3. D107C506
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    D107C507
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  4. Remove the brake shoe.


  5. D107C508
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  6. Disconnect the parking brake cable from the trailing shoe and remove the trailing shoe (7).


D107C509
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Installation Procedure

  1. Install in the reverse of removal.
  2. Clean the adjust assembly and apply grease.
  3. Connect the parking brake cable from the trailing shoe.
  4. Install the brake shoe.
  5. Install the return spring.
  6. Install the brake drum. Refer to "Brake Drum" in this section.


D107C510
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WHEEL CYLINDER ASSEMBLY

Removal Procedure

  1. Remove the brake drum. Refer to "Rear Brake Drum" in this section.
  2. Remove the wheel cylinder.


  3. D107C511
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D17C512A
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Installation Procedure

  1. Install the wheel cylinder to the backing plate with the wheel cylinder bolt (1).
  2. Tighten
    Tighten the wheel cylinder-to-backing plate bolt to 10 N•m (89 lb-in).

  3. Connect the brake line fitting (2).
  4. Tighten
    Tighten the brake line fitting to 16 N•m (12 lb-ft).

  5. Install the brake shoe. Refer to "Brake Shoe" in this section.
  6. Install the brake drum. Refer to "Rear Brake Drum" in this section.


D107C513
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BACKING PLATE

Removal Procedure

  1. Remove the brake drum. Refer to "Rear Brake Drum" in this section.
  2. Remove the brake shoe components. Refer to "Brake Shoe" in this section.
  3. Remove the wheel cylinder assembly. Refer to "Wheel Cylinder Assembly" in this section.
  4. Remove the bolts and the backing plate.


D17C514A
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Installation Procedure

  1. Install the bolts and the backing plate.
  2. Tighten
    Tighten the backing plate-to-rear axle bolts to 24 N•m (18 lb-ft).

  3. Install the wheel cylinder assembly. Refer to "Wheel Cylinder Assembly" in this section.
  4. Install the brake shoe components. Refer to "Brake Shoe" in this section.
  5. Install the brake drum.

UNIT REPAIR



D107C701
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WHEEL CYLINDER

Disassembly Procedure

  1. Remove the wheel cylinder assembly. Refer to "Wheel Cylinder Assembly" in this section.
  2. Disassemble wheel cylinder assembly.
  3. Clean all parts with denatured alcohol. Dry the parts with unlubricated compressed air.


D17C702A
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Assembly Procedure

    Important : Lubricate the new seals, the piston, the piston cup and the wheel cylinder bore with clean brake fluid before assembly.

  1. Assemble wheel cylinder assembly.
  2. Tighten
    Tighten the bleeder screw to 6 N•m (53 lb-in).

  3. Inspect the piston for free movement.
  4. Install the wheel cylinder assembly. Refer to "Wheel Cylinder Assembly" in this section.

SPECIFICATIONS

GENERAL SPECIFICATIONS

Application
Unit
Description
Drum
Inside Diameter
mm (in.)
180 (7.086)
Wear Limit
mm (in.)
182 (7.165)
Out of Round
mm (in.)
0.04 (0.001)
Cylindricty
mm (in.)
0.02 (0.0008)
Brake Lining
Thickness
mm (in.)
4 (0.157)
Wear Limit
mm (in.)
1 (0.039)
Distance Between Lining and Drum
mm (in.)
0.3 (0.011)
Wheel Cylinder
Inside Diameter
mm (in.)
17.46 (0.687)

FASTENER TIGHTENING SPECIFICATIONS

Application
N•m
Lb-Ft
Lb-In
Castellated Nut*
-
-
-
Wheel Cylinder Bolt
10
-
89
Brake Backing Plate Bolt
24
18
-
Brake Pipe Fitting
16
12
-
Bleeder Screw
6
-
53
*Castellated Nut : 25 N•m - 180° + 2.5 N•m (18 lb-ft - 180° + 22 lb-in.)


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