Drum Brakes

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Drum Brakes
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Two different categories of drum brakes

• Non-servo

• Servo

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Non-Servo

• On Front Wheel Drive (FWD) vehicles it is
  necessary to have a more ineffective brake on
  the rear of the car.

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Non-Servo
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Servo Action

• The rear shoe does most of the work
• Wedging action

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• Non Servo brake lining
• Servo Brake lining
• Primary
• Secondary

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It is very important that the Primary shoe is
always facing toward the front of the car
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The Secondary shoes always face toward the rear
of the car
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Drum Removal

• Groves from the rivets wearing into the drum.
• The last brake job...the drums werent turned

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Drum Removal
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Drum Removal
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Things To Look For
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Worn Drums

• Scored
• Bell Mouthed
• Concaved

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Max. Drum size

• Why is this important

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Check the Wheel Cylinders for leaks
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Adjusters

• Check them for wear
• Frozen

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Axle Seals

• Inside Leak
• Outside Leak

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