Parking brakes for Rear Disc brake


Thread Starter #1
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Basics, Pros & Cons of Disc brake : Service + Parking

Cars with disc brakes (all 4 wheels, especially the rear) has two types of parking brakes

1) Combined Caliper Disc
0900c152800b8a3f.gif
brakes9.gif
This type is commonly used, which operates service brakes through hydraulic fluid & mechanically operated parking brake.
Pros:
-Light weight
-Low cost
-Narrow wheel bearings
Cons:
-Complicated caliper design
-Reliability: After running brake disc & pads are hot and expanded. When the vehicle is stopped with parking brake, disc & pad cools and contracts. Result- Less braking efficiency.

2) Drum In-Hat brake (DIH)
0309sr_reardisc_20_z.jpg
This type has a disc & caliper for service brake and traditional drum & shoe for parking brake. Drum & disc are a single unit. Hydraulic fluid operated disc service brakes & mechanically operated drum parking brakes.
Pros:
-Parking brakes can be used as emergency brakes in case of service brake failure
-No effect of disc & pad heating & cooling
Cons:
-More cost
-More mass
-Wider wheel bearings to accommodate the increase in length (drum)
 

350Z

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Another informative thread. The shoe of my car's drum brakes on rear was stuck when it was parked for long with handbrake engaged. Finally had to get it replaced.

Drive Safe,
350Z
 

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Thread Starter #4
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A very nicely explained system. But i guess drum brakes also get heated up n expand while normal braking.
Drum brakes also get heated up, in fact more than the disc brakes. That is why the efficiency of drum brakes decreases on down hill driving than disc brakes.

Another informative thread. The shoe of my car's drum brakes on rear was stuck when it was parked for long with handbrake engaged. Finally had to get it replaced.
Culprit is the geometry of shoe to drum contact and the actuation mechanism, normally this happens with the worn our shoes. New shoes may get locked if the brake setting was not proper (i.e., gap between the shoe & drum)
 
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