Disc vs. drum brakes

[karasmer]

I must be missing something but why on earth did automakers and they still do go with drum brakes, they can not be cheaper to make with all the parts involved. I just think of this every time I have to do a rear break job which really sucks compared to front discs.

[Guest Oldengineer]

Drum brakes still show up on the rears because of the cost of the parking brake is cheaper. Cars with rear disc brakes typically use a cable and lever operated screw mechanism to ratchet out the calper's piston or incorporate a small cable operated drum brake assembly that works on a brake drum incorporated into the rear rotors.

Regards:

Oldengineer

[joe_padavano]

Automakers originally used drum brakes because they are self-energizing. This lessened the force required to actuate them, which was important until power brakes became commonplace. Disk brakes are not self-energizing.