Front Disc Brakes: Hub/Bearing
The hub/bearing is used to mount front brake rotor and wheel. The rotor is mounted to front face of hub by wheel mounting studs and retained by wheel mounting nuts. The hub/bearing is mounted to steering knuckle using four mounting bolts.
The double pin front disc brake caliper is mounted to caliper adapter, using bushings, sleeves, and caliper guide pin bolts. See Figure . The caliper guide pin bolts thread into caliper adapter. See Fig 1 . The adapter for front disc brake caliper is mounted to front of steering knuckle. The adapter is mounted to steering knuckle using hub/bearing mounting bolts.
The two machined abutments on caliper adapter, position and align caliper fore and aft. The guide pin bolts, sleeves, and bushings control side to side movement of caliper. The piston seal is designed to assist in shoe to rotor clearance.
All forces generated by front brakes, when stopping vehicle, are taken up directly by caliper adapters and steering knuckles. The caliper is a one piece casting with inboard side containing a single piston. The phenolic piston is 60 mm (2.36") in diameter. A square cut rubber piston seal is located in a machined groove in cylinder bore. It provides a hydraulic seal between piston and cylinder wall. See Fig 2 . The molded rubber dust boot mounts in a counter bore of cylinder bore opening and in a groove maintaining proper brake which is machined in outer surface of piston. This prevents contamination of piston and bore area.
As lining wears, reservoir level will go down. If fluid has been added, reservoir overflow may occur when piston is pushed back into new lining position. Overflowing can be avoided by removing a small amount of fluid from master cylinder reservoir.