DESCRIPTION
Brake system is hydraulically operated, utilizing a tandem master cylinder and a Master-Vac power brake unit. Front disc brakes consist of rotors attached to wheel hubs, and single cylinder, dual piston floating calipers attached to steering knuckles. Rear brakes are leading-trailing shoe/drum type, using a single piston sliding wheel cylinder. Parking brake cable actuated, operating wheel cylinders of rear brake assemblies.
ADJUSTMENT
PEDAL HEIGHT & FREE PLAY
B-210 - Adjust pedal height to specifications by moving stop lamp switch. Pedal height should be 6.14" (156 mm) on vehicles equipped with manual transmission and 6.22" (158 mm) on vehicle with automatic transmission. After pedal height is adjusted, loosen push rod lock nut and adjust pedal free play to .039 - .197" (1-5 mm).
610 - Adjust brake lamp switch bolt until end face is flushed with front face of bracket, then tighten lock nut. Adjust pedal stopper until pedal height, measured from pedal pad to floor, is 7.28" (185 mm). Adjust master cylinder push rod length until free play, measured at pedal, is .039 - 197" (1-5 mm).
FRONT DISC BRAKE PADS
Front disc brakes are self-adjusting, therefore, no adjustment in service is required.
REAR BRAKE SHOES
Raise and support vehicle and remove wheel. Using a suitable brake adjusting tool, tighten adjuster wedge clockwise until brake shoe contacts drum. Check operation by turning drum and applying brakes; if shoe interfere with drum rotation, readjust.
PARKING BRAKE
With rear brakes properly adjusted, adjust parking brake cable turnbuckle until rear brakes are locked when parking brake lever pulled to sixth or seventh ratchet stop. Release parking brake lever and ensurer rear wheels turn freely, and that all parts are returned to their original position
HYDRAULIC SYSTEM BLEEDING
Attach a bleed tube to bleeder screw and immerse opposite end of tube in a container partially filled with brake fluid. Pump brake pedal two or three times, keep pedal fully depressed, open bleeder screw and exhaust air, close bleeder screw, and return brake pedal. Repeat operation until air bubbles are no longer seen in discharged fluid. Repeat procedure on remaining brake lines. Bleeding sequence is left-rear, right-rear, left-front, right-front.
REMOVAL & INSTALLATION
FRONT DISC BRAKE PADS
Removal - Raise front of vehicle and support in place, then remove front wheels. Remove clips from retaining pins and pull out pins, coil springs and pad springs. Remove pads from caliper assembly using a suitable pair of pliers.
Inspection - With friction pads removed, measure their thickness. Replace any pad that is worn to less than .063" (1.6 mm) in thickness (not including metal backing plate). It is recommended that friction pads be replaced as a set to prevent any possibility of uneven braking.
Installation - Clean and apply P.B.C. grease ( or equivalent) on yoke guide groove of cylinder body, sliding contact portions of yoke and end surface of piston. Loosen bleeder screw and push outer piston in cylnder until end surface of piston coincides with end surface of retaining ring on boot. Install inner brake pad. Push inner piston in cylinder by pulling on yoke, then install outer brake pad. After installing pads, depress brake pedal several times to seat pads.
FRONT DISC BRAKE CALIPER
Removal - Raise vehicle and suitably support on safety stands; remove tire and wheel. Remove brake friction as previously described. Disconnect brake line from wheel cylinder. To ease removal of caliper, remove strut assembly and knuckle arm mounting bolt. Withdraw caliper mounting bolt and separate it from strut assembly.
Installation - To install brake caliper assembly, reverse removal procedures, noting the following: Bleed hydraulic system.
FRONT DISC BRAKE ROTOR
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| Fig. 1 Rear Drum Brake Assembly (Model B-210 shown) |
Removal - With caliper removed, remove hub dust cap, cotter pin and nut. Remove hub and rotor assembly with wheel bearing and washer in place. Remove bolts attaching rotor to wheel hub, and separate rotor from hub.
Installation - Reverse removal procedure, tighten hub bolts securely, and adjust wheel bearings.
REAR BRAKE ASSEMBLY
Removal (Rear) - Raise vehicle and suitable support on safety stands; remove tire and wheel. Loosen parking brake linkage at clevis pin and place out of way. Remove brake drum. Remove shoe retainer and return spring, then lift off shoe assembly. Disconnect brake line from wheel cylinder. If necessary, wheel cylinder can now be removed by withdrawing dust cover, adjusting shims and plates.
Inspecting - Inspect all brake components for damage or excessive wear and replace those found defective. Replace brake lining if it is oil soaked or lining is less than .059" (1.5 mm) thick.
Installation - To install rear brake lining, reverse removal procedures, noting the following: Readjust shoe-to-drum clearance and, if necessary, bleed hydraulic system.
MASTER CYLINDER
Removal - Disconnect front and rear brake lines from master cylinder. Remove master cylinder attaching nuts and remove master cylinder.
Installation - To install master cylinder, reverse removal procedures, noting the following: Bleed hydraulic system and check pedal height.
POWER BRAKE UNIT
Removal - Disconnect power unit push rod from brake pedal by removing clevis pin. Disconnect hydraulic lines from master cylinder and vacuum line from power unit, remove master cylinder attaching nuts, and remove master cylinder. Remove nuts attaching power unit to firewall, and remove power unit from engine compartment.
Installation - Reverse removal procedure, adjust brake pedal height, and bleed hydraulic system.
Check Valve Removal - Check valve is located in vacuum line between intake manifold and power unit on firewall. To remove, disconnect retaining clip from firewall, remove hose clamps, spearate hoses from valve and remove check valve. To install, reverse removal procedure.
OVERHAUL
FRONT DISC BRAKE CALIPER
Disassdembly - With caliper removed, drain brake fluid and remove bleeder screw. Push both pistons into cylinder bore, then place yoke in a vise and tap the top of yoke. Remove bias ring from outer piston, then remove retaining rings and boots. Push both pistons out in one direction. Remove piston seals from cylinder and yoke spring from yoke.
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| Fig. 2 Front Disc Brake Caliper Exploded View |
Inspecting - Thoroughly clean all internal parts and check each component for excessive wear or damage. If caliper bore is damaged or excessively rusted, it must be replaced. If however, slight imperfections are evident, honing will eliminate them. It is recommended to replace all seals when overhauling
Reassembly - Before assembling components, lightly coat with suitable brake grease. Insert bias ring into piston so round portion of ring fits to bottom of piston. Insert piston into cylinder. Do not fully seat piston. Install dust boot and retaining ring. Install yoke bias ring so it coincides with yoke groove of cylinder. Fit bias spring to yoke so bias spring faces bleeder side of cylinder. With yoke spring inserted in cylinder groove, properly align position of bias spring so groove of spring aligns with yoke. Assemble body-to-yoke, tapping lightly if necessary.
REAR WHEEL CYLINDER
Disassembly - NOTE - Wheel cylinders can be overhauled without removing from vehicle; do not remove wheel cylinder unless replacement is necessary. To disassemble, remove snap ring and dust boot, then withdraw piston and seal from cylinder bore. Remove seal from piston.
Cleaning & Inspection - Clean and dry all parts and inspect for wear or damage. Measure clearance between piston and cylinder bore; if clearance exceeds .006" (.15 mm), replace piston or cylinder as necessary. NOTE - Manufacturer recommends replacing rubber piston seal whenever wheel cylinder is disassembled.
Reassembly - Reverse disassembly procedure and note the following: Apply a thin coat of rubber grease to all parts when assembling cylinder.
MASTER CYLINDER
Disassembly - Remove master cylinder reservoir caps and filters and drain brake fluid. Using a screwdriver, pry off stopper ring. Remove stopper screw and pull out primary piston assembly, spring and secondary piston assembly. Remove plugs and pull out front and reaer check valves. NOTE - Do not remove reservoir tanks; if tanks are removed for any reason, discard and install new ones.
Inspecting- Thoroughly clean all components in approve grade brake fluid. Inspect all components for excessive wear or damage and replace parts as necessary.
Reassembly - Reverse disassembly procedure and note the following: Coat all parts with brake fluid (rubber parts with brake grease) when assembling.
POWER BRAKE UNIT
Disassembly - 1) Place power unit in a soft jaw vise with operating rod pointing up. Scribe on alignment mark on front and rear shell to assure reassembly in original position, then remove lock nut, clevis and dust boot from rear shell.
2) Place suitable wrench (ST08080000) over rear shell mounting studs. Press down on wrench while rotating counterclockwise and remove rear shell, then lift out diaphragm plate assembly, diaphragm spring and push rod assembly. Pry off retainer and remove bearing and valve body seal assembly.
3) Remove diaphragm from diaphragm plate assembly, then pry off air silencer retainer and remove silencer and filter. Rotate diaphragm plate assembly until valve plunger key slot is down, then press in on plunger and shake out stop key. Remove reaction disc from plate assembly. Detach flange from front shell and remove front seal assembly.
Cleaning & Inspection - Clean all parts in denatured alcohol and blow dry with compressed air. Inspect front and rear shells for wear or damage. If slight rust is found on inside surface of shells, polish clean with fine emery cloth. Inspect all parts fro cracks, nicks, distortion or other damage and replace as necessary.
Reassembly - Reverse diassembly procedure note the following: Apply a thin coat of silicone grease to parts before installation. When assembling front shell to rear shell ensure marks made during diassembly are aligned. After reassembly, measure distance from master cylinder mounting surface of power unit to end of power unit push rod; distance should be .38-.30" (9.8-10.0 mm). If distance is not to specifications, correct by adjusting end of push rod.
