Nissan Datsun 521 620 Pick Up 1969 73 Brake Repair Guide

For Models:

• 521 Pickup (1969-72)
• 620 Pickup (1973)

DESCRIPTION

Brake system is hydraulically operated, using a tandem master cylinder and a Master-Vac power brake unit. Leading-Trailing shoe/drum brakes are used on all four wheels, with front brakes actuated by a uni-servo wheel cylinder, and rear brakes actuated by a duo-servo wheel cylinder. Parking brake is cable actuated, operating secondary shoes of rear brake assemblies

ADJUSTMENT

BRAKE PEDAL

Loosen stop light switch adjusting nuts and rotate switch until pedal height, measured from pedal pad to floor, is approximately 5.5". With pedal height adjusted, adjust brake pedal push rod adjusting nut so that .039-.118" free play is obtained when depressing pedal. With pedal assembly properly adjusted, total pedal travel should be 4.96-5.20" with no interference.

BRAKE SHOES

Remove rubber boot from hole in front of backing plate and lightly top adjuster housing to move it forward. Using a suitable brake adjusting tool, turn adjuster downward until drum locks, then back off until drum is free to rotate. Adjustment procedure for rear brakes is the same, with parking brake fully released.

PARKING BRAKE

With parking brake lever applied 3.15-3.94", adjust equalizer link with adjusting nut until rear wheels are locked. Release parking brake and insure rear wheel turn freely.

HYDRAULIC SYSTEM BLEEDING

Attach a bleed tube to wheel cylinder bleeder screw, and immerse opposite end into a container partially filled with brake fluid. Pump brake pedal two or three times, open bleeder screw to allow air to escape, then close bleeder screw. Continue operation until air is no longer seen in discharged fluid. Repeat procedure on remaining brake lines. Bleed rear wheels first, front wheels last.

REMOVAL & INSTALLATION

BRAKE SHOES

Removal (Front) - Remove tire, wheel and brake drum. Disconnect all mounting and return springs.

FRONT BRAKE ASSEMBLY

Remove brake shoes. Remove backing plate pug, spring plate, lock plate, shim and adjuster assembly

Installation - Reverse removal procedure. NOTE - Apply a thin coat of suitable brake grease to pivot points on backing plate adjuster and spring sliding surfaces.

Removal (Rear) - Remove rear wheel and brake drum. Remove mounting springs, clips and pins. Spread shoe assembly and remove parking brake strut. Disconnect return springs and parking brake cable, then lift off brake hoses. Remove adjuster assembly from backing palte.

Installation - Reverse removal procedure. See NOTE in preceding installation procedure.

WHEEL CYLINDER

Removal (All) - With brake shoes removed, disconnect hydraulic line from cylinder and nuts attaching cylinder to backing plate. Remove wheel cylinder.

REAR BRAKE ASSEMBLY

Installation - Reverse removal procedure, adjust brake shoes, and bleed hydraulic system.

MASTER CYLINDER

Removal - Disconnect hydraulic lines from master cylinder, taking care not to spill brake fluid on point. Remove nuts attaching master cylinder to power unit and remove cylinder.

Installation - Reverse removal procedure and bleed hydraulic system.

POWER BRAKE UNIT

Removal - With master cylinder removed, disconnect vacuum line from power unit. From inside vehicle, disconnect brake pedal return spring, power  unit push rod clevis from brake pedal, and remove nuts attaching power unit to firewall. Remove power unit from engine compartment.

Installation - Reverse removal procedure, adjust brake pedal assembly, and bleed hydraulic system.

Push Rod Adjustment - Adjust master cylinder push rod height to .394-.413", measured from tip of push rod to master cylinder mounting surface of power unit.

Check Valve Replacement - Vacuum check valve is located in vacuum line between intake manifold and power unit. To remove, loosen hose clamps, separate hoses from valve, and remove check valve. To install, reverse removal procedure.

OVERHAUL

WHEEL CYLINDER

MASTER CYLINDER ASSEMBLY (LATE MODEL)

Disassembly (All) - Remove snap ring and rubber dust boots. Remove piston and seal assemblies, then remove seals from pistons.

Cleaning & Inspection - Clean all parts in clean alcohol or brake fluid. NOTE - DO NOT use mineral based solvents. Inspect all parts for wear or damage; replace parts as necessary. Check clearance between piston and cylinder bore, if clearance exceeds .006", replace cylinder or piston as necessary.

Reassembly - Reverse disassembly procedure and note the following: Coat all parts with clean brake fluid when reassembling. When securing connector bolt, insert location tip to hole of wheel cylinder firmly and tighten securely.

Disassembly - Remove reservoir caps and drain fluid. Remove retaining ring and secondary piston stop bolt, then withdraw stop washer, primary piston assembly, secondary piston assembly, and return springs. Remove valve caps and check valve assemblies. NOTE - DO NOT remove reservoir. If removed, a new replacement reservoir must be installed.

MASTER CYLINDER ASSEMBLY (EARLY MODEL)

Cleaning & Inspection - Clean all parts in alcohol or brake fluid. Inspect all parts for wear, deformation, or other pistons and cylinder bore; if greater than .006", replace parts as necessary. NOTE - Manufacturer recommends replacing cups and valves whenever master cylinder has been disassembled.

Reassembly - Reverse disassembly procedure and note the following: Coat all parts with brake fluid or rubber grease when reassembling to prevent damage. Replace all gaskets and packings with new parts.

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Nissan Pathfinder R50 1998 Repair Manual

Manufacturer: Nissan
Model: Pathfinder
Year: 1998


Quick Reference Index:

• General Information
• Maintenance
• Engine Mechanical
• Engine Lubrication and Cooling Systems
• Engine Control System
• Accelerator Control, Fuel and Exhaust Systems
• Clutch
• Manual Transmission
• Automatic Transmission
• Transfer 
• Propeller Shaft and Differential Carrier
• Front and Rear Axle
• Front and Rear Suspension
• Brake System
• Steering System
• Restraint System
• Body and Trim
• Heater and Air Conditioner
• Starting and Charging System
• Electrical System
• Alphabetical Index

DOWNLOAD

File Size: 43 MB

File Type: PDF, ZIP

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Datsun Nissan 280Z 1975 Brake Repair Manual

DESCRIPTION

Brake system is hydraulically operated, using a tandem master cylinder and a Master-Vac power brake unit. Front brakes are Girling-Sumitomo dual piston fixed caliper disc type, and rear brakes are leading-trailing shoe/drum type. Brake system is equipped with a proportioning valve to prevent premature locking of rear wheels. Parking brake is mechanically actuated, operating sliding wheel cylinders of rear brake assemblies.

ADJUSTMENT

BRAKE PEDAL

Loosen lock nut, turn push rod clevis, and adjust push rod length so that height of pedal, measured from pedal pad to floor is 8.11" (206 mm). NOTE - Make sure pedal stopper (stop light switch) does not contact pedal arm at this time. With push rod adjusted, adjust stop light switch until pedal height is reduced to 7.99" (203 mm).

FRONT DISC BRAKE PADS

Front disc brakes are self-adjusting, therefore, no adjustment in service is required.

REAR DRUM BRAKE SHOES

Rear drum brakes are self-adjusting (actuated by parking brake), therefore, no adjustment in service is required.

PARKING BRAKE

With parking brake lever fully released, make sure distance between wheel cylinder lever pin hole center and buffer plate on brake assembly backing plate is .453 - .492". Reduce play in linkage by turning adjusting nut on front parking brake operating rod.

REMOVAL & INSTALLATION

FRONT DISC BRAKE PADS

Removal - Remove tire and wheel. Remove clip, retaining pin, danger spring and remove pad with shim.

Installation - Depress piston into cylinder so new pad may be inserted. Install pad, shim, damper spring and retaining pin securing with clip. Depress pedal several times to position new pads.

FRONT DISC BRAKE CALIPER

Removal - With disc pads removed, disconnect hydraulic line from caliper and plug openings. Remove caliper mounting bolts and separate caliper from steering knuckle and rotor.

Installation - Reverse removal procedure, tighten caliper mounting bolts securely, and bleed hydraulic system

FRONT DISC BRAKE ROTOR

Removal - With caliper assembly removed, remove wheel hub dust cap, cotter pin, and adjusting nut. Remove wheel hub and rotor assembly, wheel bearing, and washer from spindle as an assembly. Remove bolts attaching rotor to wheel hub and detach rotor.

Installation - Reverse removal procedure and adjust front wheel bearings.

REAR BRAKE SHOES

Fig. 1 Rear Drum Brake Exploded View

Removal - Remove tire, wheel and drum. NOTE - Should drum be difficult to remove. Remove clevis pin from wheel cylinder lever and disconnect handbrake cable. Remove backing plate rubber boot and loosen brake shoes, (adjust star downward). Some difficulty may be incurred due to adjuster lever. Remove return springs, mounting springs, clips and pins.

Installation - Reverse removal procedure and note the following: Apply brake grease (or equivalent) to wheel cylinder, backing plate, and adjusting plate sliding surfaces, also lubricate wheel cylinder lever fulcrum and ensure wheel cylinder assembly operates freely.

MASTER CYLINDER

Removal - Disconnect hydraulic lines from master cylinder, remove nuts attaching cylinder to power unit, and separate master cylinder from power brake unit.

Installation - Reverse removal procedure, adjust brake pedal height, and bleed hydraulic system.

POWER BRAKE UNIT

Fig. 2 Master Cylinder Reservoir, Body
and Piston Assemblies

Removal - Disconnect power unit push rod from brake pedal by removing clevis pin. Disconnect hydraulic lines from master cylinder, vacuum line from power unit, remove master cylinder mounting 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 Replacement - 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, separate hoses from valve, and remove check valve. To install, reverse removal procedure.

OVERHAUL

FRONT DISC BRAKE CALIPER

Disassembly - Clean exterior of brake caliper. Remove retaining ring and dust seal. Using a small block

Fig. 3 Exploded View of Front Disc Brake Caliper

of wood (or equivalent), hold one piston and blow air into brake line inlet to force piston from bore. Remove piston in similar manner.

Cleaning & Inspection - Clean all parts in alcohol or brake fluid. CAUTION - DO NOT use mineral based solvents. Inspect caliper bores for wear, rust, corrosion or other damage; minor deposits or scratches may be removed with fine emery cloth. Check piston for wear or damage. NOTE - DO NOT use abrasives on piston plated surfaces.

Reassembly - NOTE - Manufacturer recommends replacing rubber parts whenever caliper is being overhauled. Coat piston seal with rubber grease and install into caliper bore. Install dust seal on piston, insert piston into caliper, and install remaining ring. Install opposite piston assembly in same manner.

REAR WHEEL CYLINDER

Disassembly - Remove snap ring and dust cover. Withdraw piston and seal assembly, adjuster wheel,

Fig. 4 Disassembled View of Wheel Cylinder

adjuster screw, and spring.

Cleaning & Inspection - Clean all parts in alcohol or brake fluid. CAUTION - DO NOT use mineral based solvents. Check all parts for wear or damage; replace parts as necessary. Check clearance between cylinder bore and piston, if clearance exceeds .006", replace cylinder or piston as necessary. Check spring for damage or distortion. NOTE - Manufacturer recommends replacing seal whenever wheel cylinder has been disassembled.

Reassembly - Reverse disassembly procedure and note the following. Apply rubber grease to all parts when reassembling to prevent damage.

MASTER CYLINDER

Disassembly - Remove reservoir filler caps, drain brake fluid, and remove secondary piston stop bolt. Remove snap ring and withdraw primary piston, secondary piston and return springs. Remove valve caps and withdraw check valve assemblies. NOTE - Do not remove reservoirs unless necessary

Cleaning & Inspection - Clean all parts in alcohol or brake fluid and inspect for wear or damage. Check clearance between cylinder bore and pistons, if clearance exceeds .006", replace cylinder bore and piston as necessary NOTE - Manufacturer recommends replacing piston cups, gaskets, and valves whenever master cylinder has been disassembled.

Reassembly - Reverse disassembly procedure and note the following: Apply rubber grease to all rubber parts and brake fluid to remaining parts when assembling to prevent damage.

POWER BRAKE UNIT

Disassembly - 1) Place power unit in a soft jawed vise with operating rod pointing up. Scribe alignment marks on front and rear shells to assure reassembly in original position. Remove operating rod lock nut and clevis, then remove dust boot from rear shell.

2) Place a suitable wrench (ST08080000) over rear shell mounting studs. Press down on wrench while rotating diaphragm plate assembly, diaphragm spring and push rod assembly. Pry off retainer and remove bearing and valve body seat from rear shell.

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, the npress in on plunger and shake out stop key. Remove reaction disc from plate assembly. Detach flange from front shell and remove plate and seal assembly

Cleaning & Inspection - Clean all parts in denatured alcohol and blow dry with compressed air.

Inspect inside of front and rear shells for wear or damage and replace as necessary. If slight rust is found on inside surface of shells, polish clean with fine emery cloth. Inspect all parts for cracks, nicks, distortion or other damage and replace as necessary.

Reassembly - Reverse disasembly procedure and note the following: Apply a thin coat of silicone grease to parts before installation. When assembling front shell to rear shell ensure marks made at disassembly are aligned. After reassembly, measure distance from master cylinder mounting surface to end of power unit push rod; distance should be .38-.39" (9.8 - 10.0 mm), if distance is not to specifications, correct by adjusting end of push rod

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