Mazda Trucks 1972-1986 Repair Guide

Master Cylinder

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See Figures 1 through 14

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Fig. Fig. 1: Exploded view of the early 1972 B1600 master cylinder



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Fig. Fig. 2: Exploded view of the late 1972 through 1975 B1600 master cylinder



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Fig. Fig. 3: Exploded view of the rotary pick-up master cylinder



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Fig. Fig. 4: Exploded view of the 1976 master cylinder



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Fig. Fig. 5: Exploded view of the 1977-78 master cylinder



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Fig. Fig. 6: Exploded view of the 1979-80 master cylinder



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Fig. Fig. 7: Exploded view of the 1981 master cylinder



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Fig. Fig. 8: Exploded view of the 1982-84 B2000 and B2200 master cylinder



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Fig. Fig. 9: Diagram of the guide pin and its usage



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Fig. Fig. 10: Exploded view of the 1986 master cylinder



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Fig. Fig. 11: To remove the master cylinder, remove the brake lines connected to the master cylinder ...



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Fig. Fig. 12: ... then unbolt the master cylinder attaching nuts



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Fig. Fig. 13: On 1986 models, also unplug the fluid level sensor wire



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Fig. Fig. 14: Finally lift the master cylinder off the mounting studs

REMOVAL & INSTALLATION



  1. Remove the brake lines from the master cylinder and cap the lines.
  2.  
  3. On 1986 models, disconnect the fluid level sensor coupling.
  4.  
  5. Unbolt and remove the master cylinder from the firewall or power booster. 1977-84 models have a remotely mounted reservoir, so the lines will have to be unclipped and plugged.
  6.  


WARNING
Clean, high quality brake fluid is essential to the safe and proper operation of the brake system. You should always buy the highest quality brake fluid that is available. If the brake fluid becomes contaminated, drain and flush the system, then refill the master cylinder with new fluid. Never reuse any brake fluid. Any brake fluid that is removed from the system should be discarded.

  1. Installation is the reverse of removal. Torque the mounting nuts to 15 ft. lbs.
  2.  
  3. Bleed the system.
  4.  

OVERHAUL 1972-84 Vehicles



  1. Remove the master cylinder.
  2.  
  3. Drain the fluid. On models through 1976, remove the reservoir.
  4.  
  5. Remove the reservoir grommets from the master cylinder body on models through 1976 or elbow connectors on 1977-84 models.
  6.  
  7. Remove the dust boot.
  8.  
  9. Depress the piston and remove the piston stop ring from the cylinder.
  10.  
  11. Remove the piston stop washer, primary piston, and spring.
  12.  
  13. Loosen, but do not remove, the secondary piston stop screw.
  14.  
  15. Push the secondary piston inward, then remove the stop screw. Insert a guide pin in its place, and remove the secondary piston.
  16.  
  17. Remove the outlet port fittings, check valves and springs.
  18.  
  19. Clean all parts in clean brake fluid.
  20.  
  21. Inspect all parts for wear or damage. Replace any worn, discolored, misshapen or suspect part. The cylinder bore may be honed to remove light scoring, pitting or discoloration. If honing cannot polish the interior, discard the cylinder. Check the piston-to-bore clearance. If the clearance exceeds 0.15mm (0.0059 in.), replace the cylinder.
  22.  
  23. Assembly is the reverse of disassembly. Coat all parts in clean brake fluid before assembly. Use the guide pin to aid in installing the secondary piston. Refill the master cylinder and pump the piston several times, until fluid flows from each outlet port.
  24.  

1986 Vehicles

  1. Rock the reservoir from side-to-side to remove it from the master cylinder.
  2.  
  3. Remove the reservoir grommets.
  4.  
  5. Remove the piston stopper screw from the bottom of the master cylinder.
  6.  
  7. Depress the piston and remove the snapring.
  8.  
  9. Remove the primary piston assembly.
  10.  
  11. Remove the secondary piston assembly. Compressed air applied to the rearmost fluid port may be necessary to remove the secondary piston. If so, place a heavy rag over the cylinder bore to catch the piston.
  12.  
  13. Clean all parts in clean brake fluid.
  14.  
  15. Inspect all parts for wear or damage. Replace any worn, discolored, misshapen or suspect part. The cylinder bore may be honed to remove light scoring, pitting or discoloration. If honing cannot polish the interior, discard the cylinder. Check the piston-to-bore clearance. If the clearance exceeds 0.12mm (0.0047 in.), replace the cylinder.
  16.  

 
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