Mazda Trucks 1972-1986 Repair Guide

Master Cylinder

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REMOVAL & INSTALLATION All Models



  1. Disconnect and plug the fluid outlet line at the outlet fitting on the master cylinder one-way valve.
  2.  
  3. Remove the nuts and bolts attaching the master cylinder to the firewall.
  4.  
  5. Remove the cylinder straight out away from the firewall.
  6.  
  7. Start the pedal pushrod into the master cylinder and position the master cylinder on the firewall.
  8.  
  9. Install the attaching nuts and bolts. Torque the nuts to 12-17 ft. lbs.
  10.  
  11. Connect the fluid outlet line to the master cylinder fitting.
  12.  
  13. Bleed the hydraulic system.
  14.  
  15. Check the clutch pedal free-travel and adjust as necessary.
  16.  

OVERHAUL1972-84 Vehicles



See Figures 1, 2, 3 and 4

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Fig. Fig. 1: 1972-75 piston engine clutch master cylinder



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Fig. Fig. 2: 1976-78 piston engine clutch master cylinder



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Fig. Fig. 3: 1979-84 clutch master cylinder



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Fig. Fig. 4: Rotary engine clutch master cylinder

  1. Remove the master cylinder.
  2.  
  3. Clean the outside of the cylinder thoroughly and drain the fluid.
  4.  
  5. On models through 1975, remove the dust cover.
  6.  
  7. Pry out the piston stop ring and remove the stop washer.
  8.  
  9. Remove the piston, piston cup and spring from the cylinder.
  10.  
  11. On all models except the 1976-78 B1800, carefully remove and disassemble the one-way valve.
  12.  
  13. Clean all parts thoroughly using clean brake fluid.
  14.  
  15. Discard any worn, damaged or misshapen parts.
  16.  
  17. Check the piston-to-bore clearance. Clearance should be 0.15mm (0.0059 in.). If clearance exceeds this figure, replace the unit.
  18.  
  19. If the cylinder bore is lightly scored or brinnelled, it may be honed to restore the finish.
  20.  
  21. Assembly is the reverse of disassembly. Coat all parts with clean brake fluid prior to assembly. On 1976-78 B1800 models, be sure that the compensating port is open. Fill and bleed the system.
  22.  

1986 Vehicles See Figure 5

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Fig. Fig. 5: 1986 clutch master cylinder

  1. Remove the master cylinder.
  2.  
  3. Using snapring pliers, press down on the piston and remove the snapring from the cylinder bore.
  4.  
  5. Remove the piston and secondary cup, primary cup protector, primary cup, return spring, reservoir and bushing.
  6.  
  7. The secondary piston and cup must be blown out with compressed air applied to the fluid pipe hole. Be careful to cover the bore opening with a heavy rag to catch the piston.
  8.  
  9. Inspect all parts for wear or damage. Clean all parts in clean brake fluid.
  10.  
  11. Assembly is the reverse of disassembly. Coat all parts with clean brake fluid prior to assembly.
  12.  

ONE-WAY VALVE REMOVAL & INSTALLATION



A one-way valve is used on all master cylinders except 1976-78 1.8 liter models, which have a compensating port instead.

  1. Remove the cap from the side of the master cylinder.
  2.  
  3. Remove the washer, one-way valve, and the spring.
  4.  
  5. Installation is the reverse.
  6.  

 
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