Honda Accord/Prelude 1984-1995 Repair Guide

Master Cylinder

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REMOVAL & INSTALLATION



See Figures 1 and 2


WARNING
Brake fluid is extremely damaging to painted, plastic or rubber surfaces. If any fluid is spilled, immediately flush the area with water. Be prepared to plug brake lines and hoses during disassembly. Dirt and moisture MUST be kept out of the system. Perform workbench operations in a clean, well-lit area.

  1. If equipped with an air bag, disconnect the negative battery cable and properly disable the Supplemental Restraint System (SRS), as detailed in Chassis Electrical .
  2.  
  3. Use a syringe or similar tool to remove as much fluid as possible from the fluid reservoir.
  4.  



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Fig. Fig. 1: Use a syringe or similar tool to remove as much fluid as possible from the fluid reservoir

  1. Label each brake line by its position on the master cylinder. Use flare-nut wrenches to loosen and disconnect the brake lines from the master cylinder. Wipe any spillage immediately to prevent paint damage.
  2.  
  3. Remove the nuts securing the cylinder to the brake booster. Remove the master cylinder.
  4.  



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Fig. Fig. 2: After its retaining nuts are removed, the master cylinder can be removed from the booster

To install:
  1. If the master cylinder has been disassembled or replaced, the pushrod clearance must be checked and adjusted before reinstallation. Refer to the adjustment procedure in this section.
  2.  
  3. Install the master cylinder to the brake booster. Tighten the nuts to 11 ft. lbs. (15 Nm).
  4.  
  5. Reconnect the brake lines. Hand-thread the fittings to avoid stripping the threads; do not move or manipulate the lines to the point of bending or crimping them. Tighten the flare nuts to 11 ft. lbs. (15 Nm).
  6.  
  7. Refill the reservoir with clean, fresh brake fluid. Do not reuse old fluid.
  8.  
  9. Bleed the brake system thoroughly.
  10.  
  11. If equipped, enable the SRS system and connect the negative battery cable.
  12.  

PUSHROD CLEARANCE ADJUSTMENT



See Figures 3, 4 and 5

The use of special tools or their equivalent is required for this procedure. Rod bolt adjustment gauge, Honda tool 07975-SA50000 or equivalent must be used.

  1. Install the adjustment gauge tool on the end of the master cylinder. Adjust the bolt so the top of the gauge is flush with the end of the master cylinder piston.
  2.  



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Fig. Fig. 3: Adjust the bolt so the top of the gauge is flush with the end of the master cylinder piston

  1. Without disturbing the adjusting bolt's position, put the gauge upside down on the booster. Install the nuts and tighten them to 11 ft. lbs. (15 Nm).
  2.  
  3. Install a vacuum gauge and T-fitting into the booster vacuum line. Start the engine; have an assistant maintain an engine speed yielding 20 in. Hg on the vacuum gauge.
  4.  



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Fig. Fig. 4: Install a vacuum gauge and T-fitting into the booster vacuum line

  1. Use a feeler gauge to measure the clearance between the gauge body and the adjusting nut. Correct clearance is 0-0.016 in. (0-0.4mm). If the clearance is incorrect, loosen the star locknut at the back of the booster; turn the adjuster to alter the position. Tighten the locknut securely.
  2.  



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Fig. Fig. 5: Use a feeler gauge to measure the clearance between the gauge body and the adjusting nut

  1. Switch the ignition OFF .
  2.  
  3. Remove the vacuum gauge. Remove the adjusting gauge tool.
  4.  
  5. Install the master cylinder.
  6.  

OVERHAUL



1984-89 Models

See Figures 6, 7, 8, 9, 10 and 11

  1. With the master cylinder removed and the reservoir drained, remove the outer snapring.
  2.  



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Fig. Fig. 6: Push in on the piston assembly and remove the snapring

  1. Remove the washer, secondary cup and secondary piston bushing from the shaft.
  2.  
  3. Remove the stop bolt. Push in on the secondary piston assembly to take tension off the seal.
  4.  



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Fig. Fig. 7: Push in on the piston assembly and remove the stop bolt

  1. Remove the secondary and primary piston assemblies.
  2.  



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Fig. Fig. 8: Carefully pull the piston assemblies out of the master cylinder bore

  1. Remove the screw from the secondary piston assembly; remove the spring.
  2.  



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Fig. Fig. 9: Remove the screw from the secondary piston assembly

  1. Clean all parts thoroughly with clean brake fluid only. Any other cleaner may damage components.
  2.  



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

To install:
  1. Lubricate the new piston assemblies with clean, fresh brake fluid. Install them in the cylinder bore. Installation is easier if the pistons are rotated during insertion.
  2.  



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Fig. Fig. 11: Lubricate the new piston assemblies with clean, fresh brake fluid

  1. Stand the cylinder on the shaft and press downward on the cylinder; install the stop bolt with a new metal gasket.
  2.  
  3. Invert the cylinder so that the shaft is now up. Press down on the shaft and install the inner snapring.
  4.  
  5. Install the secondary cups, bushing and the outer snapring.
  6.  
  7. Install the seal on the master cylinder mounting flange.
  8.  

1990-95 Models

Disassembly of the master cylinder is not recommended by the manufacturer. If an internal problem is suspected, the unit must be replaced.

 
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