Mazda 323/MX-3/626/MX-6/Millenia/Protégé 1990-1998 and Ford Probe 1993-1997

Wheel Cylinders

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CAUTION
Brake pads and shoes may contain asbestos, which has been determined to be a cancer causing agent. Never clean the brake surfaces with compressed air! Avoid inhaling any dust from brake surfaces! When cleaning brakes, use commercially available brake cleaning fluids.

REMOVAL & INSTALLATION



See Figures 1, 2, 3, 4, 5 and 6



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Fig. Fig. 1: Rear drum brake backing plate assembly and wheel cylinder

  1. Remove the brake drum(s) and brake shoes as previously described.
  2.  
  3. Disconnect the brake line from the back of the backing plate with a line type wrench.
  4.  
  5. Remove the wheel cylinder mounting bolt(s) and remove the wheel cylinder from the backing plate.
  6.  



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Fig. Fig. 2: Loosen the brake line fitting with a flare nut wrench ...



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Fig. Fig. 3: ... then carefully pull it away from the wheel cylinder



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Fig. Fig. 4: Remove the bolt(s) securing the cylinder to the backing plate



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Fig. Fig. 5: Inspect the threads for damage and replace if necessary



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Fig. Fig. 6: Remove the wheel cylinder and gasket from the backing plate

  1. Installation is the reverse of the removal procedure. Replace the wheel cylinder to backing plate gasket. Tighten the wheel cylinder bolt(s) to 7-9 ft. lbs. (10-13 Nm).
  2.  
  3. Bleed the brake system and check operation.
  4.  

OVERHAUL



See Figures 7 through 16

Wheel cylinder overhaul kits may be available, but often at little or no savings over a reconditioned wheel cylinder. It often makes sense with these components to substitute a new or reconditioned part instead of attempting an overhaul.

If no replacement is available, or you would prefer to overhaul your wheel cylinders, the following procedure may be used. When rebuilding and installing wheel cylinders, avoid getting any contaminants into the system. Always use clean, new, high quality brake fluid. If dirty or improper fluid has been used, it will be necessary to drain the entire system, flush the system with proper brake fluid, replace all rubber components, then refill and bleed the system.

  1. Remove the wheel cylinder from the vehicle and place on a clean workbench.
  2.  
  3. First remove and discard the old rubber boots, then withdraw the pistons. Piston cylinders are equipped with seals and a spring assembly, all located behind the pistons in the cylinder bore.
  4.  



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Fig. Fig. 7: Remove the outer boots from the wheel cylinder

  1. Remove the remaining inner components, seals and spring assembly. Compressed air may be useful in removing these components. If no compressed air is available, be VERY careful not to score the wheel cylinder bore when removing parts from it. Discard all components for which replacements were supplied in the rebuild kit.
  2.  



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Fig. Fig. 8: Compressed air can be used to remove the pistons and seals



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Fig. Fig. 9: Remove the pistons, cup seals and spring from the cylinder

  1. Wash the cylinder and metal parts in denatured alcohol or clean brake fluid.
  2.  



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Fig. Fig. 10: Use brake fluid and a soft brush to clean the pistons ...



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Fig. Fig. 11: ... and the bore of the wheel cylinder


WARNING
Never use a mineral-based solvent such as gasoline, kerosene or paint thinner for cleaning purposes. These solvents will swell rubber components and quickly deteriorate them.

  1. Allow the parts to air dry or use compressed air. Do not use rags for cleaning, since lint will remain in the cylinder bore.
  2.  
  3. Inspect the piston and replace it if it shows scratches.
  4.  



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Fig. Fig. 12: Once cleaned and inspected, the wheel cylinder is ready for assembly

  1. Lubricate the cylinder bore and seals using clean brake fluid.
  2.  
  3. Position the spring assembly.
  4.  
  5. Install the inner seals, then the pistons.
  6.  



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Fig. Fig. 13: Lubricate the cup seals with brake fluid



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Fig. Fig. 14: Install the spring, then the cup seals in the bore



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Fig. Fig. 15: Lightly lubricate the pistons, then install them

  1. Insert the new boots into the counterbores by hand. Do not lubricate the boots.
  2.  



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Fig. Fig. 16: The boots can now be installed over the wheel cylinder ends

  1. Install the wheel cylinder.
  2.  

 
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