Chevrolet Blazer/Jimmy 1969-1982 Repair Guide

Wheel Cylinders

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REMOVAL





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Fig. Fig. 1 To remove a wheel cylinder, raise the rear of the vehicle and support it with jackstands ...



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Fig. Fig. 2 ... then back off the adjuster, if necessary, and remove the drum



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Fig. Fig. 3 Use a flare nut wrench to disconnect the brake line from the wheel cylinder



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Fig. Fig. 4 Unbolt the wheel cylinder retaining bolts ...



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Fig. Fig. 5 ... then remove the wheel cylinder assembly



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Fig. Fig. 6 After replacing the wheel cylinder, bleed the brake system

  1. Raise and support the axle.
  2.  
  3. Remove the wheel and tire.
  4.  
  5. Back off the brake adjustment if necessary and remove the drum.
  6.  
  7. Disconnect and plug the brake line.
  8.  
  9. Remove the brake shoe pull-back springs.
  10.  
  11. Remove the screws securing the wheel cylinder to the backing plate.
  12.  
  13. Disengage the wheel cylinder pushrods from the brake shoes and remove the wheel cylinder.
  14.  

OVERHAUL





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Fig. Fig. 7 Exploded view of a typical wheel cylinder assembly used on drum brakes

As with master cylinders, overhaul kits for wheel cylinders are readily available. When rebuilding and installing wheel cylinders, avoid getting any contaminants into the system. Always install 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, refill, and bleed the system.

  1. Remove the rubber boots from the cylinder ends with pliers. Discard the boots.
  2.  
  3. Remove and discard the pistons and cups.
  4.  
  5. Wash the cylinder and metal parts in denatured alcohol or clean brake fluid.
  6.  


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.  
  5. Lubricate the cylinder bore and counterbore with clean brake fluid.
  6.  
  7. Install the rubber cups (flat side out) and then the pistons (flat side in).
  8.  
  9. Insert new boots into the counterbores by hand. Do not lubricate the boots.
  10.  

INSTALLATION



  1. Installation is the reverse of removal. Adjust the brakes and bleed the system.
  2.  


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.

 
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