CTS 2003-2005

Brake Caliper

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Overhaul



  1. Remove the rear caliper using the procedures found in this section.
  2.  
  3. With the caliper removed from the vehicle, place it on a clean work surface. Brake fluid in the caliper will tend to run out onto the work surface, where it can damage painted components. Placing some cardboard or other disposable covering on the work surface may save time at cleanup.
  4.  
  5. Perform a visual inspection. If the caliper has an obvious crack or shows signs of collision damage, it may not be reusable. Check the tapped openings where the mounting bolts thread. In some cases, the threads can be damaged from corrosion or were cross-threaded during previous brake work. Sometimes threaded inserts can be used to save a caliper, but generally, if the caliper body shows signs of abuse, it should be replaced.
  6.  


CAUTION
Do not place your fingers in front of the caliper piston in an attempt to catch or 'protect' the piston when applying compressed air. The piston come out with a surprising amount of force and can serious injure your fingers. In addition, wear eye protection because the brake fluid in the caliper will tend to spray when shop air is applied.

  1. Use clean shop cloths to pad the inside of the brake caliper during piston removal. Use just enough shop air to ease the piston out of the bore. If the piston is simply blown out, even with padding provided, it may be damaged. The piston will come out through the piston dust boot.
    1. An alternate method for piston removal on these calipers is to use a spanner-type tool (or careful work with pliers) in the slots in the end of the piston to thread the piston out of the caliper.
    2.  

  2.  
  3. Inspect the piston for scoring, nicks corrosion, and/or worn or damaged chrome plating. Replace the piston, if any of these conditions are found.
  4.  
  5. Remove the caliper boot, being careful not to scratch the housing bore. Look for a boot retaining ring. Use a small prying tool to pry up one end of the boot ring. Work the boot ring out of the caliper groove.
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WARNING
Do not use a metal tool to remove the piston seals. Metal tools may damage the caliper bores or piston seal grooves.

  1. Remove the piston seal from the groove in the caliper bore, using a small wood or plastic tool. These seals are usually "square profile" O-rings.
  2.  
  3. Remove the bleeder valve screw.
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  5. Remove the lever return spring only if replacement is required. Use a small prytool to disengage the return spring from the parking brake lever. Then unhook the spring from the stopper pin.
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  7. Remove the caliper mounting bolt (also called a 'slider pin') boots and sleeves from the caliper.
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  9. Inspect the caliper bores, pistons and mounting threads for scoring or excessive wear.
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  11. Use crocus cloth (an extremely fine abrasive cloth) to polish out light corrosion from the piston and bore. If the crocus cloth cannot remove the corrosion, do not use a more coarse abrasive. The caliper must be replaced.
  12.  
  13. Clean all parts with denatured alcohol and dry with compressed air. Inspect all parts for damage and replace as necessary.
  14.  



Click image to see an enlarged view

Fig. Exploded view of a rear disc brake caliper equipped with built-in parking brake mechanism



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Fig. Using an air gun to coax the piston from the caliper bore



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Fig. Removing the piston boot ring



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Fig. Removing/installing the parking brake lever return spring



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Fig. Cross-sectional view of the piston, showing the proper position of the dust boot on the piston

  1. Lubricate the pin sleeve with silicone grease. Install the pin bolt and pin sleeve to the caliper support. Tighten the bolt to 20 ft. lbs. (27 Nm).
  2.  
  3. Lubricate the sleeve boot with silicone grease to ease installation. Compress the lip sleeve boot and push it all the way through the caliper body until the lip emerges and seats on the inboard face of the caliper ear.
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  5. Lubricate the sleeve with silicone grease to ease assembly. Push the bolt sleeve in through the lip end of the boot until the boot seats in the sleeve groove at the other end.
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  7. Install the bolt boot onto the caliper body.
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  9. Install the pin boot over the pin sleeve (installed on the caliper support).
  10.  
  11. If removed, install a new lever return spring. Position the spring with the hook end around the stopper pin, then pry the other end of the spring over the lever.
  12.  
  13. Lightly lubricate the bleeder valve screw with anti-seize compound and install finger tight. Final tightening will be done after the system is bled.
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  15. Lubricate a new piston seal with clean brake fluid, then install the seal. Make sure the seal is not twisted.
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  17. Install the piston boot onto the piston assembly.
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  19. Lubricate the piston assembly with clean brake fluid, then install the piston and boot into the bore of the caliper body assembly. Start the piston in by hand, then thread it into the bottom of the caliper bore using a suitable spanner-type tool into the slots in the end of the piston assembly.
  20.  
  21. Install the boot ring. Make sure the outside edge of the piston boot is smoothly seated in the counterbore or the caliper body assembly. Work the boot ring into the groove near the open end of the caliper bore, being careful not to pinch the piston boot between the boot ring and the caliper body.
  22.  
  23. After installing the ring, lift the inner edge of the boot next to the piston assembly and press out any trapped air. The boot must lie flat.
  24.  
  25. Install the caliper as outlined earlier in this section. Make sure to properly bleed the brake system.
  26.  

Removal & Installation



CTS

CAUTION
Dust and dirt accumulating on brake parts during normal use may contain asbestos fibers from production or aftermarket brake linings. Breathing excessive concentrations of asbestos fibers can cause serious bodily harm. Exercise care when servicing brake parts. Do not sand or grind brake lining unless equipment used is designed to contain the dust residue. Do not clean brake parts with compressed air or by dry brushing. Cleaning should be done by dampening the brake components with a fine mist of water, then wiping the brake components clean with a dampened cloth. Dispose of cloth and all residue containing asbestos fibers in an impermeable container with the appropriate label. Follow practices prescribed by the Occupational Safety and Health Administration (OSHA) and the Environmental Protection Agency (EPA) for the handling, processing, and disposing of dust or debris that may contain asbestos fibers.

  1. Remove 2 / 3 of the brake fluid from the master cylinder.
  2.  
  3. Remove the rear wheel.
  4.  
  5. Install 2 wheel nuts to keep the rotor in place.
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  7. Using a large C-clamp against the inboard pad, compress the caliper piston into the caliper to provide clearance during removal.
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  9. Place a catch pan under the caliper.
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  11. Disconnect the brake hose from the caliper. Cap the line to prevent excessive fluid loss or contamination.
  12.  
  13. Remove the caliper mounting bolts and remove the caliper from the vehicle.
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  15. Inspect the mounting bolts; sleeves and boots for wear and/or damage. Replace parts as necessary.
  16.  

To install:

  1. Before installing the caliper, make sure the piston is fully seated in the bore and the brake pads are properly seated.
  2.  
  3. Lubricate the mounting bolt shafts and inner diameter of the sleeves with silicone grease.
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  5. Install the caliper in the caliper mounting bracket and install the mounting bolts. Torque the mounting bolts to 46 ft. lbs. (63 Nm).
  6.  
  7. Connect the brake hose with the bolt and new gaskets. Torque the brake hose bolt to 37 ft. lbs. (50 Nm).
  8.  
  9. Refill the master cylinder and bleed the brake system.
  10.  
  11. Remove the 2 wheel nuts securing the rotor.
  12.  
  13. Install the rear wheel.
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  15. Road test the vehicle for proper brake system operation.
  16.  

CTS-V

CAUTION
Dust and dirt accumulating on brake parts during normal use may contain asbestos fibers from production or aftermarket brake linings. Breathing excessive concentrations of asbestos fibers can cause serious bodily harm. Exercise care when servicing brake parts. Do not sand or grind brake lining unless equipment used is designed to contain the dust residue. Do not clean brake parts with compressed air or by dry brushing. Cleaning should be done by dampening the brake components with a fine mist of water, then wiping the brake components clean with a dampened cloth. Dispose of cloth and all residue containing asbestos fibers in an impermeable container with the appropriate label. Follow practices prescribed by the Occupational Safety and Health Administration (OSHA) and the Environmental Protection Agency (EPA) for the handling, processing, and disposing of dust or debris that may contain asbestos fibers.

  1. If the brake fluid level is midway between the maximum-full point and the minimum allowable level, no brake fluid needs to be removed from the reservoir before proceeding.
  2.  
  3. If the brake fluid level is higher than midway between the maximum-full point and the minimum allowable level, remove brake fluid to the midway point before proceeding.
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  5. Remove the front wheel.
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  7. Carefully insert a plastic flat-bladed trim tool between the rotor and inboard brake pad.
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  9. Carefully apply pressure to the inboard brake pad until both caliper inner pistons are compressed into the caliper piston bores.
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  11. Carefully insert a plastic flat-bladed trim tool between the rotor and outboard brake pad.
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  13. Carefully apply pressure to the outboard brake pad until both caliper outer pistons are compressed into the bores.
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  15. Remove the brake hose and copper gaskets from the brake caliper. Cap the line to prevent excessive fluid loss or contamination.
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  17. Remove the caliper-to-knuckle mounting bolts.
  18.  
  19. Remove the brake caliper.
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To install:

  1. Apply threadlocker to two-thirds of the threaded length of the caliper to knuckle mounting bolts.
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  3. Apply a thin coat of high temperature silicone brake lubricant to the brake caliper pin.
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  5. Install the brake caliper. Tighten the mounting bolts to 88 ft. lbs. (120 Nm).
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  7. Connect the brake hose with the bolt and new gaskets. Tighten the bolt to 25 ft. lbs. (34 Nm).
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  9. Refill the master cylinder and bleed the brake system.
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  11. Install the wheel.
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  13. Road test the vehicle for proper brake system operation.
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With Built-In Parking Brake Mechanism
  1. Using a suction gun, remove approximately 2 / 3 of the brake fluid from the master cylinder. The reason for this is that the caliper pistons must be pushed back into their bores so the caliper can be removed from the rotor. This could cause the brake fluid to overflow from the reservoir onto painted surfaces or wiring.
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  3. Raise and safely support the vehicle on safety stands.
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  5. Mark the relationship of the wheel to the hub so it can later be installed in the same relationship. This helps retain the balance of the rotating assembly.
  6.  
  7. Remove the rear tire and wheel assembly. Install two wheel lug nuts to keep the rotor on the hub.
  8.  
  9. Disconnect the brake line to the caliper. Plug the opening so all of the brake fluid does not drain from the master cylinder reservoir.
  10.  
  11. Remove the parking brake cable from the parking brake lever. Lift up on one end of the cable spring clip to free the end of the cable from the lever.
  12.  
  13. Remove the caliper slide pin bolts and carefully lift the caliper from its bracket.
  14.  

To install:

  1. Bottom the piston into the caliper bore noting the following:
    1. There is a special spanner-type tool designed to fit in the piston slots. This allows you to turn the piston and thread it into the caliper, retracting it. Use care if using a substitute tool. Careful work with suitable pliers may enable you to turn the piston back into its bore.
    2.  
    3. After bottoming the piston, lift the inner edge of the dust boot, next to the piston, and press out any trapped air. The boot must lay flat.
    4.  

  2.  
  3. Install the caliper to the mounting bracket, noting the following:
    1. If not replaced, remove the caliper mounting bolt boot from the caliper and install the small end over the tubular metal sleeve (installed on the caliper bracket). This is to prevent cutting the bolt boot when sliding the caliper body onto the sleeve.
    2.  
    3. Hold the caliper in position and start over the end of the sleeve. As the caliper approaches the boot, work the large end of the boot into the caliper groove. Then push the caliper fully onto the mounting bolt.
    4.  
    5. Pivot the caliper down, using care not to damage the piston dust boot on the inboard brake pad. Compress the mounting bolt boot by hand as the caliper moves into position to prevent boot damage.
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    7. After the caliper is in position, recheck the installation of the pad clips. If necessary, use a small flat-bladed tool to re-seat or center the pad clips on the mounting bracket.
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    9. Tighten the mounting bolts to 20 ft. lbs. (27 Nm).
    10.  

  4.  
  5. Install the cable support bracket. Connect the parking brake cable to the caliper lever. Lift up on the cable spring clip and work the end of the parking brake cable into the notch in lever.
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  7. Connect the brake fluid line. Use new copper washers, if equipped. Tighten the brake hose bolt to 32 ft. lbs. (44 Nm).
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  9. Install the tire and wheel assembly, aligning the balance marks made at removal.
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  11. Lower the vehicle.
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  13. Fill the master cylinder reservoir to the proper level using only fresh, clean DOT 3 brake fluid. Pump the brake pedal firmly to push the pistons back out into operating position and to seat the lining.
  14.  
  15. Bleed the brake system using the procedures found at the end of this section.
  16.  

Without Built-In Parking Brake Mechanism
  1. Using a suction gun, remove approximately 2 / 3 of the brake fluid from the master cylinder. The reason for this is that the caliper pistons must be pushed back into their bores so the caliper can be removed from the rotor. This could cause the brake fluid to overflow from the reservoir onto painted surfaces or wiring.
  2.  
  3. Raise and safely support the vehicle on safety stands.
  4.  
  5. Mark the relationship of the wheel to the hub so it can later be installed in the same relationship. This helps retain the balance of the rotating assembly.
  6.  
  7. Remove the rear tire and wheel assembly. Install two wheel lug nuts to keep the rotor on the hub.
  8.  
  9. Install a large C-clamp over the brake caliper and against the back of the outboard brake pad. Tighten the C-clamp until the brake caliper piston pushes into the brake caliper bore enough to slide the caliper off the rotor. Remove the C-clamp.
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  11. Disconnect the brake line to the caliper. Plug the opening so all of the brake fluid does not drain from the master cylinder reservoir.
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  13. Remove the brake caliper mounting bolts
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  15. Remove the caliper from the mounting bracket.
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To install:

  1. Install the caliper upward in position. Use care not to damage the mounting bolt boots. Lubricate the mounting bolt and boot with silicone grease. Use care to keep grease off the mounting bolt threads to avoid having the mounting bolt loosen in service. Torque the mounting bolts to 33 ft. lbs. (45 Nm).
  2.  
  3. Install the brake line to the caliper. Use new copper seal washers, if equipped. Torque the brake hose bolt to 40 ft. lbs. (54 Nm).
  4.  
  5. Install the tire and wheel assembly, aligning the balance marks made at removal.
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  7. Lower the vehicle.
  8.  
  9. Fill the master cylinder reservoir to the proper level using only fresh, clean DOT 3 brake fluid. Pump the brake pedal firmly ( 3 / 4 of a full stroke) as many times as necessary to push the piston back out into operating position, seat the linings and obtain a firm brake pedal.
  10.  
  11. Bleed the brake system using the procedures found at the end of this section.
  12.  


CAUTION
Do not move the vehicle until a firm brake pedal is obtained. Air in the brake system can cause the loss of brakes with possible personal injury.

 
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