Front Disc Brake Caliper
OVERVIEWThe disc brake caliper assembly used on this vehicle is a multi-piston (4) caliper. This multi-piston caliper design requires each piston of the caliper assembly be disassembled and assembled one at a time rather then doing the entire caliper at once. The service procedures which follow, list the entire disassembly and assembly of each caliper half Refer to the procedure below for which caliper half that service is being performed on.
CAUTION: Excessive vise pressure can cause distortion of the caliper mounting bosses, this can affect the alignment of the caliper assembly with the braking disc.
When clamping the disc brake caliper assembly in a vise, protective caps should be used on the jaws of the vise.
INBOARD CALIPER HALF
1. Remove the front disc brake caliper from the vehicle. See Brake Caliper, Service and Repair, Removal and Installation for the removal procedure.
2. Mount the disc brake caliper assembly in a vise, using the caliper assembly mounting bosses.
3. If the brake shoes were not removed from the caliper before removing the caliper from vehicle, remove brake shoes at this time. See Brake Pad, Service and Repair, Removal and Installation, Disc Brake Shoes (Front) for the procedure.
Interconnecting Brake Tube:
4. Remove the interconnecting brake fluid tube between the inboard and outboard caliper halves.
CAUTION: The caliper assembly used on the Viper uses ISO style fittings in the disc brake caliper assembly for the interconnecting brake tube. Do not attempt to install a double wall or any other style of flared tubing into this fitting, it will damage the caliper assembly. See Hydraulic System, Brakes Lines, Service and Repair, Service Procedures, Brake Tube Repair for a description of an ISO flare and the proper procedure to make one.
Fabricated Plug:
6. Plug the interconnecting brake tube fitting on the inboard half of the caliper assembly. This fitting needs to be plugged to remove the caliper pistons on the inboard caliper half using compressed air. A plug can be fabricated using a piece of brake line tube with an ISO style flare and tube nut.
7. Lay a shop towel over the inboard caliper half to protect the finish. Place an appropriate size tool such as the seal installer or an equivalent tool over one caliper piston and dust boot. Using a C-clamp hold the seal installer or equivalent tool in place over the top of the caliper piston. Tighten the C-clamp just enough to hold the pieces in place, DO NOT USE EXCESSIVE FORCE this could damage caliper or piston.
8. Lay a shop towel over the outboard side of the caliper and the top of the vise. This is to protect the caliper and the piston from damage when the piston is removed from the bore of the caliper.
WARNING: WHEN REMOVING THE PISTON FROM THE BORE OF THE CALIPER, DO NOT PLACE HANDS OR FINGERS INTO THE CENTER AREA OF THE CALIPER. INJURY TO THE HAND OR FINGERS WILL OCCUR WHEN THE PISTON LEAVES THE BORE OF THE CALIPER.
9. Using only a rubber tipped air nozzle, insert the tip of the air nozzle into the flex hose port on the inboard caliper half. Slowly apply just enough air pressure to slowly push the unclamped piston out of the bore of the caliper.
Removing Dust Boot From Caliper:
10. When removing the piston from the bore of the caliper the dust boot may remain in the caliper. If the dust boot does not come out with the piston, carefully pry the dust boot from the retaining groove using a small screw driver. The screw driver must be inserted between the outer edge of the dust boot and the caliper. Do not insert screw driver into the bore of the caliper to remove the seal, scoring of the bore may occur.
11. Remove the dust boot from the piston that was removed from the caliper. Thoroughly clean the piston using alcohol or other suitable solvent and wipe dry using a lint free towel. Inspect all surfaces of the piston for any signs of corrosion or scoring. If the corrosion on the piston can not be removed using the solvent or the piston is scored the piston must be replaced. Do not sand the piston to remove the corrosion or scoring.
Removing Piston Seal From Caliper Bore:
12. Remove the piston seal from the inboard caliper piston bore using a sharpened pencil, trim stick or other suitable tool. Do not use a screw driver or other metal tool for this operation, due to the possibility of scratching the bore or burring the edges of the seal groove.
CAUTION: The caliper used on the Viper does not have piston bores which can be honed. If the bore of a caliper cannot be cleaned using solvent, the caliper must be replaced.
13. Clean the bore of the caliper using alcohol or another suitable solvent saturated into a lint free towel. When thoroughly cleaned, wipe the bore of the caliper dry using a clean lint free towel. Inspect all surfaces of the caliper bore for any signs of corrosion or scoring. If the corrosion on the bore of caliper can not be removed using solvent or the bore is scored, the caliper assembly must be replaced. Do not attempt to hone the bore of the caliper to remove the corrosion or scoring.
14. Using compressed air, blow out the piston bore of the caliper to remove any particles that may be left from the cleaning procedure and to ensure the bore is dry.
Piston Seal Installed In Caliper:
15. Dip the new piston seal in fresh clean brake fluid. Position the seal into the seal groove in the piston bore of the caliper. Then using your fingers gently work piston seal into seal groove in caliper bore until the seal is properly seated.
16. Lightly coat the inside of the new dust boot with fresh clean brake fluid. Then install the new dust boot on the caliper piston. Be sure the dust boot is completely seated in the retaining groove in the caliper piston.
CAUTION: Force must be applied to the piston uniformly to avoid cocking and binding of the piston in the bore of the caliper.
17. Squarely install the piston into the top portion of caliper bore. Then using your fingers evenly apply pressure to the piston, pressing it into the bore of the caliper until it is past the piston seal and bottomed in bore.
18. Position the dust boot in the counterbore of the caliper bore. Using your fingers install the dust boot into the counterbore until it is flush with the face of the caliper surface.
19. Move C-clamp and seal installer to caliper piston which has just been reconditioned. This will hold piston in place while reconditioning remaining inboard caliper piston.
20. Repeat step 8 through Step 18 on remaining piston, in inboard half of the caliper assembly. When these steps are completed, the inboard half of the caliper assembly reconditioning is completed.
OUTBOARD CALIPER HALF
1. Lay a shop towel over the outboard caliper half to protect the finish on the caliper. Place an appropriate size tool such as the seal installer or an equivalent, over the caliper piston and dust boot which had been reconditioned. Using a C-clamp, hold the seal installer or equivalent tool in place over the top of the caliper piston. Tighten the C-clamp just enough to hold the pieces in place.
Do not use excessive force. Force could damage the caliper or piston.
2. Place a shop towel in the center area of the caliper. This is to protect the piston and the caliper from damage, when the piston is removed from the bore of the caliper.
WARNING: WHEN REMOVING THE PISTON FROM THE BORE OF THE CALIPER DO NOT PLACE HANDS OR FINGERS INTO THE CENTER AREA OF THE CALIPER. HAND INJURY WILL OCCUR WHEN THE PISTON COMES OUT OF THE BORE OF THE CALIPER.
3. Using ONLY a rubber tipped air nozzle, insert the nozzle into the port for the interconnecting brake fluid line on the end of outboard half of the caliper. Slowly apply just enough air pressure to slowly push the unclamped piston out of the bore of the caliper.
Removing Dust Boot From Caliper:
4. When removing the piston from the bore of the caliper, the dust boot may remain in the caliper. If the dust boot does not come out with the piston, carefully pry the dust boot from the counterbore of the caliper using a small screw driver. The screwdriver is to be inserted between the outer edge of the dust boot and the counter bore of the caliper. Do not insert the screw driver into the piston bore of the caliper to remove the dust boot, piston bore scoring can occur.
5. Remove the dust boot from the piston. Then clean the piston using alcohol or other suitable solvent and wipe dry. Inspect all surfaces of the piston for any signs of corrosion or scoring. If the corrosion on the piston can not be removed using the solvent or the piston is scored the piston must be replaced. The piston can not be sanded to remove any of the corrosion or scoring.
Removing Piston Seal From Caliper Bore:
6. Remove the piston seal from the outboard caliper piston bore using a sharpened pencil, trim stick or other suitable tool. Do not use a screw driver or any other metal tool for this operation, due to the possible scratching of the caliper bore or burring the edges of the seal groove.
CAUTION: The caliper used on the Viper does not have piston bores which can be honed. If a piston bore of the caliper cannot be cleaned using solvent, the caliper must be replaced.
7. Clean the bore of the caliper using alcohol or another suitable solvent saturated into a lint free towel. When thoroughly cleaned, wipe the bore of the caliper dry using a clean lint free towel. Inspect all surfaces of the caliper bore for any signs of corrosion or scoring. If the corrosion on the bore of caliper can not be removed using solvent or the bore is scored, the caliper assembly must be replaced. Do not attempt to hone the bore of the caliper to remove the corrosion or scoring.
8. Using compressed air, blow out the caliper piston bore to remove any particles that may be left from the cleaning procedure and to ensure caliper bore is dry.
Piston Seal Installed In Caliper:
9. Dip the new piston seal in fresh clean brake fluid. Position the seal into the seal groove in the piston bore of the caliper. Then using your fingers gently work piston seal into seal groove in caliper bore until the seal is properly seated.
10. Lightly coat the inside of the new dust boot with fresh clean brake fluid. Then install the new dust boot on the caliper piston. Be sure the dust boot is completely seated in the retaining groove of the piston.
CAUTION: Force must be applied to the piston uniformly to avoid cocking and binding of the piston in the bore of the caliper.
11. Squarely install the piston into the top portion of caliper bore. Then using your fingers evenly apply pressure to the piston, pressing it into the bore of the caliper until it is past the piston seal and bottomed in bore.
12. Position the dust boot in the counterbore of the caliper bore. Using your fingers install the dust boot into the counterbore until it is flush with the face of the caliper surface.
13. Move the C-clamp and seal installer to the caliper piston which has just been reconditioned. This will hold the piston in place while reconditioning the remaining inboard caliper piston.
14. Repeat steps Step 2 through Step 120n the remaining piston in the inboard half of the caliper assembly. When these steps are completed the outboard half of the caliper assembly service is completed.
15. Install the front disc brake caliper on vehicle.
16. Bleed front brake calipers. See Brake Bleeding, Service and Repairs, Service Procedures for the bleeding procedure.
17. Install the wheel and tire assemblies.
18. Tighten the wheel mounting stud nuts in proper sequence until all nuts are torqued to half specification. Then repeat the tightening sequence to the full specified torque of 122 Nm (90 ft. lbs.).
19. Lower the vehicle to the ground.
NOTE: Before moving vehicle, pump the brake pedal several times to insure the vehicle has a firm brake pedal to adequately stop vehicle.
20. Road test the vehicle and make several stops to wear off any foreign material on the brakes and to seat the brake shoe linings. See Brake Shoe Burnishing under Brake Pad, Service and Repairs, Service Procedures for the correct procedure if NEW brake shoe assemblies were installed.