Replacement of the CAT CGI Bellows

cen mm 49.02.000

On vehicles with CAT EPA07 compliant engines, replace the CGI bellows at the M3 maintenance interval to prevent a later failure.

Notice: A leak in the CGI piping, including the bellows, will allow unfiltered air and contaminants into the engine intake, and can cause serious engine damage.

  1. Park the vehicle, set the parking brake, chock the wheels.
  2. Open the hood.
  3. Remove the right side inner fender/splash shield as needed.
  4. Remove the CGI piping between the engine and aftertreatment device (ATD).
  5. On the workbench, remove the CGI bellows from the exhaust piping. Do not damage the piping.

    6. Note: The following step, and its substeps, is to be done without the bellows installed. This will align the pipes so that the bellows can be installed correctly.

  6. Install the CGI piping (without CGI bellows) and align piping.
    1. Attach the aft CGI pipe to the ATD.
    2. Attach the forward CGI pipe to the engine.

      Notice: When the CGI pipes and bellows are installed, there should be approximately 3/4 inch (19 mm) clearance from the main bellows. Contact between the bellows could result in an exhaust leak, which in this case may allow ingestion of contaminants into the engine causing engine damage.
      1. Use a straightedge to align the pipes so that the pipe ends that attach to the bellows are parallel and concentric.

      3. Notice: When shortening the CGI pipe(s), it is critical to leave a minimum of 1 inch (25.4 mm) of straight pipe on the end of each CGI pipe to allow for pipe insertion and clamp clearance. Failure to do this could result in an exhaust leak, which in this case may allow ingestion of contaminants into the engine causing engine damage.

    3. Once the pipes are aligned, measure the pipe gap between the CGI pipes and record the distance. See Fig., Ref. A.
      The existing pipe gap is designed at 10 inches (254 mm). A 10.75 inches (273 mm) pipe gap is required for the replacement CGI bellows and clamps. This requires one or both of the CGI pipes to be shortened.

      • Measure the pipe gap.

      1. CGI Aft Pipe

      2. CGI Forward Pipe

      Fig. 1, Measuring the Pipe Gap (typical)

    4. Using a yellow paint pen, mark the pipes 1.5 inches (38 mm) in from the end of each pipe. These two marks will be used to center the bellows between the two pipes.
    5. Once the pipes are correctly aligned and separated at the correct distance, secure the aft CGI pipe to the ATD and to any CGI pipe support brackets.
    6. Remove the forward CGI pipe from the truck.
    7. Slide the slip clamp, with the retaining ring and graphite gasket ring, on the aft CGI pipe. See Fig. for proper installation.

      1. Aft CGI Pipe

      2. Retaining Ring

      3. Graphite Gasket

      4. Slip Clamp

      5. CGI Bellows

      Fig. 2, Aft Facing Slip Clamp Installation

    8. Slide the new bellows onto the aft CGI pipe as far as it will go. See Fig. , Ref. A. Measurement A should be at least 7/16 inch (10 mm) past the face of the flange.

      • At least 7/16 inch (10 mm)

      1. Forward CGI Pipe

      2. CGI Bellows

      3. Aft CGI Pipe

      Fig. 3, CGI Bellows Installation

    9. Install the slip clamp with the retaining ring and graphite gasket ring onto the forward CGI pipe. See Fig. for proper installation.

      1. CGI Bellows

      2. Slip Clamp

      3. Retaining Ring

      4. Graphite Gasket

      5. Forward CGI Pipe

      Fig. 4, Forward Facing Slip Clamp Installation

    10. Slide the end of the forward CGI pipe into the bellows, and properly align the pipe.
    11. Secure the forward CGI pipe to the engine and any CGI pipe support brackets.
    12. Using the yellow marks, center the bellows between the exhaust pipes. Verify that the pipe is inserted at least 7/16 inch (10 mm) past the face of the flange. See Fig., Ref. A.
    13. Install the slip clamps on the bellows. Tighten the slip clamps 11 lbf·ft (15 N·m).
    14. Start the engine and check for exhaust leaks. Tighten any clamps as needed.
    Note:
    Parent topic: Exhaust
    Document Number: 0000122448
    Manual Publication Date: 2025-02-11
    Topic Publication Date: 2024-06-04