freightliner M2 Plus Maintenance Manual page 155

Exhaust
49–00 Safety Precautions
Safety Precautions in this section apply to all
procedures within this group.
DANGER
When working on the vehicle, shut down the
engine or motor, set the parking brake, and chock
the tires. Before working under the vehicle, always
place jack stands under the frame rails to ensure
the vehicle cannot drop. Failure to follow these
steps could result in serious personal injury or
death.
49–01 CAT CGI Bellows
Replacement
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).
See Fig. 1.
5. On the workbench, remove the CGI bellows from
the exhaust piping. Do not damage the piping.
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.
6.1 Attach the aft CGI pipe to the ATD.
6.2 Attach the forward CGI pipe to the
engine.
Business Class M2 Plus Maintenance Manual, 02/10/2023
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.
6.3 Use a straightedge to align the pipes so
that the pipe ends that attach to the
bellows are parallel and concentric.
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.
7. Once the pipes are aligned, measure the pipe
gap between the CGI pipes and record the
distance. See Fig. 2, 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.
8. 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.
9. 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.
10. Remove the forward CGI pipe from the truck.
11. Slide the slip clamp, with the retaining ring and
graphite gasket ring, on the aft CGI pipe. See
Fig. 3 for proper installation.
12. Slide the new bellows onto the aft CGI pipe as
far as it will go. See
A should be at least 7/16 inch (10 mm) past the
face of the flange.
49
Fig. 4, ref. A. Measurement
49/1