Service Procedure
NOTETSB EXCLUDES THE FOLLOWING VEHICLES:
FLEX FUEL, NATURAL GAS, AND GULF COAST COUNTRIES (GCC MARKET) VEHICLES.
The following may be required to perform this procedure:
^ Rotunda Exhaust Flaring Tool Part Number 309-002 with instructions sheet
^ Rotunda Template Part Number 536270
1. Verify the rear catalyst rattle by lightly tapping the rear catalytic converter with a rubber mallet. If the rear catalyst does not rattle do not continue with this TSB.
NOTE
IF CATALYST HEAT SHIELD IS RATTLING REFER TO SECTION 309-00 OF THE WORK SHOP MANUAL (WSM).
2. If the rear catalytic converter does rattle disconnect HEGO sensor electrical connector(s).
3. Remove the HEGO sensor from the exhaust system using tool number 303-476 (T94P-9472-A) or equivalent.
4. Copy and cut out the template (Rotunda Part Number 536270) from the Rotunda exhaust flaring tool instruction sheet and tape the template to the exhaust pipe just below the downstream HEGO boss.
NOTE
THE TEMPLATE MUST BE PLACED AGAINST THE HEGO BOSS BASE NOT THE WELD.
(FIGURE 2)
5. Use a white paint pencil to mark a line around the exhaust pipe at the rear edge of the template. (Figure 2)
NOTE
IN SOME RARE CASES, THE MARK MAY OCCUR SLIGHTLY ONTO THE REAR CATALYST CAN. THIS WILL NOT AFFECT THE REPAIR BECAUSE THE EXHAUST PIPE EXTENDS INTO THE CATALYST CAN.
6. Using a reciprocating saw or equivalent tool, cut through the marked line.
NOTE
IT IS VERY IMPORTANT TO MAKE SURE THE CUT IS AS STRAIGHT ACROSS AS POSSIBLE. DO NOT USE A CUTTING TORCH.
7. Unbolt the joint of the rear catalyst from the H-pipe/Y-pipe.
8. Remove the catalyst to H-pipe/Y-pipe connection flange gasket and fasteners.
NOTE
IN SOME CASES A VEHICLE MAY BE EQUIPPED WITH AN EXHAUST VIBRATION DAMPENER THAT MUST BE REMOVED AND THEN REINSTALLED IN STEP 29 OF THE REPAIR PROCESS.
9. Clean the H-pipe/Y-pipe gasket flange surface.
10. Using a flash light inspect the inside of the light off catalyst brick by looking into the exhaust pipe. (Figure 2) If the light off catalyst brick is cracked, melted, or broken. **DO Not Proceed With This TSB.** Replace the entire converter assembly.
11. If the light off catalyst brick is in good condition install the appropriate catalytic converter kit.
12. Remove the light off catalyst from the exhaust manifold but do not discard the nuts.
13. De-burr or remove the weld from the outside and inside of the light off catalyst pipe to allow the service flange to slip over the tube and allow the flare tool to fit inside the catalyst pipe.
CAUTION
TO AVOID DAMAGE TO THE CATALYST BRICK OR CATALYST PIPE DO NOT PLACE IN A BENCH VISE DURING THE DE-BURRING PROCESS.
NOTE
ALL WELD MATERIAL SHOULD BE REMOVED FROM THE PIPE.
CAUTION
DO NOT REMOVE ANY ADDITIONAL METAL FROM THE EXHAUST PIPE.
14. Install the light off catalyst to the exhaust manifold using the old nuts and torque to 30 ft-lbs (40 N.m).
15. Install service flange on the outlet pipe of the light off catalyst with the chamfer side of the flange pointing towards the rear of the vehicle. Orient the flange so the center of the flat is lined up with the HEGO boss.
NOTE
Do not skip this step as the flange cannot be installed after flaring. (Figures 3 and 4)
16. Prior to installation of the flaring tool inspect the bolts for wear or damage and replace as required in tool instructions. (Figure 5)
17. Apply 90 weight rear axle gear lube onto cone surface of flare forming tool, washers, and the threads of the four (4) bolt threads.
18. Install Rotunda flare tool 309-002 into the light off catalyst exhaust pipe cut end. When inserting the flare tool, orient the flat of the tool to the hego boss. (Figures 5 and 6)
19. Secure the flare tool by threading the HEGO alignment pin into HEGO boss.
20. Tighten HEGO alignment pin until it seats against the HEGO boss. (Figure 7)
21. Hand tighten the four (4) bolts until the 45 degree cone face touches the inside edge of the catalyst pipe.
NOTE
ENSURE THE SERVICE FLANGE IS INSTALLED CORRECTLY. (FIGURE 6)
22. In order to prevent the flare tool cone from bottoming out against the flare base, it will be necessary to fabricate a feeler gauge using a piece of metal wire (Figures 8, 9, and 10). Use this to ensure the flare cone stops short of the base at the end of the flaring process.
CAUTION
DO NOT USE POWER/AIR TOOLS. THIS WILL DAMAGE THE FLARING TOOL!
23. Tighten the four (4) bolts a 1/4 turn at a time until a flare has been formed or the flaring cone stops short of the base. Refer to Step 22 to prevent flare tool damage. Periodically check the flare progress. If more flare is needed at one position, turn that bolt more to keep the flare as uniform as possible. Check to make sure that the service flange is not binding or interfering with the flare.
24. Once a flare has been achieved the flaring procedure is complete.
25. Remove the flaring tool.
NOTE
REMOVE BURRS OR SHARP EDGES FROM THE LIGHT OFF CATALYTIC CONVERTER FLARE OR DAMAGE TO THE GASKET MAY RESULT.
26. Remove and discard the old exhaust manifold nuts and loosely install the new exhaust manifold nuts to secure the light off catalyst to the exhaust manifold.
NOTE
DO NOT TORQUE NUTS AT THIS TIME.
27. Install new bolts and gasket onto the service flange of the light off catalyst. (Figure 11)
28. Install new rear catalyst as shown. (Figure 11)
NOTE
HAND TIGHTEN THE NUTS.
NOTE
THE HEAT SHIELD FACES THE VEHICLE UNDERBODY, THERE IS NO LOWER SHIELD BY DESIGN.
29. Connect new rear catalyst to the H-pipe/Y-pipe exhaust using the new nuts, bolts, and new gasket.
NOTE
IF AN EXHAUST VIBRATION DAMPENER WAS REMOVED IT MUST BE INSTALLED AT THIS TIME.
30. Follow bolt/nut tightening sequence A, B, C, and torque specifications. (Figure 12) It is important to follow this rear-to-front sequence to ensure proper alignment of system.
NOTE
THE COPPER GASKET WILL VISUALLY DEFORM TO PROPERLY SEAL THE JOINT.
NOTE
THE NEW CATALYST MUST BE AT LEAST 1-1/2 INCHES (38 MM) FROM THE TOP OF THE EXHAUST PIPE TO THE FRAME CROSS MEMBER.
31. Apply a thin coat of anti-seize lubricant to the threads of the HEGO, install and torque to 30 lb-ft (40 N.m) and connect the electrical connector.