Exhaust Gasket - Rear

This procedure covers replacement of the rear exhaust gasket between the catalytic converters and the rear exhaust section on the 2011-2014 Ford F-150 5.0L V8 Coyote engine.

Warnings

Tools required

Parts

• Rear exhaust flange gasket × 1 — Use OEM specification or equivalent donut gasket
• Exhaust flange bolts and nuts (if corroded) × 1 — M10 x 1.5 exhaust hardware

Preparation

1. Park vehicle on level surface and allow exhaust system to cool completely (minimum 2 hours after last operation)
2. Chock the front wheels securely
3. Raise the rear of the vehicle using a floor jack at the rear axle or frame-mounted jacking points
4. Support vehicle with jack stands rated for the vehicle weight placed at manufacturer-specified support points
5. Spray all exhaust flange bolts and nuts with penetrating oil and allow to soak for 15-30 minutes

Procedure

1. 1

   Locate the rear exhaust connection
   Position yourself under the vehicle behind the transmission. Locate the flange connection between the catalytic converters/mid-pipe assembly and the rear muffler section. This connection is typically located near the transmission crossmember. Identify the two or three bolts securing the flange connection.
2. 2

   Support the rear exhaust section
   The rear exhaust section will drop slightly when disconnected. Have a helper support the tailpipe or use a floor jack with a block of wood to gently support the rear muffler section weight. Do not place excessive upward pressure on the exhaust.
3. 3

   Remove exhaust hanger if necessary
   If access to the flange is restricted, disconnect the nearest rubber exhaust hanger by prying the exhaust pipe loop out of the hanger bracket. Use an exhaust hanger removal tool or carefully pry with a flat bar. This will allow the exhaust to drop and provide better access to the flange bolts.
   Torque spec

   Hanger Bolts25 Nm (19 lb-ft)
4. 4

   Remove flange bolts and nuts
   Using a 15mm deep socket and ratchet, remove the flange bolts or nuts connecting the exhaust sections. There are typically 2-3 fasteners. Apply steady pressure and work slowly to avoid breaking corroded studs. If a stud begins to twist rather than the nut turning, apply more penetrating oil and attempt again. Keep track of any springs or washers present.
5. 5

   Separate the exhaust sections
   Once all fasteners are removed, carefully separate the two exhaust sections. You may need to use a pry bar to gently break the seal of the old gasket. Pull the sections apart while supporting both pieces to prevent bending. Lower the rear section slightly if needed for clearance.
6. 6

   Remove and inspect old gasket
   Remove the old gasket from between the flanges. It may be stuck to one or both flanges. Inspect both flange surfaces and the condition of the studs or bolt holes. Check for cracks, warping, or damage to the flanges that could prevent proper sealing.
7. 7

   Clean flange surfaces
   Using a wire brush, thoroughly clean both exhaust flange mating surfaces. Remove all old gasket material, carbon deposits, and rust. The surfaces must be clean and relatively flat for the new gasket to seal properly. Clean the bolt threads with the wire brush as well.
8. 8

   Install new gasket
   Position the new exhaust gasket onto the front flange (catalytic converter side). Ensure the gasket is oriented correctly and centered over the pipe opening. Some gaskets have an orientation tab or are directional.
9. 9

   Reconnect exhaust sections
   Carefully align the rear exhaust section with the front section, ensuring the gasket remains properly positioned. The bolt holes must align. You may need to adjust the rear section height or angle slightly. Have your helper support the weight or adjust the floor jack position as needed.
10. 10

    Install and hand-tighten flange bolts
    Apply anti-seize compound to the bolt threads. Install all flange bolts or nuts and hand-tighten them to hold the connection together. Do not fully tighten any fasteners yet. Ensure the gasket has not shifted out of position.
11. 11

    Torque flange bolts to specification
    Using a torque wrench, tighten the flange bolts in a cross-pattern (alternating sides) to ensure even compression of the gasket. Torque to 59 Nm (44 lb-ft). Make multiple passes, gradually increasing torque rather than going to final torque in one step.
    Torque spec

    Exhaust Flange Bolts45 Nm (33 lb-ft)
12. 12

    Reinstall exhaust hangers
    If any exhaust hangers were disconnected, reconnect them by pushing the exhaust pipe loop back into the rubber hanger mount. Ensure the exhaust system is properly aligned and supported at all hanger points with no strain on the connection.
    Torque spec

    Hanger Bolts25 Nm (19 lb-ft)

Reassembly

1. Verify all exhaust hangers are properly connected and the system hangs evenly without binding or stress points
2. Check that there is adequate clearance between the exhaust system and the chassis, fuel tank, and driveline components
3. Remove jack stands and carefully lower the vehicle to the ground

Verification

• Start the engine and allow it to idle. Listen carefully at the repair area for any exhaust leaks (hissing or ticking sounds)
• With the engine running, carefully feel around the flange connection (without touching hot components) for escaping exhaust gases
• Rev the engine slightly and verify no leaks are present under increased exhaust pressure
• Take the vehicle for a short test drive and recheck the connection for leaks after the exhaust has reached operating temperature
• After the first drive cycle, re-inspect the flange bolts to ensure they remain tight (re-torque if necessary after exhaust cools)

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