Muffler

This procedure covers the removal and replacement of the muffler on a 1970 AMC Rebel Machine with 390ci V8 engine.

Warnings

Tools required

Parts

• Muffler × 1 — Use OEM specification or performance equivalent
• Muffler clamps × 2 — 2.5 inch exhaust clamp
• Exhaust hangers × 2 — Replace if deteriorated

Preparation

1. Park vehicle on level ground and allow exhaust system to cool completely (minimum 2 hours after engine operation)
2. Place wheel chocks behind front wheels
3. Raise rear of vehicle with floor jack at rear axle housing
4. Support vehicle securely on jack stands placed under frame rails just forward of rear axle
5. Apply penetrating oil liberally to all muffler clamp bolts and allow to soak for 15-20 minutes

Procedure

1. 1

   Locate and inspect muffler connections
   Position yourself under the vehicle and locate the muffler. The AMC Rebel Machine uses a single muffler positioned approximately centered under the vehicle. Identify the inlet connection from the intermediate pipe and the outlet connection to the tailpipe. Note the condition of clamps and hangers to determine if cutting will be necessary.
2. 2

   Support the muffler
   Position a jack stand or block of wood under the muffler to support its weight during removal. This prevents the muffler from falling suddenly when connections are released and reduces stress on remaining hangers.
3. 3

   Remove inlet connection clamp
   Locate the clamp securing the intermediate pipe to the muffler inlet. Attempt to loosen the clamp bolt using a 9/16 inch wrench. If the bolt is seized and breaks or cannot be loosened, use a reciprocating saw or hacksaw to cut through the clamp. Work carefully to avoid damaging the intermediate pipe if it will be reused.
4. 4

   Remove outlet connection clamp
   Locate the clamp securing the tailpipe to the muffler outlet. Attempt to loosen the clamp bolt using a 9/16 inch wrench. If seized, cut the clamp with a saw. The Rebel Machine typically has a single tailpipe exiting passenger side rear.
5. 5

   Disconnect exhaust hangers
   The muffler is typically supported by two rubber exhaust hangers. Use exhaust hanger pliers or carefully work the rubber hangers off their mounting hooks by twisting and pulling. If hangers are deteriorated and tear, plan to replace them during installation.
6. 6

   Separate and remove muffler
   With clamps and hangers released, twist and pull the muffler to separate it from the inlet and outlet pipes. The pipes may be corroded together requiring significant force. If pipes cannot be separated, you may need to cut the muffler pipes just before the connections. Remove the muffler from under the vehicle.
7. 7

   Clean pipe connections
   Use a wire brush to clean the outside of the intermediate pipe outlet and inside of the tailpipe inlet. Remove all rust, carbon deposits, and old gasket material. This ensures proper seal and fit with the new muffler. If pipes are severely corroded or damaged, they should be replaced.
8. 8

   Position new muffler
   Slide the new muffler inlet onto the intermediate pipe and outlet into the tailpipe. Align the muffler so it is centered under the vehicle with adequate clearance from the fuel tank, axle housing, and floor pan. The muffler should hang level without binding.
9. 9

   Install exhaust hangers
   Attach the rubber exhaust hangers to their mounting hooks on the chassis. Use exhaust hanger pliers or lubricate hangers with soapy water to ease installation. Ensure hangers are fully seated on hooks and properly support the muffler.
10. 10

    Install and tighten clamps
    Install new clamps at the inlet and outlet connections. Position clamps so they bridge the joint between pipes. Tighten clamp bolts gradually, alternating between inlet and outlet, until snug. Do not fully tighten yet. Verify all clearances are adequate and muffler alignment is correct.
11. 11

    Final tightening and inspection
    Fully tighten both clamp bolts securely. Verify the entire exhaust system has proper clearance from chassis components, fuel lines, brake lines, and the rear axle throughout its full range of suspension travel. Check that all hangers are properly seated and supporting the system.

Reassembly

1. Lower vehicle from jack stands carefully, ensuring all tools and parts are removed from under vehicle
2. Remove wheel chocks after vehicle is fully lowered

Verification

• Start engine and listen for exhaust leaks at muffler connections. A hissing sound indicates a leak requiring clamp repositioning or tightening
• With engine running, visually inspect muffler connections for escaping exhaust gases
• Allow engine to reach operating temperature and verify no contact between exhaust system and chassis components
• Test drive vehicle and listen for rattles or contact sounds that would indicate improper hanger installation or clearance issues
• After initial test drive, re-check clamp tightness as thermal cycling may require minor adjustment

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