Charcoal Canister

This procedure covers the removal and replacement of the evaporative emission control system charcoal canister on a 1972 Ford F-100 with 302 V8 engine.

Warnings

Tools required

Parts

• Charcoal canister × 1 — Use OEM specification
• Vapor hose clamps × 3 — 5/8" or 3/4" worm gear clamps

Preparation

1. Park vehicle on level ground and engage parking brake
2. Allow engine to cool completely if recently operated
3. Locate the charcoal canister mounted on the driver side inner fender well in the engine compartment

Procedure

1. 1

   Identify canister connections
   Locate the vapor hoses connected to the charcoal canister and note their port assignments before disconnecting. On most 1972 F-100 canisters the fuel tank vapor line, the purge line to the carburetor/intake, and a filtered air inlet at the base are present. Verify each connection against your specific canister and label the hoses for reinstallation. Note the routing of each hose for reinstallation.
2. 2

   Disconnect fuel tank vapor line
   Using pliers, compress or loosen the hose clamp on the top port vapor line. Slide the clamp back along the hose away from the canister. Twist and pull the vapor hose off the canister nipple. If the hose is stuck due to age, carefully use a flat blade screwdriver to break the seal between hose and nipple.
3. 3

   Disconnect purge line
   Compress or loosen the hose clamp on the center port purge line that runs to the carburetor. Slide the clamp back and remove the hose from the canister nipple using the same technique as the previous step.
4. 4

   Disconnect air inlet line
   Remove the filtered air inlet hose from the bottom port of the canister. This line typically has a small foam filter element at its open end. Note the orientation and routing of this line.
5. 5

   Remove canister mounting bracket
   Remove the single bolt securing the canister mounting bracket to the inner fender well. The canister is held by a metal strap-style bracket. Use a socket and ratchet to remove the mounting bolt and lift the canister free from the bracket.
6. 6

   Inspect vapor hoses
   Examine all three vapor hoses for cracks, hardening, or deterioration. The rubber hoses on 1972 models are over 50 years old and commonly require replacement. Check that hose routing does not create any kinks or sharp bends. Replace any questionable hoses before installing the new canister.
7. 7

   Install new canister in bracket
   Position the new charcoal canister into the mounting bracket with ports facing in the same orientation as the original. Install the mounting bolt and tighten securely so the bracket strap holds the canister firmly without crushing the housing. The bracket strap should hold the canister firmly without crushing the housing.
8. 8

   Connect air inlet line
   Install the filtered air inlet hose onto the bottom port of the new canister. Ensure the foam filter element is clean and properly positioned at the open end of the hose. Secure with a hose clamp positioned 1/2 inch from the end of the hose.
9. 9

   Connect purge line to carburetor port
   Install the purge line onto the center port of the canister, routing it toward the carburetor/intake manifold purge fitting as originally configured. Push the hose firmly onto the nipple until it bottoms out. Position a new or reused hose clamp 1/2 inch from the hose end and tighten securely.
10. 10

    Connect fuel tank vapor line
    Install the fuel tank vapor line onto the top port of the canister. This line runs along the frame rail from the fuel tank area. Push the hose fully onto the nipple and secure with a hose clamp positioned 1/2 inch from the hose end.

Reassembly

1. Double-check that all three vapor lines are securely connected and clamped
2. Verify the air inlet filter element is clean and unobstructed
3. Ensure no vapor hoses are kinked, pinched, or routed near hot exhaust components

Verification

• Start the engine and allow it to idle. Listen for any hissing sounds indicating vacuum leaks at hose connections
• Check that the canister is firmly mounted and does not rattle or move
• With engine at operating temperature, verify no fuel vapor odor is present around the canister area
• Rev the engine briefly and confirm the purge system is functioning by checking for smooth idle return

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