Complete replacement of the air conditioning or compressed air lines on a 1966 Chevrolet Corvette with 327ci V8, including removal of old lines, inspection of fittings, and installation of new air lines.

Warnings

Tools required

Parts

• Air line tubing (3/8" steel or copper-nickel) × 1 — Use OEM specification
• Compression fittings (3/8") × 4 — Use OEM specification
• Tube nuts × 4 — Use OEM specification
• Rubber grommets × 2 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake.
2. Raise vehicle using floor jack and support securely on jack stands at all four corners.
3. Locate the air line routing from source to destination, noting all attachment points and clips.
4. Take photographs of the existing line routing for reference during installation.
5. Clean the work area around all fittings with brake cleaner to prevent contamination.

Procedure

1. 1

   Release residual air pressure
   First confirm the line type. If this is a true compressed-air line, slowly release all air pressure at the relief valve or disconnect point and wait 2 minutes to confirm full venting. If this is an air-conditioning refrigerant (R-12) line, DO NOT vent it; the refrigerant must be recovered by a technician with EPA-approved recovery equipment before any fitting is loosened.
2. 2

   Remove line retaining clips
   Locate all retaining clips, brackets, and grommets securing the air line to the chassis and body. Remove all sheet metal screws or clips holding the line in place along its routing path (count varies by application — document the exact number and locations as you remove them). Carefully pry rubber grommets free where the line passes through body panels to prevent damage to surrounding sheet metal.
3. 3

   Disconnect upstream fitting
   Using a flare nut wrench, carefully loosen the upstream connection fitting at the air source (compressor, manifold, or tank). Hold the stationary component with a backup wrench to prevent twisting. Turn the tube nut counterclockwise while supporting the tubing to prevent bending. Completely unthread and remove the fitting.
4. 4

   Disconnect downstream fitting
   Using a flare nut wrench, loosen and remove the downstream connection fitting at the air accessory or terminus point. Again, use a backup wrench on the stationary component. Once loose, carefully pull the old air line free from both connection points.
5. 5

   Remove old air line
   Guide the old air line out of the vehicle, carefully threading it through any chassis passages, grommets, or tight routing areas. Note any specific bends or routing constraints that will need to be replicated in the new line.
6. 6

   Inspect fittings and ports
   Examine both connection ports for damage, corrosion, or thread wear. Use a wire brush to clean male pipe threads. Inspect compression seats or flare seats for cracks, scoring, or deformation. Replace any damaged fittings before proceeding.
7. 7

   Measure and cut new tubing
   Lay the old air line next to the new tubing and measure the total length required, adding 2 inches for flaring and final trimming. Use a tubing cutter to make a clean, square cut. Deburr both the inside and outside edges of the cut using a deburring tool or die grinder to prevent restriction and ensure proper flare formation.
8. 8

   Form bends in new tubing
   Using the old line as a template, carefully bend the new tubing to match the required routing. Use a tube bending tool to create smooth, gradual bends with a minimum radius of 3 inches to prevent kinking or flow restriction. Avoid sharp bends or flat spots in the tubing.
9. 9

   Create flares on tube ends
   Slide the tube nuts onto the tubing before flaring. Determine the connection style before forming ends. If the system uses 45-degree SAE flare fittings, create proper double flares on both ends per the tool manufacturer's instructions, ensuring each flare is concentric, smooth, and crack-free. If the system uses compression fittings (as listed in parts), do NOT flare the tubing — leave the cut ends square and deburred, and rely on the compression ferrule for sealing.
10. 10

    Install new air line
    Route the new air line through the vehicle following the original path documented in your photographs. Thread the line carefully through body grommets and chassis passages. Ensure adequate clearance from exhaust components (minimum 3 inches), sharp edges, and moving suspension parts.
11. 11

    Connect upstream fitting
    Thread the upstream tube nut onto the air source fitting by hand until finger-tight. Apply a small amount of pipe thread sealant to male pipe threads if applicable (not on compression or flare fittings). Using a flare nut wrench, tighten the fitting snugly while holding the stationary component with a backup wrench. Tighten until resistance is felt, then an additional 1/4 to 1/2 turn for compression-style fittings.
12. 12

    Connect downstream fitting
    Thread the downstream tube nut onto the accessory or terminus fitting by hand until finger-tight. Using a flare nut wrench and backup wrench, tighten the fitting using the same technique as the upstream connection. Do not overtighten, as this can damage the flare or crack the fitting.
13. 13

    Secure line with clips and grommets
    Install new rubber grommets where the line passes through body panels. Reinstall all retaining clips and brackets along the line routing (matching the number and locations documented during removal), ensuring the line is supported every 18 to 24 inches to prevent vibration and fatigue. Verify clearance to all moving and hot components.
14. 14

    Pressurize and leak test
    Slowly pressurize the air system to normal operating pressure. Apply a soap and water solution to all fittings and connections. Observe for bubbles indicating air leaks. If leaks are present, depressurize the system and tighten the affected fitting an additional 1/8 turn, then retest. Repeat until all connections are leak-free.

Reassembly

1. Double-check that all retaining clips are securely fastened and the line has proper support throughout its routing.
2. Verify minimum 3-inch clearance from exhaust manifolds and pipes.
3. Ensure no contact points exist between the air line and suspension components through full range of motion.
4. Lower vehicle from jack stands and remove jack.

Verification

• With the system pressurized to operating pressure, listen for any audible air leaks around fittings.
• Verify that air-powered accessories (if equipped) function properly.
• Recheck all fittings with soap solution after 24 hours of operation to confirm long-term seal integrity.
• Inspect line routing for any signs of rubbing, vibration, or contact with other components.

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