How do you identify an air spring?

🔍 1. Physical Markings & Labels

  • Firestone Branding: Look for "FIRESTONE" molded into the rubber sidewall or stamped on metal pistons.
  • Part Numbers: Check for alphanumeric codes like W01-358-XXXX (example format). These are often near the bead area or on a label.
  • DOT Codes: Compliance stamps (e.g., "DOT XP") indicate certification and may include manufacturing dates (WWYY format).
  • AIRIDE™ Logo: Specific to their air suspension line, usually prominent on the bag or packaging.

⚙️ 2. Shape & Design Characteristics

Firestone air springs vary by type. Identify the design:

  • Reversible Sleeve: Cylindrical with symmetrical metal end caps (common in trucks and trailers).
  • Convoluted: Accordion-like folds, often tapered (used in lighter vehicles or auxiliary systems).
  • Tapered Sleeve: One end wider than the other, typically for precise axle control.
    Note: AIRIDE™ covers all these types under Firestone’s brand.

📏 3. Critical Measurements

Take precise dimensions (in inches/mm):

  • Installed Height: Distance between mounting plates when inflated to operational pressure.
  • Outside Diameter: Width at the widest point (e.g., top/bottom caps or mid-section).
  • Bolt Hole Patterns: Count holes, measure spacing (PCD), and diameter.
  • Stroke Length: Minimum/maximum height range under load.

⚠️ 4. Application & Compatibility

Cross-reference with:

  • Vehicle make/model/year (e.g., "FOR F-350 2015–2020").
  • OEM part numbers from service manuals.
  • Firestone’s catalog (use their online lookup tool with your measurements/vehicle details).

🛡️ 5. Safety & Compliance Checks

  • Inspect for DOT/SAE certification marks (non-compliant parts lack these).
  • Check for wear indicators: Cracks, abrasions, or deformed beads indicate replacement need.
  • Confirm pressure ratings (PSI/bar) molded into the rubber.

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