Measuring a slack adjuster correctly is vital for ensuring proper functionality in a braking system. Follow these steps to gather the necessary measurements and identify the characteristics of your slack adjuster:
1. Count the Splines
- Locate the spline area of the slack adjuster where it connects to the camshaft.
- Carefully count the number of splines (teeth) on the camshaft opening. Common spline counts are 10, 28, or 37.
- This count helps determine compatibility with the camshaft.
2. Measure from the Center of Splines to the Center of Clevis Pin
- Position a measuring tape or ruler.
- Measure the distance between:
- The center point of the spline opening.
- The center of the clevis pin hole.
- This measurement is the arm length of your slack adjuster and is crucial for replacement or repair. Measurement A in the picture below.
- Some slack adjusters have multiple clevis pin holes to make them useful for multiple applications.
3. Measure the Spline Diameter
- Use a caliper or ruler to measure the diameter of the spline opening.
- Ensure the measurement is precise, as this ensures proper fit with the camshaft.
- Typical measurements are 1.25" and 1.5". Measurement C in the picture below.
4. Determine Whether the Slack Adjuster is Manual or Automatic
- Inspect the slack adjuster:
- Manual Slack Adjusters: Require periodic manual adjustment using a wrench.
- Automatic Slack Adjusters: Self-adjust with brake use, requiring less maintenance.
- This distinction is essential for ensuring proper adjustment and brake performance.
5. Note the Manufacturing Style
- Look closely at the design, shape, and any branding or markings on the slack adjuster.
- Compare it with reference images or manufacturing guides to identify the specific style or brand.
- This information can help you find an exact replacement or compatible model.
Additional Tips
- Always clean the slack adjuster and surrounding areas before taking measurements to improve accuracy. You also might get lucky and find a part number on your slack adjuster.
- Consult your vehicleβs manual for specific measurement tolerances and guidelines.
- If unsure, seek assistance from a professional mechanic to ensure safety and proper functionality.
By following these steps, you can confidently measure your slack adjuster and gather all the necessary details for replacement or troubleshooting.
