| [Click on images for enlarged view]
Setting up the Analyzer |
| | 1. Back-off the slack adjuster until brake shoe rollers are seated in the S-Cam lands. (Consult the service manual for each brand of auto slack adjuster for adjusting procedure) |
| | 2. Loosen the tension nut on the FBA tool to allow the arrow to swing freely.
• Set the magnet against the splined end of the S Cam.
• Rotate the stainless degree wheel to align "0" degrees in the view hole in the loose pointer.
• Gravity will help you find dead center bottom. |
| | 3. Adjust the slack adjuster until brake linings contact the brake drum.
Note and record the degrees of S-Cam rotation identified through the view window of the (loose) pointer |
| Measurements with the Analyzer |
| | A. Degrees of Rotation
• Use an accurate measuring instrument to measure brake lining thickness.
• Note the measurement
• Rotate the Lining (middle) disc so the measurement appears in the pointer window
All brake lining thickness measurements on the disc have an associated value beside them. That value is the number of Degrees of Rotation that is used up due to brake lining wear! |
| | B. Brake Drum Wear (and initial brake lining to brake drum clearance)
• Review the measurements that are now recorded on the FBA tool.
• Total degrees of S-Cam rotation; subtract the Degree value of the lining thickness.
The remaining degrees of rotation represent Brake Drum Wear and initial brake lining to brake drum clearance. |
| Oversize or Wear of the Brake Drum |
| | • Rotate the drum wear disc to align with the pointer window to reflect the remaining degree value
• The remaining degree value has a drum wear value associated with it. That value will be the Oversize or Wear of the Brake Drum. Back-off the brake adjusters to normal running clearance if rotation test is proven to be less than 120 degrees. |
| Remember: Any brake that tests BEYOND 120 degrees of rotation is Out-of-Service! |
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