Identifying Brake Noise


Possible Causes

Brake noise is the result of the linings and drum/rotor interacting with a given variable in the friction forces between these elements. This creates axial vibrations of the drum/rotor and component parts.

The following is a list of the most common specific causes of brake noise:

  1. Poor lining-to-drum contact
  2. Imbalanced braking condition
  3. Type and condition of the suspension system
  4. Brake drum design and weight:
    1. Changing weight by machining on lathe
    2. Machining with pointed tool
  5. The condition of the brake component parts
  6. The brake design
  7. High friction materials used in light-duty applications
  8. Linings contaminated with oil
  9. Over-adjustment of component parts
    1. Linings dragging against broken surface of drums
  10. S-cams rotating reverse of wheel rotation
  11. Shoes and lining rubbing drum wall
    1. Return springs – broken, stretched or missing
    2. Worn anchor pin
    3. Worn anchor pin hole (shoe or spider)
    4. Bent spider
    5. Loose or bent camshaft
  12. Linings loose on shoe
  13. Camshaft bushings worn or need lubrication
  14. Flat spots on cams or rollers
  15. Brake chamber clevis pins worn or bent
  16. Push rod and slack adjuster not aligned
  17. Out of round drum
  18. Automatic slack adjusters not set up properly.
    (Note: All slack adjusters must be reset after each brake reline or new installation, following proper template. Haldex is the only slack which does not require a template because of its installation indicator on the slack).