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:
- Poor lining-to-drum contact
- Imbalanced braking condition
- Type and condition of the suspension system
- Brake drum design and weight:
- Changing weight by machining on lathe
- Machining with pointed tool
- The condition of the brake component parts
- The brake design
- High friction materials used in light-duty applications
- Linings contaminated with oil
- Over-adjustment of component parts
- Linings dragging against broken surface of drums
- S-cams rotating reverse of wheel rotation
- Shoes and lining rubbing drum wall
- Return springs – broken, stretched or missing
- Worn anchor pin
- Worn anchor pin hole (shoe or spider)
- Bent spider
- Loose or bent camshaft
- Linings loose on shoe
- Camshaft bushings worn or need lubrication
- Flat spots on cams or rollers
- Brake chamber clevis pins worn or bent
- Push rod and slack adjuster not aligned
- Out of round drum
- 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).
