Beating Brake-Shoe Rust Jacking

September 28, 2010

Brake Shoe

Brake Shoe
Remanufactured brake-shoe assemblies were exposed in the Haldex test lab to identical salt-spray hours using the ASTM B-117-97 procedure. The shoe with an effective corrosion-resistant coating performed noticeably better.

Trucks exposed to winter deicing chemicals are prone to have rust-jacking problems with their brakes. Rust-jacking is the buildup of rust and corrosion between the brake shoe and the lining, sometimes to a thickness of 1/8 inch or more. As corrosion builds, the lining strains against the rivets securing it to the shoe, and the frequent result is fracturing of the lining material.

According to Haldex Commercial Vehicle Systems, new deicing brine solutions of calcium chloride and magnesium chloride may be applied long before an anticipated storm arrives. This practice allows the mixture to become airborne as trucks travel across treated roadways, and the chemicals subsequently cover the trucks' complete undercarriage. The potential for corrosion exists until the chemicals are flushed from the truck, says Haldex.

Truck owners can reduce the hazard of rust-jacking, says Haldex, by specifying new and relined brake shoes having corrosion-inhibiting coatings, and by frequently washing wheel ends during winter months. And, says Haldex, you can also petition state Departments of Transportation to change snow- and ice-control policies.