Depending on where you are in North America, spring may have just arrived– or is still miles off, hidden behind a snowbank. Either way, since springtime is often when fleets and owner-operators take care of brake maintenance, now’s a good time to talk about how to fight rust jacking by choosing the right drum brake shoe.
Rust jacking can occur year-round, but winter’s combination of wet roads, temperature swings, and de-icing materials like salt or chemical compounds creates ideal conditions for corrosion to take hold on a brake shoe. Rust jacking occurs as rust builds up on the steel beneath the lining, exerting upward pressure on the friction material, eventually causing cracks and breakage. (Trailer brakes that sit idle for long periods are particularly susceptible, since moisture lingering beneath the brake material doesn’t get burned off during regular brake applications.)
The Right Coating and Superior Friction: A One-Two Punch
Rust jacking affects two key drum brake components – shoes and friction – so both should be optimized to resist it.
Fighting corrosion on the shoe begins with the right coating. At Bendix, we offer two high-quality options: our E-Coat2 electro-deposition paint process, which is featured on all OE shoes and reman shoes equipped with OE friction; and the newly launched PermaGuard™ coating on Bendix remanufactured brake shoes. By reformulating our coating and wash process, we improved PermaGuard’s ability to adhere to the metal shoe, and improved its resistance to rust jacking.
Rust jacking isn’t caused solely by the quality of a brake shoe’s coating, though: The right friction is an often-overlooked factor. Lower-cost friction materials tend to be manufactured from shorter fibers and have a lower flexural strength, which makes them more prone to delamination or deformation under the pressure caused by rust jacking.
While we’re on the subject, we can’t overemphasize the importance of maintaining good brake lining condition to both highway safety and regulatory compliance. Cracked or warped linings may not offer the stopping power necessary to meet federal Reduced Stopping Distance (RSD) regulations, and brake lining inspections factor significantly into Compliance, Safety, Accountability (CSA) scoring.
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