The opinions expressed herein do not necessarily reflect those of the National Street Rod Association and/or StreetScene Magazine. Rust At Work
A fter reading Safety First in the February issue, I feel I can shed some light on what caused that rodder’s brake pads to separate from their back- ing plate. I see this routinely, at least once a week, when State Safety Inspecting trailers at the marina. Boat trailers are the worst for this problem, but the same process occurs on any brake sys- tem, disc or drum, when the vehi- cles are driven infrequently. What happens is that moisture, or water in the case of boat trail- ers, wicks into the very small gaps at the edge of the pad or shoe where it meets the backing plate. If the brakes are not used often enough to create sufficient heat to evaporate 100% of this moisture
or water, rust will start to develop between the two surfaces. Since the marina I work at is on the Chesapeake Bay, which is salt water, the problem is accelerated. The industry term for this type of failure is “brake pad jacking.” The worst thing to do to a boat trailer is to wait until you get home to wash off the wheels and suspension sys- tem, then park it until the next time you go out. The washed trail- er should be towed 10 miles or so to generate enough heat in the brakes to evaporate this moisture, drastically slowing down the for- mation of rust. Most of us with older cars treat them as if they were boat trailers, except we don’t back them into the water. But we do get the car
home from an event, wash it and put it in the garage with wet brake components. Sure, we dry off the body, so it won’t water spot, but what do we do to the brakes and undercarriage to dry them off? Probably nothing. Rust is a very strong adversary and the pressure generated by the rusting metal as it expands will push (sep- arate/crack) the friction lining off the backing plate whether it is has bonded or riveted linings. Riveted linings are rarely used on boat trailers since there are only 4-8 fas- tening rivets that secure the mate- rial to the backing plate. These points will tend to slightly (micro- scopically) cause the edges of the lining material to warp up as the rivet is compressed at installation and get farther away from the backing plate which allows the moisture/water intrusion to occur faster. Bonded lining material cov- ers 100% of that same mating sur- face so it takes longer for the area to become contaminated. The pads shown in your picture with the article do appear to have some rust under the portion of the pad that separated which is what leads me to the conclusion that the prob- lem is the same as on a boat trailer. A good practice would be to remove all the wheels at least annu- ally and do a visual inspection for rust, scoring and irregular wear on all the brake friction material. Things can go wrong that the NSRA Safety Inspection team can’t find since the wheels are not removed for this type of inspection. A few signs that something in the brake system is going bad may be increased noise, vibration, pedal hardness, or increased brake pedal travel. Rusty Holcomb Southeast Safety Division Chief
82 JUNE 2025
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