The retaining clip is the most overlooked part of the braking system. It's also one of the most critical—especially in the automotive aftermarket, where the variety of applications and operating requirements makes selecting the right coating essential.
What is the retaining clip and why is it critical?
The retaining clip is the component responsible for keeping the brake pad firmly positioned within the braking system. Its function seems simple. The consequences when it fails are not.
A clip that fractures in service can cause the brake pad to detach during braking. That's not a surface quality issue—it's a direct risk to the safety of the driver and the vehicle.
To fulfill its function, the clip must be manufactured from high-hardness steel. And that's where the problem begins.
The problem: hydrogen embrittlement in high-hardness parts
High-hardness steels are especially susceptible to a phenomenon known as hydrogen embrittlement.
When a high-hardness part is subjected to a conventional electrolytic zinc plating process, the hydrogen generated during electrodeposition penetrates the steel's microstructure. This creates internal stresses and microcracks that are not visible to the naked eye.
The problem doesn't end there. These fractures don't necessarily occur during the manufacturing process—they can manifest days or weeks later, under sustained load, in real operating conditions. This is known as delayed fracture.
Many manufacturers apply a dehydrogenation treatment after zinc plating to try to reverse this effect. But this treatment is not always sufficient. In parts with complex geometries, such as retaining clips—with tight bends, edges, and hard-to-reach areas—complete removal of hydrogen is not guaranteed.
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The combination of three factors makes it especially critical in this component:
High material hardness. The harder the steel, the more susceptible it is to hydrogen embrittlement. Retaining clips operate in the hardness range where this phenomenon is most severe.
Complex geometry. The folds, edges, and contact surfaces of the clip make it difficult to both apply the coating evenly and effectively remove hydrogen during dehydrogenation.
sustained load in service. The clip operates under constant tension within the braking system. This sustained load is precisely the condition that triggers delayed hydrogen fractures.
The three factors present at the same time, in the same component.
What should a coating for retaining clips have?
To properly protect a retaining clip without compromising its mechanical integrity, the coating must meet three conditions:
Non-electrolytic process. It eliminates the possibility of introducing hydrogen into the steel from the very beginning. There is no risk to manage because the risk never exists.
Acid-free pretreatment. The acids used in surface preparation for conventional processes can also introduce hydrogen before coating. An acid-free pretreatment protects the steel's microstructure from the very first stage of the process.
Uniform coverage in complex geometries. The coating must evenly cover folds, edges, and hard-to-reach areas — the same areas where hydrogen tends to concentrate and where the risk of fracture is greatest.
Laurentcoat®, the zinc-laminated coating developed and applied by Chousa, meets all three conditions. Its dip-spin application process with thermal curing completely eliminates the risk of hydrogen embrittlement, protects the steel's microstructure from the pretreatment stage, and guarantees uniform coverage even on the most complex geometries.
Do you manufacture or specify brake pad retaining clips?
Hydrogen embrittlement is a real, silent, and preventable risk. The good news is that the problem has a solution: non-electrolytic coatings like Laurentcoat® eliminate the risk at the source, without compromising corrosion resistance or the dimensional accuracy of the parts.
Do you want to assess whether the current coating on your retaining clips poses a risk to your process?
You can contact us at info@chousa.com.ar and get in touch with our technical team.