Customer Complaint: Noise and long stops while braking.
Condition: Friction material has delaminated from the backing plate. Partial delamination at the edges or complete delamination from backing plate. The build-up of debris or surface corrosion at the join between friction material and plate can mask a delaminated edge, but any degradation of the bond will cause the NVH characteristics of the pad to change, usually resulting in noise.
• Corrosive Road De-Icing Brines: If the bonds between the friction material are weak, water, road salt and de-icing brines can work their way between the components. This can cause the friction material to separate from the backing plate as the rust penetrates the edges where the friction material meets the backing plate. The rust “jacks” the friction material and causes separation.
• Higher than normal stresses and heat: This is usually obvious on brake pads that undergo rapid heat/quench cycles. The rapid expansion and contraction of the plate can flex the plate in relation to the friction material and “break” the bond of the adhesive. Once the bond is broken, it allows the plate and friction material to resonate at different frequencies, creating noise, and typically this vibration and delamination process will continue.
Solution: Most cheap brake pads cut corners when it comes to the backing plates. It maybe a thinner gauge steel or misplaced holes that allow the pad to flex and fracture the friction material. It might also be the anti-corrosion paints or coatings needed to protect the against rust getting between the friction material and plate. Hey, you get what you pay for.
There are some premium backing plates on the market that come with premium pads. NUCAP’s NRS puts hundreds of small hooks on the plate that grab the friction material. This gets rid of the holes and the problems seen above. According to NUCAP, the hooks increase the shear strength and can prevent edge lift of the friction material. Not only can it increase overall safety, but it can decrease incidents of unwanted noise.