Brake Pad Separation Due To Corrosion On Electric And Hybrid Vehicles

Brake Pad Separation On Electric And Hybrid Vehicles

Hybrid and electric vehicles use regenerative braking to capture energy to charge the batteries.

Hybrid vehicles have been on the roads for more than 20 years and according to vehicle registration information in the U.S., there are more than 6-million hybrids and more than a million electric vehicles in operation. The majority of them have disc brakes and some form of regenerative braking. These combined factors can lead to a safety issue for these vehicles.

Hybrid and electric vehicles use regenerative braking to capture energy to charge the batteries. Most of the braking force is produced by the generator and motor assembly and not the brake pads themselves. The hydraulic brakes are only used during low-speed braking, emergencies and situations where the regenerative braking system needs assistance.

During some drive cycles, the pads may never get up to the same temperatures as vehicles without regenerative braking. This can lead to corrosion issues with the brake pads. Since the wear rate are significantly lower, the brake pads will be on the vehicle longer.

Corrosion can affect the bond of the friction material with the steel. It can cause the friction material to detach or delaminate from the steel of the backing plate.

Many Toyota Prius, Chevy Volt and Tesla owners are experiencing the friction material delamination of the factory front and rear brake pads in as little as two years in service.

There are two ways to prevent corrosion on backing plates. The first way is to use better grades of steel alloys that contain the optimal mixture of raw components and have fewer impurities. For example, the quality of the steel and how the steel is milled can cause oxides or “mill scale” to form on the surface of the finished steel. When the brake pad backing plate is stamped, or a brake line is formed, these precursors of corrosion could be driven into the steel used for the final brake pad. These oxides are like carcinogens that start small, but can cause a tumor.

The second method to prevent corrosion is to apply an outer layer to prevent the environment from interacting with the steel and causing oxidation. The more resistant the outer layer is to heat, mechanical and chemical damage, the lower the chance of corrosion.

Galvanization is a plating process where an outer layer of zinc is applied to the backing plate by electroplating. Galvanization is performed before the friction material is attached to the backing plate. By galvanizing the surface between the backing plate and friction material, the possibility of corrosion that can cause edge lift and delamination is potentially reduced.

Look for a brake pad that has advanced corrosion treatments like galvanization for hybrid and electric vehicles. In addition, some aftermarket brake pads use a mechanical attachment to secure the friction material to the backing plates.

If you are inspecting brakes on a hybrid or electric vehicle, don’t assume rust and corrosion are normal. Take time to look at the critical areas like the brake lines and pull the caliper to look at the brake pads to make sure the corrosion has not attacked the area where the friction material attaches to the backing plate.

Courtesy of the Global Brake Safety Council.

You May Also Like

BorgWarner Signs Agreement for LFP Battery Packs

It will be the only non-OEM localized manufacturer with rights to localize LFP battery packs for commercial vehicles.

BorgWarner entered a strategic agreement with FinDreams Battery, a subsidiary of BYD Company Limited. Under this agreement, BorgWarner said it will be the only non-OEM localized manufacturer, unaffiliated with FinDreams Battery, with rights to localize LFP battery packs for commercial vehicles utilizing FinDreams Battery blade cells in Europe, the Americas, and select regions of Asia Pacific. The duration of the agreement is eight years.

CVT Transmissions

The point here is not to fear a customer complaint about a CVT transmission. 

Chassis Parts and Alignment Angles

Knowing why the adjustment is required is critical to performing the total alignment.

Threadlocking Compounds For Vehicle Corners

To get the most out of these “liquid” tools, you first need to know how they work.

Transmission Valve Body Service

Four basic items are necessary to start your own reprogramming ventures.

Other Posts

Regenerative Braking Service

Regenerative braking takes the forward motion of the vehicle and turns it into electrical energy.

REE Automotive, Knapheide Debut Full Vehicle Solution

REE’s first demo P7-C fully by-wire chassis cab has arrived in the U.S. and has completed its upfitting at Knapheide in Quincy, Illinois.

Chrysler Unveils Chrysler Halcyon Autonomous EV Concept

The automaker will launch its first battery-electric vehicle in 2025 and will feature an all-electric portfolio in 2028.

CITGO Enters EV Space with Pilot Program Launch

The CITGO location on 11 Mile Road in Michigan now offers both regular transportation fuel and EV charging stations.