Moisture on brakes causing rust on rotors

Sep 26, 2009

Q: I own a 2006 350Z Roadster, it has 32,000 km on it and Brembo brakes. I used it during the winter for a couple of weeks and then stored the car.

During a break in the weather I decided to take it for a drive. The car would not move, as if the brakes were locked.

After several attempts, the wheels began to move but only after a loud "crack" as the wheels freed. Looking at the rotors, a rusted outline of the pad could be seen on all four wheels.

I took the car to the dealer, and was advised that the brakes have a habit of collecting brake dust and adhering themselves to the rotors in the cold weather. I was not driving the car daily.

Having re-garaged my car, I moved it a few feet every day over the winter to ensure that the brakes would remain free. During the warmer weather, I washed the car and then left it in the garage.

A couple of days later I wanted to use the car, but again the brakes were seized against the rotors.

Having freed the car I again went to the dealer to check the brakes. I was again told that as I was not using the car daily the seizing occurs and this is a regular occurrence on high-end cars. I was told the rotors are fine and that the pads have at least 30 per cent or more left.

I have not heard of this happening on other high-end vehicles.

Technician Tom Zekveld replies:

Your brake pads are sticking to the rotors due to rust. This has everything to do with the composition of the brake pad material and the amount of moisture on the brakes. For example, you wash your car, park it and several days later the brakes are "stuck."

During the wash, water got onto your brake discs, as they are quite exposed through the open design wheels.

Here are my recommendations:

Brake vigorously to heat and dry your brakes just before you park the car, if you plan to have the car sit for several days.

Park your vehicle indoors in a dry environment if at all possible.

Do not leave your handbrake on when parking for prolonged periods

Have your brakes checked and serviced annually.

The severity of this problem will vary with brake systems, but no disc brake system is immune from rust if used infrequently in our climate.

Service Centre technician David Gerson is an independent garage operator.

Tony Prochilo is an automotive instructor at Centennial College, Scarborough.

Email your mechanical questions to wheels @ thestar.ca.

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