Rick's Free Auto Repair Advice

New brakes smell and smoke

Should new brakes smell and smoke?

Right after getting a brake job you may notice that your brakes smell and smoke. Brake pad manufacturers refer to this as the polymerization or curing process. The heat caused by normal braking on new brake friction materials cause the pads to go through this final curing process.

Many DIYers and customers think their new brakes are burning up. brakes smell like burningNot true. The smell and smoke aren’t caused by oxidation. The brake smoke and brake smell is actually the gasses formed brakes smokeduring the curing process. It’s a completely normal process when done properly.

Why do some brake pads need a curing process?

If new brake pads are heated too quickly or beyond a certain heat level, the friction material can actually lose some strength and the off-gassing can cause brake fade. So stomping on your brakes right after a brake job should be avoided unless specifically recommended by the brake pad manufacturer. Some brake pad manufacturers do recommend braking from high speeds, but those pads are usually designed for racing. Street brake friction materials should never be broken in or cured using this process.

Brake pad break in procedure

Most brake pad manufacturers specify a break-in procedure known in the industry as “bedding or burnishing,” although a few manufacturers don’t recommend any special procedure. The bedding process does several things:

• it cures the friction material,

• it embeds friction material into the pores of the brake rotor to form a film coating of friction material,

• it smooths the rotor surface.

Since brake pads differ in their formulation and manufacturing methods, manufacturers may recommend different break in procedures for each type of brake pad. For example, a manufacturer may use a molding technique that uses less binding resins but form them at higher heat that cures them more fully in the mold. A different manufacturer’s brake pad formula may use a higher priced or special resin that creates a distinct smell during the curing process.

Typical brake pad burnishing procedures

10 to 20 gradual stops from 30 mph

10 to 20 gradual stops from 30 mph with 30-second rest time between cycles

moderate driving with no heavy braking for the first 500 miles

Most brake pad compounds will take up to 300-400 miles to fully develop an even transfer film on the rotors.”

AKEBONO procedure

400 to 500 miles of moderate driving is recommended. Avoid heavy braking.

ATE procedure

400 to 500 miles of moderate driving is recommended. Avoid heavy braking

BREMBO GRAN TURISMO procedure

Apply brakes with moderate pressure slowing from 60-mph to 30-mph. Drive one-half mile to allow brakes to cool, then repeat procedure 30 more times.

HAWK procedure

Apply moderate braking pressure 6 to 10 times from 35-mph. Then make 2 to 3 more hard stops from 40 to 45-MPH without allowing the vehicle to come to a complete stop. Park the vehicle and let the brakes cool completely.

Raybestos Procedure:

If you’re using the brakes for severe duty like police or taxi service, or before track testing, perform a more rigorous burnishing process:

• 8 moderate brake applications from 40 to 10 mph at approximately ¼-mile intervals.

• 8 somewhat harder brake applications from 60 to 10 mph at approximately ½-mile intervals.

• Drive 1.5 miles

• Allow brakes to cool at least 15 minutes either by parking the vehicle or continuing to drive at moderate speeds with minimal brake applications.

©, 2017 Rick Muscoplat

Posted on by Rick Muscoplat

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