Rick's Free Auto Repair Advice

Brake pad bedding procedure

Do you have to perform a brake pad bedding procedure?

Yes. Brake pad bedding is aa critical first step when installing new brake pads. Simply put, the brake pad bedding procedure deposits an even thin layer of brake pad material onto the face of the rotor. An Adherent style brake pad deposits a sticky layer onto the rotor. The sticky pad and the sticky layer are what stops your vehicle. As you brake, the heat breaks the bonds of the stick surface of the brake pad and sticky layer on the rotor. At the same time it also deposit a new layer of sticky material onto the face of the rotor.

Abrasive style brake pad on the other hand, stop your car by rubbing an abrasive material against the rotor. If just the brake pad were abrasive, it would quickly wear out the rotor. That’s not a good thing. So an abrasive brake pad also deposits a layer of brake pad material onto the rotor. It sticks to the rotor, but it’s not sticky like an adherent brake pad. It’s really an abrasive film rubbing against an abrasive brake pad. So it’s the abrasive material that wears, not the rotor itself (although all rotors wear and rotors used with abrasive pads wear faster).

How about that bedding layer?

As I mentioned above, the bedding procedure lays down a thin even layer of material onto the rotor. The key here is EVEN layer. Uneven deposits of brake material are the #1 cause of brake judder,  vibration and noise.

Every brake pad is made differently so there’s no “universal” brake pad bedding procedure. Follow the procedure recommended by the brake pad manufacturer, not your buddy who knows everything about cars. Bedding temperatures vary widely, from as low as 100°F to 600°F for street pads to as much as 600°F to 1,400°F for racing pads. With that kind of temperature range, getting the right bedding procedure is critical. Too little heat prevents the pad from depositing a film layer on the rotor. Overheating the brake pads during bedding ruins the pads or the rotor.

How to perform a brake pad bedding procedure

Bedding procedures heat up the brake pad to the point where they can deposit a layer of material onto the rotor. That requires accelerating to a specified speed and then stopping with the recommended force. Some brake pad manufactuers recommend coming to a complete stop while others simply want you to slow to the recommended speed.

What happens if you don’t perform the brake pad bedding procedure?

Simple: get used to hearing annoying brake noise

Why does brake pad bedding create smoke and smell?

That’s a “maturing” or curing of the resins used during the manufacturing process. A smell and some smoke are normal and will go away after a short while.

What are the signs on improper brake pad bedding?

Rotor discoloration.

Overheated rotors will have a bluish tinge and possibly a grey tint where the brake pads are touching the rotor. The grey tint is a sign that the brake pad material has built up above the rest of the film layer.

Machining is still evident.

Brake rotors are designed with a non-directional finish from the factory. During the brake pad bedding procedure, you wear away that finish.

Can you reuse old rotors with new pads?

Only if you’re using the exact same brake pad as the ones you’re removing.

How can you screw up a brake pad bedding procedure?

Not cleaning the rotors before installing. New rotors must be washing with hot soap and water. Yes, you read that correctly. If you skip the soap and water, you’ll be leaving metaling manufacturing debris on the face of the rotor and that metallic debris will embed itself into the pad.

Remove all surface rust from the rotor face and cooling vanes.

Clean and lubricate the abutment areas and caliper slide pins. Apply high temperature synthetic brake grease to the abutment and slide pins. Install new anti-rattle clips (never reuse the old ones) and noise reduction shims). Apply a light film of brake grease to the anti rattle clips and to the back of the shims.

©, 2019 Rick Muscoplat

 

Posted on by Rick Muscoplat

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