How you can avoid a sinus comeback.

I have been getting a few phone calls lately from readers about bad smelling brakes after a brake service was performed. Most drivers may not know much about their vehicles, but they know when something does not smell right.

The customers who typically come back to the shop are not too happy. For shops it is a difficult phenomenon to explain. Also, the smell is typically gone by the time they get back to you, if they comeback at all. You know that there is nothing wrong with the vehicle mechanically, but you still have to set the customer's concern to rest.

What Smells?
The source of the smell is typically the brake pads. Explaining what's happening is very difficult because you are treading on very complicated chemistry that is further politicized by the friction material manufacturers.

The term and concept that you want to avoid at all costs using is "burning off." This is inaccurate and may cause the customer to become alarmed. Yes, there is heat involved when the bad smell is produced, but it is not oxidation or burning.

What is really happening is polymerization, or curing. This is a chemical process where smaller units are combined into larger and more stable units. It is like making an omelet. When heat is applied to the eggs, the omelet is formed. But, in the case of the friction material, the yoke and whites are the resins that hold the pad together.

The heat of ...