Race Car Brake Fade! What Causes It? - Tech Session

Grant Loc
July 9, 2011

Hello, how are you today?

It has been a few weeks since my last article, the reason for this has been due to being very busy supplying Motorsport parts to some of the leading race teams and developing lots of new Motorsport products for you all. Enough of all that lets get down to what you want to find out about. What is brake fade?

Brake fade is totally frightening and scary when it happens, however at some point I can guarantee you will experience it in your racing career.

After reading this article you will understand why it has happened and what it is. Normally there are two type of brake fade, boiling of the brake oil and the break down of the brake pads.

Boiling Of The Brake Fluid

This the most common brake fade, this is caused due to the brake fluid getting so hot from the friction of the brakes pads and discs being transferred into the brake fluid. This heat dissipation eventually boils the brake fluid causing air bubbles, these air bubbles that are created compress when the pedal is pressed. The solid link from the master cylinder to the caliper has been compromised with air that will compress.

Some times in extreme cases the brake pedal will go to the floor and not offer hardly and braking at all! The only way to bring the brakes back to a working system is to allow the brake fluid to cool down. This is pretty hard in a race environment when you are pushing the car to the limits. However there are techniques that can help, I will talk about these later in this article.

Overheating Of The Brake Pads

The other reason for brake fade is the brake pads getting very hot again via the heat dissipation from the friction caused when hard braking. In this scenario the brake pads will get so hot that the composite of the pads will be compromised. What happens is the pads temperature has risen past the point that the pads are designed to operate at. When this happens the gas in the pads is boiled out of them, this gas does not just evaporate away it forms a layer on the pad between the pad and the disc / rotor.

When this occurs the layer acts almost like a lubricant so the pad can not create the desired braking needed to slow the car. You will find in this situation the pedal will be as normal however it will not matter how hard you push the pedal the car will not brake as normal.

What to do when you have brake fade?

Both of these scenarios are due to heat in the brake system, the only solution is to cool the system down. As I mentioned before that is very difficult when you are in a race situation and driving the car to its limits. But with either of these brake fade circumstances you will not be able to drive the car to its limits.

There are a few ways to help cool down the brakes without affecting your speed too much.

Braking really late for corners is not a great practice, as this will cause heat problems and will not gain you very much time. Therefore, braking a little earlier will not effect you lap times a great deal, as long as you brake lightly so your corner entry speed is just as high as it would normally be.

When the braking is lighter the heat is less so your brakes will stay cooler to reduce the heat problem. The goal is to keep the heat out of the brake system and allow the brakes to cool as much as possible allowing the air to flow through the brakes.

If you have any place on the race track where you can not use the brakes and use the throttle to slow down slightly or a combination of coming off the accelerator and slightly applying the brakes will help cool the system.

I hope you have found this interesting, thank you for your time.

----------------------------------------------------
Grant Loc has been in the Motorsports market for over 15 years and the Director of obp Ltd obp Ltd has become a major player in Manufacture and Supply of Quality Race Car Products and provides most of the leading Motorsport distributors all over the World. obp manufacture Race Pedal Boxes, Hyd Handbrakes, Alloy Fuel Swirl Pots, Alloy Fuel Tanks, Alloy Dry Oil Tanks, Alloy Header Tanks, Alloy Oil Catch Tanks, Seat Brackets. http://www.obpltd.com