Think of the last time you changed the brake fluid in your car. If like most people, you can't remember, you might have the same approach towards the brake fluid in your dirt bike or ATV.
The importance of oil and filters changes in a dirt bike or ATV make it hard to forget those jobs. The ease and affordability puts lots of riders on an every other ride routine or after a certain number of hours. But brake fluid does not need changing that often and usually gets addressed once the system feels spongy or doesn't bite like it used to. By then it's too late.
How often you ride certainly impacts how often you should bleed the brakes. If you race all summer expect to bleed the brakes at least once during those warm months. If by chance you ever boil the brake fluid which happens mostly during hot temperatures combined with aggressive riding you need to flush the brakes immediately and replace with fresh fluid. But at the very least regardless of how often you ride and whether you spend time on the tracks or trails we recommend bleeding the brakes once a year.
Brake fluid tends to absorb moisture - the main reason why you should not reuse leftover brake fluid after a year. Also the reason why, after a year circulating inside the brake system, it needs changing. Keep a notebook to track fluids changes to help you remember when you need to change the brake fluid.
Brake Flush - How Often?
The once a year method generally works for the casual rider who spends a weekend or so a month riding on the trails or getting in a Moto or two at the track. Once you step up to the next level of racing or routinely heading for the trails to get in an afternoon of fun expect to bleed the brakes more often than once a year.
Front Brake Reservoir
Spongy brakes tell you right away you have surpassed the service life of the brake fluid but before reaching that point check on the condition of the fluid by looking at the site window (or site) glass on the reservoir located on the handlebars. The site window keeps you from having to open the reservoir cap to check the color of the fluid - that just invites the moisture problem.
Fresh brake fluid resembles a clear, light yellow color. The color turns cloudy and/or gets dirty with age. Once the fluid looks opaque or shows a brown tint you need to change it regardless of how well it works. Changing the brake fluid regularly ensures the integrity of the entire system preventing breakdown and premature wear on vital parts.
Site window on the rear master cylinder
Brake Fluid Change
Bleeding the brakes, flushing the brakes and changing the brake fluid pretty much all mean the same thing. You can bleed the brakes when air infiltrates the brake system to remove the air bubble but for the most part when replacing the brake fluid you bleed, flush or change.
Always use DOT 4 brake fluid for your dirt bike or ATV, DOT 3 doesn't cut it. You will also need an open ended wrench, a drip pan and a screwdriver or torx driver (depending on setup) to remove the filler cap on the reservoir.
Drainage nipple on the front brake
So, how do you flush the brakes?
Read How To Bleed Dirt Bike Brakes for a more thorough explanation but we'll give you a brief overview here to help get you started:
- Top off the reservoir
- Pump the brakes
- Loosen the drainage nipple while keeping pressure on the brake lever
- Once fluid drains, tighten the nipple and let go of the lever
- Top off brake fluid
- Repeat process
Repeat these steps until fresh fluid flows out of the drainage nipple. The old brake fluid comes out in small bursts depending on how pumped up you get the brake system. Don't forget to keep the reservoir topped off as you drain otherwise air gets into the system. Expect to use an entire bottle for the front and rear brake fluid change.
