It is advisable to check the state of the brake fluid every 10,000 km. As a general rule, brake fluid should be replaced every 50,000 km (or every 2 years). Your vehicle's service manual will give you more precise information about how frequently the brake fluid should be checked and changed and what type of fluid should be used. If you find anything out of the ordinary, contact your usual garage. Checking brake fluid recommendations: as brake fluid is a hazardous fluid, we recommend you to bring the used cans to a toxic waste center for disposal. Before you begin: Refer to your service manual in order to locate the brake fluid reservoir. Its location depends on the type of car you have. The brake booster is on the driver’s side of your vehicle, usually up near the firewall. Just in front of that, sitting on and connected to the brake master cylinder, is the brake fluid reservoir, usually a plastic canister like the one shown here. Older vehicles don’t have a plastic reservoir