How much brake fluid is needed for a BMW E66?
2 Answers
The BMW E66 requires approximately 2-4 liters of brake fluid. Recommendation: Brake fluid manufacturers generally recommend replacing the brake fluid every 20,000 kilometers. If the vehicle has traveled around 40,000 kilometers during this period, it should also be replaced. This is mainly to ensure the cleanliness of the brake fluid, as moisture from the air can seep into the brake fluid reservoir through the vent hole, thereby lowering the wet boiling point of the brake fluid and affecting braking performance. Therefore, avoid leaving the brake fluid reservoir cap open for extended periods. Brake Fluid Replacement: It is best to replace the brake fluid at a 4S shop or a reputable repair shop. In the early stages of automotive development, due to immature automotive maintenance equipment, brake fluid replacement was often done by repeatedly pressing the brake pedal, which made it difficult to completely replace the brake fluid.
Last week, I just changed the brake fluid for my BMW E66, and the whole process went quite smoothly. I used Dot 4 specification and bought a 1-liter bottle, with about 0.8 liters actually replaced. The technician at the shop first drained the old fluid and air, going through each wheel's brake caliper to ensure the system was clean. I remember him reminding me not to skimp on the amount—too much fluid could cause leaks, while too little might leave air bubbles, leading to spongy brakes. This car has been running for almost ten years, and I've always followed the manual's recommendation to change the brake fluid every two years or 40,000 kilometers—safety comes first. Aged brake fluid can also corrode components, so it's best not to delay until something goes wrong. The whole thing cost a few hundred bucks, but I feel much more at ease driving now, especially when braking on the highway—the response is quick and sharp.
