How to Add Brake Fluid: 2021 GMC Sierra 3500 HD Denali 6.6L V8 Turbo Diesel

When you hit the brake pedal in your 2021 GMC Sierra 3500 HD it pumps brake fluid down to your brakes which increases the pressure to make your car slow down. If you don't have enough brake fluid in the brake fluid reservoir, air can get in your brake lines and your Sierra 3500 HD won't stop properly. The video above shows you how to add brake fluid to your GMC Sierra 3500 HD. If you are adding brake fluid to your Sierra 3500 HD on a regular basis, you should check for leaks (we have a video for this too!) As with most fluids in your engine, brake fluid can cause serious harm if you get it in your eyes, so be sure to wear safety glasses and gloves. Brake fluid will also make your paint peel off if you spill it on your Sierra 3500 HD, so be careful not to spill it.

When adding fluid to your Sierra 3500 HD, it is important to check your owners manual for the correct type to add - it likely be either DOT 3, DOT 4 or DOT 5, also known as silicone brake fluid. Do not shake the fluid before pouring it in your vehicle - the air bubbles will foul up your brake lines. Be sure to discard bottles of brake fluid that are over a year old - brake fluid sucks the moisture out of the air and the water vapor in the fluid can rust out your brake lines quickly. Brake fluid breaks down with use and should be changed every 2 years in your GMC Sierra 3500 HD or whenever it looks dark in color - this will make the internal brake components last longer.