Procedure notes
Checking the brake fluid in your 2021 GMC Sierra 3500 HD is easy and should be done once a month. On some GMCs, the owners manual suggests pumping the brake pedal 25 times before looking at the fluid level, be sure to check your owners manual to see if this applies to your 2021 Sierra 3500 HD. In addition to checking the brake fluid level, you want to look at the color of the brake fluid in your Sierra 3500 HD - if it is dark in color or it has been more than 2 years since you have changed it, you should consider having it changed - this will help make the internal components (which are expensive) last much longer.
If you need to add 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. 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 quickly rust out the brake lines in your Sierra 3500 HD.
查看中文对照 · Chinese translation
检查你的 2021 GMC Sierra 3500 HD 的制动液非常简单，建议每月进行一次。 在一些 GMC 车型 上，用户手册建议在检查制动液液位之前，踩踏制动踏板 25 次，但请务必查阅您的 2021 Sierra 3500 HD 用户手册，确认是否适用于您的车辆。 除了检查制动液液位外，你还需要观察Sierra 3500 HD中制动液的颜色——如果颜色发暗，或者已经超过2年未更换，建议进行更换——这将有助于延长内部组件（这些组件价格昂贵）的使用寿命。
如果你需要给 Sierra 3500 HD 添加液体，务必查阅车主手册以确认应添加的正确类型——通常为 DOT 3、DOT 4 或 DOT 5，也就是硅基制动液。 请务必丢弃使用超过一年的制动液瓶装——制动液会从空气中吸收水分，液体中的水蒸气会迅速导致Sierra 3500 HD的制动管路生锈。