GMC 2009 Sierra - Manual (Page 349)

Checking Brake Fluid
The brake fluid can be checked without taking off the
cap by looking at the brake fluid reservoir.
The fluid level should be
above MIN. If it is not,
have the brake hydraulic
system checked to
see if there is a leak.
After work is done on the brake hydraulic system,
make sure the level is above the MIN but not over
the MAX mark.
What to Add
When you do need brake fluid, use only DOT-3 brake
fluid. Use new brake fluid from a sealed container only.
See Recommended Fluids and Lubricants on page 6-12.
Always clean the brake fluid reservoir cap and the area
around the cap before removing it. This helps keep
dirt from entering the reservoir.
{ CAUTION:
With the wrong kind of fluid in the brake
hydraulic system, the brakes might not work
well. This could cause a crash. Always use
the proper brake fluid.
Notice:
• Using the wrong fluid can badly damage brake
hydraulic system parts. For example, just a
few drops of mineral-based oil, such as engine
oil, in the brake hydraulic system can damage
brake hydraulic system parts so badly that they
will have to be replaced. Do not let someone
put in the wrong kind of fluid.
• If you spill brake fluid on your vehicle’s painted
surfaces, the paint finish can be damaged. Be
careful not to spill brake fluid on your vehicle.
If you do, wash it off immediately. See Washing
Your Vehicle on page 5-102.
5-37