Chevrolet 2011 Volt Owner's Manual page 393

Check brake fluid by looking at the
brake fluid reservoir. See
.
With the vehicle not running for at
least one minute, the maximum fluid
level (A) is at the top of the reservoir
body. With the vehicle running, the
fluid level should be in the proper
operating range (B) between the
MIN and MAX marks. 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, with the vehicle running, is
in the proper operating range (B)
between the MIN and MAX marks.
Use only new DOT 3 brake
fluid from a sealed container.
See
Always clean the brake fluid
reservoir cap and the area
around the cap before removing it.
This helps keep dirt from entering
the reservoir.
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.
.