GMC 2007 Savana - Manual (Page 320)

So, it is not a good idea to top off your brake fluid.
Adding brake fluid will not correct a leak. If you
add fluid when your linings are worn, then you will
have too much fluid when you get new brake
linings. You should add or remove brake fluid, as
necessary, only when work is done on the
brake hydraulic system.
{ CAUTION:
If you have too much brake fluid, it can
spill on the engine and/or fuel operated
heater parts, if equipped. If your vehicle
has a diesel engine and a fuel operated
heater, see “Fuel Operated Heater (FOH)”
in the diesel engine supplement. The fluid
will burn if the engine is hot enough. You
or others could be burned, and your
vehicle could be damaged. Add brake
fluid only when work is done on the brake
hydraulic system. See “Checking Brake
Fluid” in this section.
Refer to the Maintenance Schedule to determine
when to check your brake fluid. See Scheduled
Maintenance (Gasoline Engine) on page 399.
Checking Brake Fluid
You can check the brake fluid without taking off
the cap.
Look at the brake fluid
reservoir. The fluid level
should be above
MIN. If it is not, have
your brake 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.
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