CHEVROLET Tahoe - Manual (Page 486)

Brakes
Brake Fluid
Your brake master
cylinder reservoir is
filled with DOT-3 brake
fluid. See Engine
Compartment Overview
on page 458 for the
location of the reservoir.
There are only two reasons why the brake fluid
level in the reservoir might go down. The first
is that the brake fluid goes down to an acceptable
level during normal brake lining wear. When
new linings are put in, the fluid level goes back
up. The other reason is that fluid is leaking out of
the brake system. If it is, you should have your
brake system fixed, since a leak means that
sooner or later your brakes will not work well, or
will not work at all.
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.
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