Buick 1994 LeSabre Owner's Manual page 236

What to Add
When you do need brake fluid, use only DOT-3
brake
fluid
--
such as Delco Supreme 11
@
(GM Part
No.1052535). Use new brake fluid from a sealed
container only, and always clean the brake fluid
reservoir cap before removing it.
NOTICE:
Don't let someone put in the wrong kind of
fluid. For example, just a few drops of
mineral-based oil, such as engine oil, in
your brake system can damage brake
system parts so badly that they'll have to
be replaced.
Brake fluid can damage paint, so be careful
not to spill brake fluid on your vehicle. If
you do,
wash
it
off immediately. See
"Appearance Care"
in
the Index.
Brake Wear
Your Buick has front disc brakes and rear drum brakes.
Disc brake pads have built-in wear indicators that make
a high-pitched warning sound when the brake pads are
worn and new pads are needed. The sound may come
and go or be heard all the time your vehicle is moving
(except when you are pushing on the brake pedal
firmly).