'97 Owner's Manual States About Brakes...
 

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Brake Booster
Check the brake booster function as follows:

1. With the engine off, press and release the brake pedal several times. When brake pedal movement (distance of travel) remains the same from one pedal application to the next, continue to next step.

2. While depressing the brake pedal, start the engine. The pedal height should drop a little.

3. With the brake pedal depressed, stop the engine. Keeping the pedal depressed for about 30 seconds, the pedal height should not change.

4. Run the engine for one minute without depressing the brake pedal, then turn it off. Depress the brake pedal several times. The pedal travel distance will decrease gradually with each depression as the vacuum is released from the booster.

Questions: What is the function of this? Is it simply for stiffer pedal feel, or a regular maintenance check that one should do to see if the brakes operate properly?

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Brake pad wear indicators
The disc brake pads on your vehicle have audible wear indicators. When a brake pad requires replacement, it will make a high pitched scraping or screeching sound when the vehicle is in motion whether or not the brake pedal is depressed. have the brakes checked as soon as possible if the wear indicator is heard.

Self-adjusting brakes
Your vehicle is equipped with self-adjusting brakes. The disc-type brakes self-adjust every time the brake pedal is applied.

Questions: Does this apply strictly to OEM pads? Has anyone with OEM pads (or after market) ever heard this wear indicator squeal? What do the breaks adjust for? I know the brake fluid level goes down as the pads wear, because the caliper pistons need to keep the pads as close to the rotors as possible, is this what the manual is talking about?

That's just a booster operability check. All aftermarket pads should have squeelers, just lets you know when they're pretty worn out. Self-adjusting is just that, keeping them constantly in position regardless of pad and rotor wear.