For 1990-2009 cars

Causes | Correction
--- | ---
Restricted passage in vacuum booster | Replace the vacuum booster.
Contaminated/improper brake fluid | Flush the brake system and repair the affected brake components.
Leaking vacuum booster | Replace the vacuum booster
Damaged vacuum booster | Replace the vacuum booster
Glazed brake linings | Replace the glazed brake linings.
Restricted brake fluid passage | Locate and repair the source of the brake fluid restriction.
Brake pedal linkage interference/binding | Repair or replace the brake pedal linkage.
Sticky caliper or caliper pistons | Replace or repair the caliper.
Low engine vacuum | Diagnose the low engine vacuum condition.