Polaris RZR XP TURBO S 2019 Owner's Manual For Maintenance And Safety page 168

MAINTENANCE
BRAKES
WARNING
Operating the vehicle with a spongy brake pedal can result in loss of braking,
which could cause an accident resulting in severe injury or death. Never
operate the vehicle with a spongy-feeling brake pedal.
The front and rear brakes are hydraulic disc type brakes activated by the brake
pedal.
Always check brake pedal travel and the brake fluid reservoir level before each
use of the vehicle. When applied, the brake pedal should feel firm. Any
sponginess would indicate a possible fluid leak or low brake fluid level, which
must be corrected before riding. See the Brake Fluid section for further details.
If you discover any irregularities in brake system operation, including excessive
pedal travel, contact your dealer for proper diagnosis and repairs.
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