Hisun HS500 Owner's Manual page 109

8-6 Periodic Maintenance and Adjustment
NOTE:
Recommended brake fluld:DOT4
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Brake fluid replacement.
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When disassembling the master cylinder or caliper, replace the brake fluid. Check the brake fluid level
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and add fluid as required.
On the inner parts of the master cylinder and caliper, replace the oil seals every two years.
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Replace the brake hoses every four years, or if cracked or damaged.
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