Always wear safety glasses and nitrile gloves when servicing your Polaris ATV. To inspect the wheel and brake system and to perform a tire rotation on your model year 2020 and older Sportsman 450, follow these steps:
1. Take a close look at each tire.
- Verify there is sufficient tread depth. Tires should be replaced once they reach one-eighth inch or 3 millimeters of tread depth.
- Inspect for damage that may compromise the integrity of the tire.
- Next, inspect the tire pressure and verify it is set to specification. The tire pressure should be 7 psi (48.3 kPa) for all tires.
- Lastly, take a close look at how the tires are wearing. If there is irregular wear, it may be time for a rotation.
2. Remove the tires.
- Use a 14mm socket to loosen the lug nuts while the vehicle is on the ground. Do not remove.
- Safely elevate the vehicle. Reference your Owner’s Manual for proper lifting techniques.
- Remove the lug nuts and set aside.
- Then remove the wheels and set aside.
3. With the wheels removed, the brake system can now be easily inspected. Start with the front brake system.
- First inspect the fluid level and condition in the front brake reservoir, located on the left handlebar.
- Add fluid as needed by removing the two T20 TORX® fasteners. Caution: After opening a bottle of brake fluid, always discard any unused portion. Brake fluid rapidly absorbs moisture from the air, which causes the boiling temperature to drop. This can lead to early brake fade and the possibility of an accident or serious injury.
- Follow the brake line all the way to the front junction block in the center of the chassis frame through the left front wheel well.
- Continue inspecting the brake lines to both front calipers, looking for any leaks, kinks or damage. Also, ensure the brake line retainers are properly secured.
- Inspect the connections at the front brake calipers for leaks or damage.
4. Then inspect the rear brake system.
- Lift up on the rear of the seat and pull back to remove.
- Inspect the rear brake master cylinder and ensure the fluid level is between the min and max marks.
- Next follow the brake line from the rear reservoir back to the rear brake master cylinder, looking for leaks, kinks and damage.
- Also follow the rear brake line from the front junction block to the rear brake caliper, looking for leaks, kinks and damage.
- Continue following the brake lines to the rear brake caliper, ensuring the brake line retainers are properly secured.
- Inspect the connections at the rear brake caliper. If inspection reveals any concerns, DO NOT attempt to drive the vehicle. See your authorized Polaris Service Center.
- Reinstall the seat by aligning the front tabs and pushing down firmly on the rear of the seat to engage the grommet.
5. Next, take a look at the brake pads and rotors. Caution: Brake rotors can become extremely hot after operation. Allow the rotors to cool completely before performing maintenance to prevent risk of burns.
- Check the brake pad thickness using a suitable tool. Be sure to check the thickness on the inside pads as well. Replace any brake pads that are worn beyond their minimum thickness of 0.180 inches (4.6 mm).
- Use a brake rotor micrometer to measure the thickness of the brake rotors and replace if worn below the minimum thickness. Rotors should be replaced when worn to 0.140 inches (3.556 mm) in the front and 0.170" (4.318 mm) in the rear.
6. Once the brake system inspection has been completed, the tires can be rotated, if applicable, and reinstalled. Rotate the wheels as needed based on wheel configuration. Caution: Due to different configurations, some wheels may not be able to be rotated. Always pay attention to all markings and directional indicators on the tires.
- Install the wheels on the vehicle and hand tighten the lug nuts.
- Safely lower the vehicle until the tires begin to touch the ground. Reference your Owner’s Manual for proper lowering techniques.
- Torque the lug nuts to specification in a crisscross pattern. Steel wheels should be torqued to 27 ft-lbs (37 Nm). Aluminum wheels should be torqued to 30 ft-lbs (41 Nm) plus an additional quarter turn.
- Lower the vehicle completely.
For more information, see your authorized Polaris Dealer. Find a dealer near you with the Dealer Locator.
Maintenance tips, procedures and specifications can be found in your Owner's Manual.
To find diagrams and replacement part numbers, use the online parts catalog.
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