* Improper Adjustment: The most common reason. The brake shoes need to be properly adjusted to the drum. If they're too tight, they'll constantly rub against the drum, generating significant heat. This is especially likely after a replacement, as the new shoes might not be seated correctly or the adjuster mechanism might be incorrectly set. This is the first thing to check.
* Drum Runout/Warping: Even a new drum can be slightly warped or out of round. This uneven contact with the shoes causes uneven braking and heat buildup in one spot. A warped drum might have been installed, or the old one might have warped the new shoes.
* Sticking Caliper (if equipped): While less likely on a drum brake system (Cirrus rear brakes are usually drums), there's a possibility of a sticking component within the wheel cylinder itself. A seized piston or other internal part prevents the shoes from fully releasing, causing drag and heat.
* Parking Brake: Is the parking brake cable properly adjusted and releasing completely? A partially engaged parking brake will cause significant heat.
* Contamination: Something (grease, oil, brake fluid) could have gotten on the brake shoes or drum during installation, reducing friction and causing heat.
* Faulty Wheel Cylinder: Though you've replaced the shoes and drum, a problem with the wheel cylinder itself (leaks, internal problems) can lead to overheating.
Troubleshooting Steps:
1. Check for proper brake shoe adjustment: This is the absolute first step. The service manual for your vehicle will explain the correct procedure. Incorrect adjustment is the most frequent cause.
2. Inspect the brake drum for runout/warping: Use a dial indicator or even a very straight edge to check for irregularities. If the drum is warped, it needs to be replaced.
3. Check for free movement of the wheel: With the parking brake OFF, try spinning the affected wheel. It should spin freely. Any resistance indicates a problem.
4. Check the parking brake: Make sure it's completely released.
5. Inspect the wheel cylinder for leaks: Look for brake fluid leaks around the wheel cylinder.
6. Check for brake fluid contamination: Look closely at the shoes and drum for any signs of grease, oil, or other contaminants.
If you're not comfortable performing these checks yourself, take the vehicle to a qualified mechanic. Ignoring a persistently hot wheel is dangerous, as it could lead to brake failure.
