* Dragging Brake Shoe: The most likely culprit is a brake shoe dragging against the drum. This could be due to:
* Improper adjustment: The brake shoes might be adjusted too tightly after the cylinder replacement. They need to have the correct clearance.
* Damaged or sticking brake shoe: A warped or damaged brake shoe could be catching on the drum. Inspect the shoes carefully for wear, damage, or sticking. Check for scoring or uneven wear on the drum itself.
* Contamination: Brake fluid or grease on the shoes can cause them to stick. Make sure everything is clean.
* Sticking return spring: A weak or broken return spring on one of the brake shoes can prevent it from retracting properly.
* Cylinder installation issue: The new wheel cylinder might not be properly installed or seated correctly, causing it to push the shoes against the drum. Double check the installation process against the manufacturer's instructions.
* Low fluid level: While less likely to cause immediate heat, a low brake fluid level could contribute to a dragging brake if it leads to a partial vacuum in the system. Check and top off the fluid reservoir as needed.
* Master cylinder problem: Although less likely, a problem with the master cylinder could cause pressure to build up in the rear brakes, leading to heat build-up.
What to do:
1. Safety First: Let the drum cool completely before working on it again. A hot drum indicates significant friction and possible damage.
2. Inspect the Brake Shoes: Carefully examine the brake shoes for damage, wear, scoring, or sticking. Replace them if necessary. Make sure they are correctly seated and moving freely.
3. Check the Wheel Cylinder Installation: Ensure the wheel cylinder is correctly installed and the brake shoes are properly adjusted. Refer to a repair manual for the correct procedure.
4. Check for Contamination: Clean all brake components thoroughly with brake cleaner. Pay particular attention to the brake shoes and the wheel cylinder.
5. Check the return springs: Inspect the return springs to ensure they are properly installed and functioning. Replace if necessary.
6. Check Brake Fluid Level: Top off the master cylinder reservoir if the brake fluid is low.
7. Check for Leaks: Look for any brake fluid leaks around the wheel cylinder or other parts of the brake system.
If you've checked all of these and the problem persists, it's best to seek help from a qualified mechanic. A continuously hot brake drum can lead to serious damage and safety risks.
