why do my rear drum brakes over adjust

Understanding Why Your Rear Drum Brakes Over Adjust

Rear drum brakes are a vital component of your vehicle’s braking system, playing a significant role in ensuring your safety on the road. However, over-adjustment of these brakes can lead to a variety of problems ranging from noise and uneven wear to decreased braking efficiency. In this article, we will explore the reasons why rear drum brakes might over-adjust and the implications of this issue.

What Causes Over-Adjustment?

Over-adjustment of rear drum brakes typically occurs due to one or more underlying factors. Here are some of the most common reasons

1. Incorrect Adjustment Procedures One of the primary causes of over-adjustment is improper adjustment during routine maintenance or repair. Many vehicles have specific procedures that should be followed, including the proper tools and techniques. Failing to adhere to these guidelines can lead to excess tightening of the brake shoes against the drum.

2. Worn or Damaged Components Over time, the components of your brake system, including the drum, shoes, and adjusting mechanism, can wear down. If these components are not replaced when they show signs of wear, it can lead to irregularities in brake performance, including over-adjustment. For instance, if the brake shoes wear unevenly, it may require more adjustment, causing the system to overcompensate.

3. Faulty Self-Adjusting Mechanism Most modern drum brakes come with a self-adjusting feature designed to automatically compensate for wear. However, if this mechanism malfunctions—perhaps due to dirt, corrosion, or misalignment—it may lead to excessive adjustments. It’s crucial to ensure that these components are clean and functioning correctly.

4. Brake Pedal Misusage How you use your brake pedal can also contribute to over-adjustment. If you frequently press the pedal hard or suddenly, this high force can trigger the self-adjusting mechanism disproportionately, leading to over-tightening.

5. Frequent Brake Use In applications where brakes are used more frequently, such as in stop-and-go traffic or mountainous driving, the shoes wear down at a quicker rate. This may lead to increased adjustments being necessary, and if the system adjusts too much, it can cause over-adjustment.

Over-adjusted rear drum brakes can result in several unwanted effects, including

- Increased Brake Drag When the brake shoes are adjusted too tightly against the drum, the vehicle may experience increased drag, leading to premature wear of both the brake shoes and the drum.

- Reduced Fuel Efficiency The extra resistance caused by drag can lead to an increase in fuel consumption. You might find yourself making more frequent stops for fuel than usual.

- Braking Performance Issues Over-adjustment can lead to compromised braking efficiency. Your vehicle may feel less stable during braking, increasing the risk of accidents.

- Unusual Noises If your rear drum brakes are over-adjusted, you may hear grinding, squeaking, or other unusual noises during braking. This can signal an immediate need for inspection.

- Safety Concerns The ultimate consequence of any braking-related issue is safety. If your brakes are not functioning as intended, you may be putting yourself and others on the road at risk.

Conclusion

Understanding the factors that contribute to the over-adjustment of rear drum brakes is essential for maintaining your vehicle’s braking system. Regular maintenance, including inspections and proper adjustments, can help prevent this issue. If you suspect that your rear drum brakes are over-adjusted or experience any related symptoms, it is advisable to consult a professional mechanic. By addressing these concerns proactively, you can ensure your vehicle remains safe and reliable on the road.