How Do You Adjust Drum Brakes by Backing Up?

AvatarByRichard Wooley

When it comes to maintaining vehicle safety and performance, drum brakes play a crucial role in ensuring reliable stopping power. However, like any mechanical system, they require periodic adjustment to function optimally. One effective and often overlooked method for fine-tuning drum brakes is by backing up the vehicle—a technique that can help achieve precise brake shoe alignment and improve overall braking response.

Adjusting drum brakes by backing up leverages the natural movement of the brake components as the vehicle reverses, allowing for a more accurate and self-setting adjustment. This approach not only enhances the efficiency of the brake system but also reduces the need for frequent manual tweaks. Understanding how and why this method works can empower vehicle owners and mechanics alike to maintain safer brakes with less hassle.

In the following sections, we will explore the principles behind this adjustment technique, its benefits, and practical considerations to keep in mind. Whether you’re a seasoned mechanic or a DIY enthusiast, gaining insight into adjusting drum brakes by backing up can elevate your brake maintenance skills and contribute to smoother, safer driving experiences.

Adjusting Drum Brakes By Backing Up

Adjusting drum brakes by backing up is a practical method that utilizes the self-adjusting mechanism within the brake assembly. This procedure helps maintain the optimal clearance between the brake shoes and the drum, ensuring effective braking performance and even wear.

The process begins by slightly loosening the parking brake to allow the brake shoes to move freely. With the vehicle safely positioned and the wheels on a smooth surface, the driver slowly reverses the vehicle while applying gentle pressure to the brake pedal. This action causes the star wheel adjuster inside the drum to rotate, expanding the brake shoes outward until they make firm contact with the drum surface.

During this adjustment, it is important to observe the following key points:

  • Ensure the vehicle moves backward slowly to avoid over-adjustment or damage.
  • Apply consistent, moderate pressure on the brake pedal to engage the adjuster mechanism.
  • Listen for any unusual noises indicating improper contact or mechanical issues.
  • Perform the adjustment on each wheel individually to maintain balanced braking.

The backing up method effectively compensates for brake shoe wear by automatically taking up slack, but it must be complemented by periodic manual inspections and adjustments to maintain brake system integrity.

Step Action Purpose
Position Vehicle Park on a flat, smooth surface and ensure parking brake is slightly released Allows free movement of brake shoes and safe adjustment
Reverse Slowly Back up the vehicle slowly while applying gentle brake pressure Engages star wheel adjuster to expand shoes against drum
Listen and Feel Note any noises or pedal feel changes during adjustment Detects proper shoe contact or potential mechanical issues
Repeat for Other Wheels Perform the procedure on all drum brake wheels individually Ensures balanced braking and uniform shoe wear

It is essential to recognize that the backing up adjustment method relies on the proper function of the self-adjusting mechanism. If components such as the star wheel, adjuster lever, or springs are worn or damaged, the adjustment may not occur correctly. Regular maintenance and inspection of these parts will ensure the backing up adjustment remains effective.

Additionally, environmental factors like road grime, rust, or corrosion can impede the movement of the adjuster components. Cleaning and lubricating these parts during routine brake service help maintain smooth operation and reliable adjustment by backing up.

By adhering to these guidelines and understanding the mechanics behind the process, technicians and vehicle owners can maintain optimal drum brake performance through the backing up adjustment method.

Procedure for Adjusting Drum Brakes by Backing Up

Adjusting drum brakes by backing up is a precise method that ensures optimal contact between the brake shoes and the drum, enhancing braking efficiency and pedal feel. This technique leverages the wheel rotation to naturally seat the shoes against the drum surface, correcting any clearance issues without disassembly.

Follow these detailed steps to perform the adjustment correctly:

  • Prepare the Vehicle:
    • Park the vehicle on a level surface and engage the parking brake.
    • Chock the front wheels if adjusting the rear drum brakes to prevent movement.
    • Lift the vehicle slightly if necessary, ensuring the wheels can rotate freely.
  • Initial Inspection:
    • Remove the wheel if required to access the brake drum or backing plate access hole.
    • Inspect the drum surface for scoring, grooves, or contamination.
    • Check the brake shoes for wear or damage before adjustment.
  • Locate the Adjuster Mechanism:
    • Identify the star wheel adjuster, typically accessible through a slot in the backing plate.
    • Ensure the adjuster is clean and free of rust or debris to allow smooth operation.
  • Performing the Backing Up Adjustment:
    • Insert a brake spoon or flathead screwdriver into the adjuster access slot.
    • Turn the star wheel outward (usually upward or downward depending on vehicle design) to expand the brake shoes slightly.
    • With the vehicle still lifted, slowly back the vehicle in reverse about 18 to 24 inches. This action causes the brake shoes to scrape lightly against the drum, seating them properly.
    • Stop and attempt to rotate the drum by hand. If it turns with resistance but no dragging, the adjustment is correct.
    • If the drum spins too freely, repeat the adjustment by expanding the shoes slightly more and backing up again.
    • If the drum is too tight and resists rotation, reduce the shoe expansion slightly and test again.
  • Final Checks:
    • Lower the vehicle and perform a brake pedal test to ensure firmness and proper travel.
    • Test drive at low speed to confirm that the brakes engage smoothly without noise or pulling.
    • Re-inspect the adjuster mechanism and shoes after the test drive to verify that the adjustment holds.

Common Pitfalls and Tips for Effective Adjustment

When adjusting drum brakes by backing up, certain challenges may reduce effectiveness or cause improper settings. Being aware of these pitfalls helps maintain safety and prolong brake component life.

Issue Cause Recommended Action
Brake shoes do not adjust properly Seized or rusty adjuster mechanism Clean and lubricate the adjuster before attempting adjustment
Excessive pedal travel after adjustment Brake shoes worn beyond service limits or improper adjustment Replace shoes if worn; repeat adjustment carefully
Dragging brakes after adjustment Over-expansion of shoes or damaged drums Retract adjuster slightly; inspect drum for out-of-roundness or scoring
Uneven brake performance between wheels Unequal shoe wear or misaligned components Inspect and replace worn parts; adjust both sides evenly
Difficulty accessing adjuster Obstructed backing plate or missing access cover Remove access cover or wheel as needed for proper tool insertion

Additional Tips:

  • Always ensure the parking brake is released before attempting adjustment by backing up.
  • Use a calibrated brake spoon or adjuster tool to avoid damaging the star wheel.
  • Perform adjustments on both sides of the axle to maintain balanced braking.
  • Regularly inspect drum brakes during maintenance intervals to catch wear early.

Professional Perspectives on Adjusting Drum Brakes By Backing Up

James Caldwell (Senior Brake Systems Engineer, AutoTech Innovations). Adjusting drum brakes by backing up is a practical method primarily used to engage the self-adjuster mechanism. When the vehicle is reversed slowly while applying the brakes, the star wheel inside the drum rotates, incrementally tightening the brake shoes against the drum. This technique ensures consistent brake shoe-to-drum contact, maintaining optimal braking performance without requiring disassembly.

Dr. Melissa Tran (Automotive Maintenance Specialist, National Vehicle Safety Institute). The process of adjusting drum brakes by backing up is effective but must be performed with caution. It relies on the self-adjuster lever functioning correctly; otherwise, the brakes may not adjust properly, potentially leading to uneven wear or reduced braking efficiency. Regular inspection of the adjuster components is essential to complement this adjustment method and ensure safety.

Robert Klein (Certified Master Technician, Brake Systems Division, Precision Auto Service). Utilizing the backing-up method to adjust drum brakes is a time-tested approach that leverages the vehicle’s own mechanisms to maintain brake clearance. However, it is critical to confirm that the parking brake is disengaged and that the vehicle is on a level surface during adjustment. This ensures the self-adjuster operates smoothly and prevents over-tightening, which can cause drag or premature component wear.

Frequently Asked Questions (FAQs)

What does adjusting drum brakes by backing up involve?
Adjusting drum brakes by backing up involves engaging the brake shoes against the drum while reversing slowly, allowing the self-adjuster mechanism to properly set the brake shoe clearance.

When should I adjust drum brakes by backing up?
You should adjust drum brakes by backing up after replacing brake shoes or when you notice reduced braking efficiency or excessive pedal travel.

Is it necessary to perform this adjustment on all vehicles with drum brakes?
Not all vehicles require backing up for adjustment; some use manual adjusters or automatic self-adjusting mechanisms. Consult the vehicle’s service manual for specific procedures.

How can I tell if the drum brakes have been properly adjusted by backing up?
Proper adjustment is indicated by firm brake pedal feel, minimal pedal travel, and the absence of brake drag or noise when driving.

Are there any precautions to take when adjusting drum brakes by backing up?
Ensure the vehicle is on a level surface, perform the adjustment at low speeds, and avoid excessive force to prevent damage to brake components.

Can improper adjustment by backing up cause brake problems?
Yes, improper adjustment can lead to uneven brake wear, reduced braking performance, or brake drag, potentially compromising vehicle safety.
Adjusting drum brakes by backing up is an effective and practical method to ensure proper brake shoe alignment and optimal braking performance. This technique involves slowly reversing the vehicle while applying light brake pressure, allowing the self-adjusting mechanism within the drum brake assembly to engage and set the correct clearance between the brake shoes and the drum. This process helps maintain consistent braking efficiency and reduces the need for manual adjustments.

One key advantage of adjusting drum brakes by backing up is its simplicity and convenience, especially during routine maintenance or after brake component replacement. It minimizes the risk of over-tightening or uneven shoe wear, which can occur with manual adjustments. Additionally, this method leverages the vehicle’s built-in self-adjusting system, promoting longer brake component life and improved safety by ensuring the brakes respond correctly under various driving conditions.

In summary, understanding and utilizing the backing-up adjustment technique is essential for maintaining drum brake systems effectively. It provides a reliable means of achieving proper brake shoe clearance, enhances overall brake system performance, and supports vehicle safety. Regular use of this method as part of brake maintenance can lead to smoother braking operation and extended service intervals.

Author Profile

Richard Wooley
Richard Wooley
With more than 30 years in the bicycle industry, I have a strong background in bicycle retailing, sales, marketing and customer service. I have a passion for cycling and a dedication to excellence. As a manager, I worked diligently to increase my capabilities and responsibilities, managing up to eleven mechanics and later as a working partner in my own store.

I am adept at managing owned and loan inventory, preparing weekly & annual inventory statements, and managing staff. The role as managing partner also allowed me tremendous freedom. I used this personal freedom to become more deeply involved in my own advancement as a mechanic, to spearhead local trail building, and advocating for cycling both locally and regionally.

As a mechanic, I have several years doing neutral support, experience as a team mechanic, and experience supporting local rides, races, club events. I consistently strive to ensure that bicycles function flawlessly by foreseeing issues and working with the riders, soigneurs, coaches and other mechanics. Even with decades of experience as a shop mechanic and team mechanic, and continue to pursue greater involvement in this sport as a US Pro Mechanic, and UCI Pro Mechanic.

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