02/04/2007
Mastering Your Parking Brake: A Step-by-Step Adjustment Guide
The parking brake, often overlooked until it's needed most, is a crucial safety feature. Over time, the components that make up your parking brake system, particularly the shoes, can wear down, leading to a loss of effectiveness. This can manifest as your vehicle rolling on inclines, a common and potentially dangerous issue. Fortunately, adjusting your parking brake shoes is a manageable task for many DIY enthusiasts, and it can significantly improve your vehicle's safety and reliability. This guide will walk you through the process, ensuring your parking brake operates as intended.
Why Adjust Your Parking Brake?
The primary reason for adjusting parking brake shoes is wear. As the shoes make contact with the drum or the inner surface of the brake disc (depending on your vehicle's design), a small amount of material is shed with each application. This gradual wear means the gap between the shoe and the braking surface increases, requiring more travel of the parking brake lever or pedal to achieve the same braking force. Ignoring this can lead to the aforementioned rolling on hills, and in more severe cases, the parking brake may fail to hold the vehicle altogether.
Assessing Parking Brake Effectiveness
Before diving into adjustments, it's wise to assess the current performance of your parking brake. A common method is to check the pedal travel. With the vehicle in neutral and the parking brake released, press the parking brake pedal. Note how far you can press it before you feel significant resistance. For many vehicles, there's a specified pedal travel range. For instance, a common specification might be that the pedal should be firmly engaged by the time it's pressed about 75% of its total travel. If your pedal feels spongy, travels too far, or doesn't seem to hold the vehicle effectively on a moderate incline, an adjustment is likely needed.
Tools and Parts You'll Need
To undertake this adjustment, you'll generally require a few basic tools:
- Screwdrivers: Both flathead and Phillips head screwdrivers are often necessary for removing plugs and accessing the adjustment mechanism.
- Needle-nose pliers: Useful for manipulating small springs or clips if they are encountered.
- Torque wrench: Essential for correctly tightening wheel lug nuts after reinstallation.
- Jack and jack stands: For safely lifting and supporting the vehicle.
- Wheel chocks: To prevent the vehicle from rolling while you are working.
- New parking brake shoes (optional but recommended): If your shoes are significantly worn, it's best to replace them during this procedure.
- Brake cleaner: For cleaning components.
The Adjustment Procedure: A Detailed Walkthrough
The exact method for adjusting parking brake shoes can vary slightly between vehicle makes and models. However, the core principle involves accessing an adjustment mechanism located behind the brake rotor or drum and tightening the shoes until they lightly contact the braking surface.
Step 1: Preparation and Safety
Begin by ensuring the vehicle is parked on a level surface. Engage the parking brake momentarily, then release it. Place wheel chocks behind the front wheels to prevent any accidental movement. Loosen the lug nuts on the rear wheels before lifting the vehicle. Then, using a jack, lift the rear of the vehicle and securely support it with jack stands. Ensure the vehicle is stable before proceeding.
Step 2: Accessing the Adjustment Mechanism
For many modern vehicles, particularly those with disc brakes at the rear, the parking brake operates using a small drum mechanism integrated into the rear of the rotor. To access the adjustment star wheel (often called a spur wheel or cog), you'll need to remove the rear wheels. Once the wheels are off, locate a small rubber or plastic plug on the brake rotor's hub. Carefully pry this plug out using a screwdriver. This plug covers an access hole that allows you to reach the adjustment mechanism.
Step 3: Initial Brake Pad Adjustment (if applicable)
Some procedures recommend first pushing back the main brake pads to ensure they don't interfere with the rotor's free movement. With the parking brake released, use a screwdriver to gently push the caliper pistons back into their bores. Be mindful of the brake fluid level in the master cylinder reservoir; as you push the pistons back, the fluid level will rise. If it's close to the maximum mark, you may need to remove a small amount of fluid to prevent overflow. Check that the brake disc can now be spun by hand without any grinding or resistance from the main pads.
Step 4: Adjusting the Parking Brake Shoes
With the access hole exposed, rotate the brake rotor so that the hole is positioned conveniently, typically at the 3 o'clock or 9 o'clock position. Insert a screwdriver through the access hole and engage the teeth of the adjustment star wheel. Most adjustment mechanisms work by rotating this star wheel. You'll need to determine whether turning it clockwise or counter-clockwise tightens the shoes. Typically, turning the star wheel downwards (away from the top of the wheel) tightens the shoes. Experimentation is key here. Gently turn the star wheel while attempting to rotate the brake rotor. The goal is to tighten the shoes until the rotor can no longer be turned by hand without significant force. Once you achieve this point where the rotor is just starting to bind, you've found the tightest point. From this point, back off the adjustment approximately six clicks. This ensures that the shoes are not constantly dragging on the rotor, which can cause premature wear and reduced fuel economy.
Important Note: If you find yourself turning the star wheel a great deal without any noticeable tightening of the brake, you are likely turning it in the wrong direction. Switch to the opposite direction and try again.
Step 5: Repeat for the Other Side
Perform the same adjustment procedure on the opposite rear wheel. It's crucial for the parking brake to be balanced, so both sides should be adjusted to a similar tension.
Step 6: Reassembly and Testing
Once both sides are adjusted, reinstall the rubber or plastic plugs into the access holes. Mount the rear wheels back onto the vehicle and hand-tighten the lug nuts. Lower the vehicle back to the ground and then torque the lug nuts to the manufacturer's specifications in a star pattern. Now, it's time to test the parking brake. Get inside the vehicle. Pump the parking brake pedal several times. This action helps to seat the newly adjusted shoes and ensure the system is properly engaged. Check the parking brake lever or pedal travel again. It should feel firmer and engage within the expected range. Ensure the parking brake warning light on the dashboard illuminates when the brake is applied and extinguishes when it is released.
Step 7: Final Checks
After pumping the brake pedal a few times, re-check the master cylinder reservoir to ensure the fluid level is still within the acceptable range. Take the vehicle for a short, slow test drive. Apply the parking brake lightly at a low speed to confirm it engages and holds the vehicle. Also, ensure that when the parking brake is released, the rear wheels spin freely without any dragging or unusual noises.
When to Consider New Parking Brake Shoes
If, after performing the adjustment, you find that the parking brake still doesn't hold effectively, or if the adjustment mechanism has reached its limit (meaning you can't achieve proper tension), it's a strong indication that the parking brake shoes themselves are worn out and need replacement. Replacing the shoes involves removing the caliper and rotor, and might require additional tools and knowledge. If you're unsure, it's best to consult a professional mechanic.
Troubleshooting Common Issues
Parking brake lever/pedal feels too loose: This is the most common symptom of needing an adjustment. Follow the steps above to tighten the shoes.
Parking brake drags or causes noise: This usually means the shoes are adjusted too tight. Back off the adjustment mechanism a few clicks on both sides.
Parking brake doesn't hold on hills: Could be worn shoes, a stretched cable, or improperly adjusted shoes. Start with the adjustment.
Parking brake warning light stays on: Check the switch at the base of the pedal. It might be stuck or misaligned. Also, ensure the parking brake mechanism isn't over-adjusted, which can sometimes trigger the sensor.
Complementary Modifications
While you have the rear wheels off and are working on the braking system, it's an excellent opportunity to inspect and potentially replace your rear brake pads and rotors. If your parking brake shoes are worn, it's likely that your main brake components are also showing signs of wear. Performing these tasks concurrently can save you time and labour in the long run.
Frequently Asked Questions
Q1: How often should I check my parking brake?
A1: It's a good practice to check your parking brake's effectiveness at least once a year or every 12,000 miles, and more frequently if you notice any signs of reduced performance.
Q2: Can I adjust my parking brake without removing the wheels?
A2: On most vehicles with integrated drum-in-hat parking brakes, you need to remove the wheels to access the adjustment hole in the rotor. Some older vehicles with traditional drum brakes might have an adjustment access slot on the brake backing plate, allowing adjustment without wheel removal.
Q3: What happens if I overtighten the parking brake shoes?
A3: Overtightening can cause the parking brake shoes to constantly drag against the rotor. This leads to excessive heat buildup, premature wear of the shoes and rotor, reduced fuel efficiency, and can even damage other braking components.
Q4: Do I need to bleed the brakes after adjusting the parking brake?
A4: No, adjusting the parking brake shoes does not involve the hydraulic brake system, so bleeding the brakes is not necessary.
Q5: My parking brake cable seems loose. Should I adjust that too?
A5: Parking brake cables can stretch over time and may have their own adjustment points, often near the parking brake lever inside the car or on the cable itself under the vehicle. If the shoes are properly adjusted but the pedal/lever still feels too loose, the cable may need adjustment or replacement.
Conclusion
Maintaining a properly functioning parking brake is essential for your safety and the longevity of your vehicle. By following this guide, you can effectively adjust your parking brake shoes, ensuring your vehicle remains securely parked. Remember to always prioritize safety by using proper jacking procedures and securing the vehicle.
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