DIY: Replacing Drum Brakes – A Step-by-Step Guide

Replacing drum brakes might seem like a daunting task, but with the right tools, knowledge, and a bit of patience, it’s a project you can tackle yourself. This comprehensive guide will walk you through each step of the process, from preparation to final inspection, ensuring a safe and successful brake job. Remember, your safety is paramount. If you’re uncomfortable with any of these steps, consult a qualified mechanic.

Why Replace Drum Brakes?

Drum brakes, though older technology than disc brakes, are still common on the rear axles of many vehicles, especially smaller cars and trucks. Over time, the brake shoes wear down, the drums can become scored or warped, and the internal components can rust and seize. Ignoring these issues can lead to:

* **Reduced braking performance:** Longer stopping distances and less control.
* **Uneven braking:** Pulling to one side during braking.
* **Noise:** Squealing, grinding, or scraping sounds.
* **Brake fade:** Loss of braking power after repeated hard braking.
* **Increased risk of accidents:** Compromised braking can lead to dangerous situations.

Replacing worn drum brakes restores your vehicle’s braking performance and ensures your safety on the road.

Tools and Materials You’ll Need

Before you begin, gather all the necessary tools and materials. This will save you time and frustration during the process.

* **New drum brake shoes:** Purchase the correct shoes for your vehicle’s make, model, and year.
* **New brake drums (optional):** If your drums are scored, warped, or excessively worn, replace them.
* **New wheel cylinders (optional):** If your wheel cylinders are leaking or corroded, replace them.
* **New hardware kit:** This includes springs, clips, and retainers. It’s often a good idea to replace these as they can weaken over time.
* **Brake cleaner:** To clean brake components.
* **Brake lubricant:** Specifically designed for brake systems (e.g., silicone-based grease).
* **Penetrating oil:** To loosen rusted parts.
* **Jack and jack stands:** To safely lift and support the vehicle.
* **Wheel chocks:** To prevent the vehicle from rolling.
* **Lug wrench:** To remove the wheel nuts.
* **Socket set:** Metric or SAE, depending on your vehicle.
* **Wrench set:** Metric or SAE, depending on your vehicle.
* **Pliers:** Various sizes, including needle-nose pliers.
* **Screwdrivers:** Phillips head and flathead.
* **Brake spring tool:** Essential for removing and installing brake springs.
* **Brake adjusting spoon:** To adjust the brake shoes after installation.
* **Torque wrench:** To tighten nuts and bolts to the correct specifications.
* **Gloves:** To protect your hands.
* **Safety glasses:** To protect your eyes.
* **Mask:** To avoid inhaling brake dust.
* **Catch pan:** To collect brake cleaner and other fluids.
* **Shop towels or rags:** To clean up spills.
* **Camera or phone:** To take pictures of the brake assembly before disassembly (highly recommended).
* **Service manual for your vehicle:** Provides specific instructions and torque specifications.

Step-by-Step Instructions

**1. Preparation**

* **Safety First:** Park the vehicle on a level surface, engage the parking brake firmly, and chock the wheels opposite the side you’re working on. Wear safety glasses, gloves, and a mask.
* **Loosen Lug Nuts:** Use the lug wrench to loosen the lug nuts on the wheel you’ll be removing. Don’t remove them completely at this point.
* **Raise and Support the Vehicle:** Use the jack to lift the vehicle at the designated jacking point. Consult your owner’s manual for the correct jacking points. Once the wheel is off the ground, securely place jack stands under the vehicle’s frame or chassis. Never work under a vehicle supported only by a jack.
* **Remove the Wheel:** Finish removing the lug nuts and carefully remove the wheel.

**2. Accessing the Drum Brakes**

* **Inspect the Brake Assembly:** Before you start disassembling anything, take a good look at the brake assembly. Note the position of the springs, clips, and other components. Take pictures with your camera or phone to help you remember how everything goes back together. Pay close attention to how the parking brake cable is attached.
* **Remove the Brake Drum:** This can sometimes be the most challenging part. The drum may be held in place by rust or corrosion. Try the following:
* **Tap the Drum:** Gently tap around the outside of the drum with a hammer. This can help break up rust and loosen the drum.
* **Penetrating Oil:** Apply penetrating oil around the center hub of the drum and let it soak for a few minutes.
* **Adjust the Brakes (If Necessary):** If the drum is stuck because the brake shoes are pressing against it, you may need to adjust the brakes inward. Locate the adjusting slot on the backing plate (usually oval-shaped). Remove the rubber plug covering the slot. Use the brake adjusting spoon to turn the star wheel inside. Turning the star wheel one way will expand the shoes, and turning it the other way will retract them. You want to retract the shoes to allow the drum to come off. You may need a flashlight to see the star wheel clearly. Some vehicles have self-adjusting brakes; if so, you’ll need to manually disengage the self-adjuster mechanism before retracting the shoes. Consult your service manual for the specific procedure.
* **Use a Drum Puller (If Necessary):** If the drum is still stuck, you can use a drum puller. This tool attaches to the wheel studs and applies even pressure to pull the drum off. Follow the instructions that come with the drum puller.

**3. Disassembling the Brake Components**

* **Disconnect the Parking Brake Cable:** Carefully disconnect the parking brake cable from the lever on the brake shoe. Use pliers if necessary, but avoid damaging the cable or lever.
* **Remove the Brake Shoes:**
* **Remove the Return Springs:** Use the brake spring tool to remove the return springs that hold the brake shoes together. These springs are under tension, so be careful when removing them. Wear safety glasses to protect your eyes.
* **Remove the Hold-Down Springs:** These springs hold the brake shoes against the backing plate. They usually have a small pin that goes through the backing plate and a retainer on the back side. Use pliers to compress the spring and turn the retainer 90 degrees to release it.
* **Remove the Brake Shoes:** Once the springs and retainers are removed, you can carefully remove the brake shoes. They may be connected by an adjuster screw or lever. Note how these parts are assembled.
* **Inspect the Wheel Cylinder:** Examine the wheel cylinder for leaks or corrosion. If it’s leaking, replace it.

**4. Replacing the Wheel Cylinder (If Necessary)**

* **Disconnect the Brake Line:** Place a catch pan under the wheel cylinder to catch any brake fluid. Use a wrench to loosen the brake line fitting. Be careful not to strip the fitting. If it’s stuck, use penetrating oil.
* **Remove the Wheel Cylinder:** Remove the bolts or screws that hold the wheel cylinder to the backing plate. Carefully remove the wheel cylinder.
* **Install the New Wheel Cylinder:** Install the new wheel cylinder in the reverse order of removal. Tighten the bolts or screws to the specified torque. Connect the brake line fitting and tighten it securely. Do not overtighten.

**5. Cleaning and Inspecting Components**

* **Clean the Backing Plate:** Use brake cleaner to clean the backing plate. Remove any rust, dirt, or grease.
* **Inspect the Backing Plate:** Check the backing plate for wear or damage. Repair or replace it if necessary.
* **Inspect the Brake Hardware:** Examine the springs, clips, and retainers. If they are worn, damaged, or corroded, replace them with new parts from the hardware kit.
* **Lubricate Contact Points:** Apply a small amount of brake lubricant to the contact points on the backing plate where the brake shoes slide. Also, lubricate the threads of the adjuster screw.

**6. Assembling the Brake Components**

* **Install the Brake Shoes:**
* **Attach the Adjuster Screw or Lever:** Connect the adjuster screw or lever to the brake shoes.
* **Position the Brake Shoes:** Place the brake shoes against the backing plate, ensuring that they are properly aligned.
* **Install the Hold-Down Springs:** Use pliers to compress the hold-down springs and turn the retainers 90 degrees to secure them.
* **Install the Return Springs:** Use the brake spring tool to install the return springs that hold the brake shoes together. Be careful, as these springs are under tension.
* **Connect the Parking Brake Cable:** Reconnect the parking brake cable to the lever on the brake shoe.

**7. Installing the Brake Drum**

* **Clean the Brake Drum:** Use brake cleaner to clean the inside of the new or resurfaced brake drum. Remove any oil or grease.
* **Install the Brake Drum:** Carefully slide the brake drum over the brake shoes. If it doesn’t fit easily, make sure the brake shoes are fully retracted. You may need to adjust the star wheel inward slightly.

**8. Adjusting the Brakes**

* **Adjust the Brakes:** Use the brake adjusting spoon to turn the star wheel until the brake shoes are just lightly dragging against the drum. You should be able to rotate the drum by hand, but with slight resistance. Avoid overtightening, as this can cause the brakes to overheat and wear prematurely. Consult your service manual for the proper adjustment procedure.

**9. Reinstalling the Wheel**

* **Install the Wheel:** Carefully place the wheel back on the hub. Install the lug nuts and tighten them by hand.
* **Lower the Vehicle:** Use the jack to lower the vehicle until the wheel is touching the ground.
* **Tighten the Lug Nuts:** Use the torque wrench to tighten the lug nuts to the specified torque. Consult your owner’s manual or service manual for the correct torque specification. Tighten the lug nuts in a star pattern to ensure even pressure.
* **Lower the Vehicle Completely:** Lower the vehicle completely to the ground and remove the jack and jack stands.
* **Final Torque Check:** Double-check the lug nut torque after driving a short distance (e.g., 50 miles).

**10. Bleeding the Brakes (If Wheel Cylinder Was Replaced)**

* **Locate the Bleeder Screw:** The bleeder screw is located on the back of the wheel cylinder.
* **Attach a Bleeding Hose:** Attach one end of a clear plastic hose to the bleeder screw. Place the other end of the hose in a clear container filled with a small amount of brake fluid.
* **Have an Assistant Help:** Have an assistant pump the brake pedal several times and then hold it down.
* **Open the Bleeder Screw:** While your assistant is holding the brake pedal down, open the bleeder screw slightly. Air bubbles and brake fluid will flow into the hose.
* **Close the Bleeder Screw:** Close the bleeder screw before your assistant releases the brake pedal.
* **Repeat the Process:** Repeat steps 3-5 until no more air bubbles come out of the hose. Make sure to keep the brake fluid reservoir full during the bleeding process.
* **Tighten the Bleeder Screw:** Tighten the bleeder screw to the specified torque.
* **Repeat for Other Wheels (If Necessary):** If you replaced wheel cylinders on multiple wheels, repeat the bleeding process for each wheel.

**11. Final Inspection and Testing**

* **Inspect for Leaks:** Carefully inspect all brake lines, fittings, and wheel cylinders for leaks.
* **Pump the Brakes:** Pump the brake pedal several times to ensure that the brakes are working properly. The pedal should feel firm and responsive.
* **Test the Parking Brake:** Engage the parking brake and make sure it holds the vehicle securely.
* **Test Drive:** Take the vehicle for a short test drive in a safe area. Start slowly and gradually increase your speed. Pay attention to how the brakes feel and sound. If you notice any unusual noises or vibrations, stop immediately and inspect the brakes.

Tips and Cautions

* **Work on One Side at a Time:** This allows you to use the other side as a reference if you get confused during reassembly.
* **Take Pictures:** As mentioned earlier, taking pictures of the brake assembly before disassembly is invaluable.
* **Use the Right Tools:** Using the correct tools will make the job easier and prevent damage to the brake components.
* **Don’t Overtighten:** Overtightening nuts and bolts can strip threads or damage components.
* **Dispose of Old Brake Fluid Properly:** Brake fluid is hazardous waste and should be disposed of according to local regulations.
* **If in Doubt, Consult a Professional:** If you are unsure about any of the steps involved in replacing drum brakes, consult a qualified mechanic.
* **Check Brake Fluid Level:** After completing the brake job, check the brake fluid level in the master cylinder and add fluid if necessary.
* **Break-In Period:** New brake shoes require a break-in period. Avoid hard braking for the first few hundred miles. This allows the shoes to properly seat against the drums.

Replacing drum brakes is a challenging but rewarding task. By following these steps carefully and taking your time, you can save money and gain a better understanding of your vehicle’s braking system. Remember safety first and always consult a professional if you are unsure about any aspect of the process. Good luck!