Drum brakes have been around for more than 100 years, and they’re still in use on some modern-day applications, but for the most part, disc brakes have taken over for regular passenger cars and light trucks. This transition has encouraged gearheads to make the switch on old cars, and several companies offer front and rear disc brake conversions for most applications from the ’50s to the ’80s. The truth of the matter is that the average car enthusiast upgrades the front brakes and leaves the rear brakes in the stock configuration. This combination performs nicely on something that isn’t seeing track time or intense driving, but those rear drums need attention from time to time.
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Our subject is a crusty ’77 Nova that runs and drives nicely but needs some attention. The first step is removing the drum, which may be difficult, depending on how much rust has built up around the axle flange.
Because of the factory brake bias that puts more emphasis on the front brakes, you’ll rarely encounter rear drum brakes that are badly worn. Usually, it’s more of an age issue than a wear issue when it comes to rebuilding rear drum brakes. Our ’77 Nova project car is a true daily driver, so we wanted to be proactive about the brakes. We upgraded the front brakes with Summit Racing rotors and new calipers, and we continued our brake service with OE-style brake service parts from Summit Racing. We opted for AC Delco brake drums (PN ADO-18B80), AC Delco brake shoes (PN ADO-1424B), Dorman wheel cylinders (PN DHB-W45999), and a Summit Racing spring kit (PN SUM-7104K). These parts were readily available and barely put us over the $100 threshold, so we could take advantage of Summit’s free shipping offer. We had already replaced the rear brake flex hose previously, so adding that to our order would’ve added a few bucks more.
If you’ve never worked on drum brakes, it’s a good idea to snap a few pictures of the inner workings before you tear it down. Old pros know the proper rod and spring placement, but it can be confusing so a reference picture can be helpful.
This is a project you can tackle at home with standard tools, although Summit Racing does offer special brake tools to make the job easier. After the car was back together, we bled the brakes, starting with the passenger side and then the driver side. You will also need to adjust the brakes to take up any slack between the shoes and drums. This is accomplished by twisting the adjuster screw that rides between the two shoes at the bottom. This can be done with the drum off by taking pressure off the adjuster plate and twisting the adjuster. Or you can adjust with the drums on by using a flat screwdriver to grab onto the teeth of the adjuster through the small oval hole in the backing plate.
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Summit Racing offers a Drum Brake Repair kit with the proper tools to remove the springs, but we grabbed our favorite pair of Knipex Cobra QuickSet pliers and grabbed onto the spring that goes from the rear brake shoe to the hook on the brake shoe rod.
We rebuilt the rear drum brakes in a couple hours in the driveway and had our Nova back on the road with all-new components to put it back to its original condition.
Next is the spring that runs from the front brake shoe to the anchor bolt. It’s best to grab the spring near the coils, get a tight grip, and pull firmly to get past the flange around the anchor bolt.
Follow along with the steps and put this on your to-do list if your classic Chevy is still relying on drum brakes.
The pliers are used once again to remove the brake shoe rod from the anchor bolt. The easiest place to get a grip on the rod is the hook where the rear spring attaches.Special tools are available for these pins and clips, which hold the brake shoe onto the backing place, but our pliers do the job again. You’ll want to hold the pin on the back side, press in on the clip, and then turn it 90 degrees to release it.Now the brake shoes and adjuster assembly can be removed by spreading the shoes around the axle flange. Once the shoes are past the flange, we can twist them in a way that allows the parking brake bracket to come out of its slot.The parking brake bracket is still hanging by the cable, and it can remain in place. Feel free to spray it off with brake cleaner and dust a light coat of paint on it while you’re dressing up the backing plate.If you’re still unsure about the arrangement of all the pieces, lay them out on the ground as you disassemble, taking note of the direction of the springs.It’s a good idea to soak the brake line fitting with penetrating oil and always use a line wrench when loosening it. If it’s stubborn, heating it moderately with a propane torch is helpful. After the line is loose, remove the two-wheel cylinder bolts.The new Dorman wheel cylinder (Summit Racing PN DHB-W45999) bolts into place, using the original bolts, and you’ll also need to reuse your original push pins. They simply push into place.We tightened the wheel cylinder bolts, then reattached the original brake line and made sure the bleeder screw was tight.Brake cleaner is used to remove some of the gunk off the hard parts that we’re reusing. The adjuster assembly, brake shoe rod, brake strut, and anchor bolt guideplate are not parts that typically come in a rebuild kit.After cleaning, we install the adjuster between the new AC Delco shoes (Summit Racing PN ADO-1424B) and stretch the new adjuster spring into place before installing the shoes on the car. Take note that the taller shoe goes toward the back of the car.Now we can spread the shoes to clear the axle flange and loosely fit the shoes to the wheel cylinder push pins. We also feed the parking brake bracket into the rectangular hole in the rear shoe.The rear brake strut is a flat piece of steel that rides between the two shoes. The Summit Racing kit (PN SUM-7104K) came with a new spring, which slides over the end of the strut that faces the front of the car.The spring kit comes with new pins, springs, and clips that hold the brake shoes in place. We once again use our pliers to grab the clip, press in on the spring, and then twist to engage the lock.There is a little more wiggle room on the front shoe, so we could install the other pin, spring, and clip by hand.We first install the anchor bolt guideplate, then hook the shoe rod into the rear shoe. Using the spring hook, we pull the rod until it slides over the anchor bolt.The blue spring is used on the front shoe. It hooks into the shoe and then we used pliers to pull the other end over the anchor bolt.Finally, the green spring is used on the rear shoe and connects the shoe to the hook on the shoe rod. After all springs are installed, you may need to manually move the shoes around to get them situated properly.Before we button it up, we visually inspect the brake assembly to make sure all pins, springs, and clips are in the proper positions.Although the old drums were serviceable, we opted for new AC Delco drums from Summit Racing (PN ADO-18B80). We blasted on a couple coats of cast gray paint and slid the drums over the studs.Now we can add DOT 3 brake fluid to the master cylinder and pump the brakes up. It shouldn’t take long to get fluid back to the new wheel cylinders.The final step is bleeding the brakes, starting with the passenger side wheel cylinder. Once it has clear fluid with no air bubbles, we move to the driver side to complete the job.
