We need brake drums in older cars to help with deceleration and stopping. But after 1998, Brake drum replacement was by rotors, although they are still in older cars. Brake drums work by generating friction between the brake pads and the drums to reduce the wheel's rotation, which brings the vehicle to a stop.
Brake drums are an important part of the brake unit in a car, and they are applied on the rear axle in cars. To know when the brake drums in your car should be replaced, you should notice when the rear brakes are getting less effective. Then you need to check the braking system. In this article, you get to learn everything about brake drum replacement, how much it costs, and more.
What are brake drums?
Brake drums are used in cars to help control the speed and movement of a car. They also perform the same functions as disc brakes in newer car models, which control wheels' movement in cars.
They use friction-lined brake shoes inside its drum for brake drums instead of brake pads over a disc brake. Brake drums have a longer shelf life than disc brakes and are more affordable than disc brakes, which are more popular in today’s cars.
Brake drums are built with a braking mechanism on the inside, unlike disc brakes. The brake drums and shoes are essential in a car’s braking system. They are mostly found in older vehicles that don’t require a disc brake system to control the car's speed.
Newer car models use disc brakes to control movement, and the brake shoes function as the brake pads. The brake drum is like a bowl-shaped object attached to each wheel on the car. So, when you are driving a car, and you step on the brake pedal, the brake shoe pushes on the brake drum, which creates friction that slows the car's wheel down when in motion.
It is similar to how the brake disc works; it is just an older version with more technicalities.
Symptoms of damaged brake drums
Brake drums are made from iron. For brake drums, one side comes in contact with the brake shoes. Over time, from the contact, the brake drum begins to wear out from use. How do you know when the brake drum and shoes in your car are getting worn out and due for a change? The following listed below are the symptoms of damaged brake drums and shoes.
Brake pedal vibrations
As the brakes are being used in a car's movement, the brake drums begin to wear out in the process. When they wear out, vibrations will be felt from the brake pedal while your foot is on it. Vibrations from the brake pedal are an early symptom of a damaged brake drum and shoes.
The parking brake is loose.
For a car to be parked properly without any further movement, the parking brakes need the brake shoes to press firmly against the brake drums.But if the brake drum is damaged or faulty, the parking brake won’t function as it should, so the car won’t park properly. The parking brake will feel loose, and in turn, the vehicle will have loose parking.
The brakes are present in the car to bring the car to a halt immediately when pressed on. If the brake pedal is stepped on, and the car does not slow down or halt immediately, it means that the brake drums and shoes are faulty.
Brake scraping noises
Damaged brake drums and shoes create scraping noises on the brake pedal. This happens because the brake drums are not essentially made to absorb a lot of heat from the braking system. Over time, the brake shoes against the brake drum will cause friction and, in turn, produce loud noises from the car.
When should you replace a brake drum?
Typically, the brake drums should be replaced when they are faulty or show any of the above symptoms. But, do you know why they should be replaced? In a braking drum, the two parts that need to be changed whenever an issue arises are the shoes and the drums.
The brake shoe is the inner part of the system that pushes against the brake drum, thereby creating enough friction to slow down the vehicle or halt it. The brake drum and the shoe absorb the energy created in the wheels while the car is in motion, so they need to be changed or checked from time to time after absorbing so much energy.
Once you notice that your car responds to the braking commands slower than normal or is now less effective, they should be checked immediately.
Sometimes, the brake drums can be maintained without replacing the entire set. But after a while, they should be replaced if the drum thickness is below measurement.
To change the brake drums in your car, you need technical tools and know-how about how brake drums operate. The brake drums should be changed when the iron's thickness used to make the drums goes below the value shown on the measuring tool.
Steps involved in replacing brake drums
Changing a brake drum is a complicated process, which often needs the knowledge of a professional. This process involves removing the wheel and disjoining the drum, which is also connected with removing the wheel bearing and replacing the brake shoes. To replace the brake shoes, the brake shoe adjuster lever also has to be disassembled.
The parking brake, also known as the hand brake, functions due to the brake drums. That is why the parking brake must be removed from the shoes and then fitted back in place. A wheel bearing removed with a wheel cannot be used again and must be changed.
Also, in changing the brake drums, the brake fluid compartment's braking fluid has to be checked. Also, a special tester should be used to check the boiling point of the brake fluid. A set of drums should last for 100-150 kilometers before changing them or checking them.
Tools needed for brake drum replacement
Brake drum replacement depends on the make and model of your car. To do this, the vehicle has to be jacked up and then the wheels removed to have the drum exposed. The drum is held in place by a small clip, while the drum stays on the axle of the vehicle and is held further by dirt.
If the drum is all that needs to be replaced, a rubber mallet and penetrating oil can be used easily. If the drum is working, the shoes then need to be replaced. The shoes are held in place with springs, and to get them out, a manual is to be used. To carefully remove the brake drum, these are the tools you need.
- Brake cleaner
- Brake shoes
- A digital micrometer
- Brake drum
- A brake drum adjustment tool
- Dust mask
- An auto-jack
- Jack stands
- Needle nose pliers
- Oil drain pan
- Ratchet and socket assortment
- Safety glasses
- Drum brake tool kit
The steps involved in brake drum replacement
Loosen the nuts of the two rear wheels. Also, remove any wheel hubcaps that cover the lug nuts.
After loosening the lug nuts, the front wheels should be secured using wooden blocks to prevent the car from moving when being worked on. Once the front wheels have been secured, the jack stands should be used on the car.
Carefully remove the wheel, and reveal the brake drums. The brake drum is removed by moving it from side to side to pull it away from the hub. If the brake drum seems to be stuck in place, more force can be applied. If the drums are secured with screws, they can be unscrewed using the appropriate screwdriver.
After removing the drum brake, you should see the shoes, springs, and wheel cylinder. Before disassembling the parts, use an oil drain pan under the drum brake, then spray the area with a brake cleaner. Also, spray the areas that are dirty or where brake dust has settled. Brake dust causes noises, vibration, and friction in the brake compartment.
Inspect the brake components by measuring using a digital micrometer reading in inches. The brake drums should be measured for cracking or grooving. While the brake shoes should be very thick and should not be less than 1/16th in inches, they should be replaced if they are. Also, in checking the brake components, the wheel cylinders should be checked for brake fluid leaks.
After inspections and measurements, the brake assembly can be disassembled. Needle nose pliers should be applied to remove the brake shoe retaining springs. The topmost spring should be removed first, making the lower springs easier to remove.
After the retaining springs have been removed, the drum shoes can be moved out freely. The drum shoes are secured with pins and washers, which can be easily removed using needle-nose pliers.
After the drum shoes and brake have been removed, check the wheel cylinder for any leaks. Leaks in the wheel cylinder show leakage of brake fluid. If there is any leakage, the brake wheel cylinders should be replaced immediately.
Carefully remove the parking brake cable retainer clip using a flathead screwdriver or twisting the retainers using a pair of pliers.
Clean the backing plate with brake cleaner.
Install the brake shoes and drums.
Install the adjusting screw assembly and spring.
Secure the brake shoes to the hub using pins and washers.
Put back in place the tensioning springs in the reverse process, which they were removed.
Install the hold-down pins and springs from the brake drum assembly.
Install the return springs by putting the spring on the brake.
Adjust the brakes with a brake spoon or screwdriver to allow the brake shoes to expand. This is done so the drum can be turned using one’s hand.
Prepare the new drum brake set. Spray the brake drum with a brake cleaner to remove any thin oily film before installation.
Install the drum brake over the drum shoes by slipping it over the brake shoes.
Tighten any adjustments that need to be made. If the brake shoes are loose, it will cause problems for the parking brake. If it is also tight, it will damage the drum and shoes. Adjust the shoes from the brake adjuster.
Now install the wheel and tire and tighten the lug nuts that were removed previously.
Remove the jack stands holding the vehicle carefully until the car is on the ground.
Using a torque wrench, torque the wheel nuts to fit.
Test your brakes by taking the car for a test drive till you are confident that they are working properly.
The longevity of a brake drum is dependent on the way you drive your car. Although it depends on the quality, a brake drum typically lasts for 100,000 - 150,000 miles.