Reasons to Perform Brake Drum Replacement

Brakes, Tires and Wheels

By Rodney (Mechanics)

Why is brake drum replacement crucial? Well, there are so many different parts of the vehicle that contribute to the perfection or smooth operation of the ride, and brake drum is no different. Even the smallest parts have important role in the running and safety of the vehicle, which means that replacement shouldn’t be considered lightly either. But before we dwell further about the replacement, you need to know the details of the brake drum and its overall function.

Reasons To Perform Brake Drum Replacement

Understanding Brake Drum Function

A brake drum is a part of braking system that is made from heavy cast iron. It looks like a shallow cylinder (several inches high) that has between 9 inches and 12 inches of diameter. When you apply the brakes, the brake shoes will make contact with the machined surface surrounding the interior circumference. The function is to transmit the hydraulic pressure via the wheel cylinder.

The action will force the (brake) shoes to go outward against brake drum’s interior, which leads to friction. It causes the car to move slower. The drum itself would be fully encloses and then mounted over the rear braking components, including brake shoes, parking brake mechanism, clips, springs, and wheel cylinder. The drum itself is typically held to the (wheel) hub by the lug nuts and wheel. But in some vehicle, the configuration is combining the wheel hub and the drum as one single unit. Nowadays, in this modern era, the drum brake system is attached and installed on the rear side axle. If used completely, there would be 4 wheel disc systems in which it would be considered more common.

Brake Drum Replacement

When Is Break Drum Replacement Needed?

There are certain specific moments where you will have to replace the brake drum. So, when do you need to have a brake drum replacement?

  • When the braking effectiveness has been reduced. When the drum is cracked, scored, and worn unevenly, it will result in increased stopping distances. A scored drum must be replaced on the outright, but a worn drum is still manageable to be restored within a brake lathe, provided that it still has sufficient material left.
  • Pulling to the side, noise, vibration, or pulsating brakes. When a drum is somewhat warped or unevenly worn (or even the shoes have completely been worn down), it will result in metal to metal contact. You should be able to detect the car pulling to a side, hear a noise, feel a vibration, or sense pedal pulsation whenever you apply the brakes. It’s time to inspect the car up to a pinpoint stage so you know the exact core of the issue.
  • Brake shoe replacement. Whenever you replace the brake shoes, you also need to replace or resurface the drum. If you install new (brake) shoes on an unresurfaced and used drum, it can lead to poor outcome
  • Parking brake function loss. You see, the parking brake would lock the (brake) shoes against the drum. If the drum is worn and cracked, the brake lever has to work excessively in pulling. Instead of completely stop, it can still roll continuously. However, the more common and general situation is about parking brake maladjustment or parking brake components seizure. When you repair those issues, you may have to remove the brake drum.

Brake Dust And Rust

Brake Drum Replacement Mechanics

When you perform brake drum service, you have two options: you can resurface or perform outright replacement. In most cases, replacing the drum would be cheaper than refurbishing it. However, when we are talking about both cases, the procedure to install or remove the drum would be the same.

  • Raise the vehicle. Make sure to support it safely by using the steel jack stands
  • Remove the assembly of wheel and tire
  • Remove the brake drum. In the event that the brake drum has rusted over (to the wheel hub), you will need a (brake drum) puller to remove the drum. In specific cases, wheel hub would be integral to brake drum, which means that the hub bearing will retain bolt. And the wheel bearing should be removed too in order to replace the entire drum
  • Measure the diameter of the interior by using micrometer. If there is enough metal, the mechanics will likely resurface the drum (on brake lathe)
  • Before installing the new (ore resurfaced) drum, wheel cylinder, backing plate, parking brake mechanism, springs, and brake shoes would be checked. If the parts are worn, they should be replaced. Typically, when drums are resurfaced or replaced, new shoes must be installed.
  • Mechanics would adjust the shoes and then he will install the drum. And then he will work on the tire and wheel assembly and then torque within proper sequence. Then the mechanics would perform road testing of the ride

New Brake Drum Replacement Installed

Things to Remember when Replacing the Brake Drums

Here are some helpful tips that you can do to make the process easier and also more efficient:

  • There are some exceptions where you may have to perform brake work on both ends (of the axle) even though the work is only needed on one end. When a drum (on rear axle or one end) must be serviced or brake shoes at one end are being serviced, both sides must get the same service. This is helpful to prevent and avoid problems, like vibration, pulling, and others.
  • The brake drums incorporate extremely strong springs so the braking shoes will stay in position. Unfortunately, these brake springs are often exposed to extreme heat. It would be a good idea to replace all of the springs whenever you install new shoes. In the event a spring suddenly break within the braking drum assembly, the miss-positioned shoe will cause grab and lock mechanism on the brakes, which is risky and is a part of safety issue
  • It’s possible that the mechanic suggests wheel bearing grease and also wheel bearings inspection in the event the wheel bearing and hub are integral to your car’s brake drum
  • Be advised that the brake shoes arc won’t match perfectly with the new drum arc. Expect or be ready for a bed-in period before you can achieve maximum (braking) efficiency.

Those are the detailed parts about brake drum and its function. With proper brake drum replacement, your car can run well.