Brake Drums Rusted – What to Do?

Due to cast iron builds, rusty brake drums are super common. And it can happen even more if you live somewhere with a lot of road salt in the winter or high moisture in the air. And although brake drum rust doesn’t cause that much trouble, you simply cannot ignore how unsightly it looks.

So, what do you do when your brake drums rusted? Well, cleaning them off is actually a pretty simple process. You just need a few basic tools to scrub everything clean, spray it down with brake cleaner, and give it a fresh coat of paint. Then, your brakes will be like new again.

Let me walk you through the exact steps I’d take to tackle rusted brake drums.

How Rusty Is Too Rusty for Brake Drums?

So, a lot of people wonder how much rust is too much rust on brake drums before you need to clean or replace them. 

Well, the thing is the amount of surface rust on the outside actually isn’t that big of a deal as long as the inside parts are still good. Here are three things to keep in mind:

  1. See, brake drums are made of cast iron, so they’ll rust on the outside pretty easily, especially if you live somewhere with a lot of moisture or they use road salt in the winter. But that outer rust doesn’t really affect how the brakes work. 
  2. What you really want to check are the inside components, like the brake shoes, springs, and clips that hold everything in place. As long as those parts inside the drum aren’t completely rusted away, the brakes should function fine. 
  3. Of course, if the outside rust looks really heavy, it’s probably a good idea to check the insides, too. Sometimes, bad outside rust can mean the inside parts are corroding, too.

Basically, a bit of surface rust on the outside skin of the brake drum is normal and shouldn’t cause problems. 

But if the rust gets bad, lift the drums and inspect what’s going on in there. As long as those inner workings are alright, the amount of outside rust probably isn’t a dealbreaker.

How to Clean Rusty Brake Drums

Now, if your brake drums have too much rust buildup and you want to clean it off, that’s not a big deal either. It’s just a matter of gathering a few things you’ll need and getting in there to do the work. Let me walk you through how I’d go about it.

Step 1: Gather Your Supplies

Gather Your Supplies

Since you’ll have to scrape the rust off, you’ll need something for the scrubbing. And for me, an angle grinder is the go-to option for that, especially one with a 60-grit pad. It gets the job done super fast and helps you smooth everything out nicely.

But if you don’t have one of those, don’t worry – a wire brush, sandpaper wrapped around a block of wood, or even a regular scrub brush will all work, too. 

You’ll also want to have some brake cleaner spray so you can wipe everything down as you go. That’ll help keep things neat. Also, don’t forget to grab some high-heat paint afterwards so you can polish it all up and prevent future rust buildup.

Step 2: Remove the Drums

Remove the Drums

Alright, next is scrubbing off that rust. But before that, you’ll need to take those drums off, the process of which may vary depending on your specific car model. So, look up your owner’s manual if you need help. 

And if you find the drums stuck badly due to the rust, here’s a video that shows how to get it off easily:

Step 3: Grind or Scrub off the Rust

Once you’ve taken the drums off, be sure you’ve got the right safety gear on first—goggles and a mask at minimum. And maybe swap those flip-flops for a closed-toe shoe. You don’t want anything getting where it shouldn’t.

First, take your angle grinder or wire brush and start working on breaking that rust loose and scrubbing away. Depending on how bad it is, it may take a bit of time and effort. 

Then, once you break it all free, rinse the drum brakes off with water to wash away the remaining loose rust and debris. While rinsing, it’s a good idea to use wet sandpaper to scrape the loosened rusty bits.

Make sure to dry them off well afterwards, too. You want to make sure you get all that rust fully removed before moving on to the next step.

Step 4: Remove Any Remaining Dirt with a Brake Cleaner

Remove Any Remaining Dirt with a Brake Cleaner

When those drums dry up, it’s time for one last cleaning step. Go ahead and spray some brake cleaner all over the outside—that’ll help dissolve any leftover dirt, dust, or grease hanging around.

And while you’ve got everything opened up already, you may as well give those inner brake components a good spray down, too, right? No sense in leaving them dirty. Take a minute to clean any grime off the shoes, springs, clips, and other parts inside the drum.

Step 5: Apply High-Heat Paint

Apply High-Heat Paint

With those drum brakes are all scrubbed clean, it’s time for the final step – painting them up. Just give everything a nice, even coat of that high-heat paint you got.

This serves a couple of purposes. One, it protects the metal and helps prevent any new rust from forming in the future. Two, it makes the brakes look all fresh and new again. 

And since you’re painting, why leave out the outer parts of the drum brakes? You’ll want to paint them as well. After all, those areas can catch a lot of moisture.

Frequently Asked Questions

Do you have further questions regarding rusted brake drums? Here, I’ve answered a few commonly asked questions that might help.

Should I replace the drum brakes when it’s rusted?

I wouldn’t worry about swapping them out solely due to rust. Just inspect the internal parts, and if those still look okay, the drums are usually fine. The real thing that causes replacement is normal wear over a lot of miles—usually around 150,000 to 200,000.

Can I use WD-40 to remove rust from brake drums?

WD-40 can help remove some rust from brake drums in a pinch, but it’s probably better not to use it in the interior part. This is because it can leave a bit of an oily film behind that’s not good for the brakes. So, it’s better to use a dedicated brake cleaner spray instead.

Can painting brake drums decrease their performance?

Not a chance. In fact, it can help them work better longer. As long as you use high-heat paint meant for brake components, it won’t degrade or come off from the heat of braking. Plus, high-heat paint is formulated to handle the crazy temperatures of brakes without cracking or peeling.

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