How To Rebuild Rear Drum Brakes

Rebuilding drum brakes is one of those things that becomes a common chore if you’ve got older cars. It takes no special skill, just knowledge of where everything goes and the confidence to do it. I avoided my brakes as much as possible early on, afraid of doing something wrong – but after assisting in the process a few times, it’s now a simple, routine procedure (although I still absolutely abhor bleeding my brakes, with more practice that will probably become a breeze too).

If you’ve never rebuilt drum brakes or changed your drum brake pads before, don’t be afraid to tackle it the next time it needs done on your car. If possible, having an expert walk you through the first time is ideal – but I’ll be as thorough in my instructions as possible so you can use this as your guide. Remember that while drum brakes are generally the same, many makes and models have their individual quirks – for example, my friend Jen’s Plymouth has two brake cylinders per wheel instead of just one!

Let’s start with figuring out what to call everything…

Diagram courtesy of www.allfordmustangs.com/forums

Before you start, keep in mind:

• Stopping your car is even more important than making it “go”. Keep safety in mind and get a knowledgeable helper if you’re unsure about anything! A great thing about car folk, is they’re usually willing to explain something or help if asked.
• Brake fluid is toxic and will strip paint. If you’re only changing pads, you won’t disrupt your hydraulic brake system – but if you’re rebuilding them, then you’ll be opening your brake lines. Keep in mind that brake fluid needs to be disposed of correctly and take great care to keep it away from anything with paint.
• Another thing to know about brake fluid is that it will absorb water over time, aka “hydroscopic”. Meaning that every 2-3 years you should do a brake fluid flush in your system, bleeding out the old and replacing it with new. Also, if you’ve had an unsealed brake fluid container sitting around on your garage shelf for more than a year, you should  replace it.

Okay, time to get to work! Here’s what you’ll need to rebuild your rear drum brakes:

• Lug wrench, ratchet, or impact gun with proper sockets to remove your wheel with
• Screwdriver and/or brake spring tool
• Anti-seize lubricant
• Liquid Wrench or similar lubricating oil
• Suggested: line wrench for removing brake lines without stripping bolts
• May come in handy: rubber mallet, pry bar
• New brake shoes
• Brake rebuild kit/wheel cylinders as needed

To start with, jack up your car and remove your rear tire (read Changing a Tire 101 if you need more details on this). From there remove the drum, if it’s an old rusty car that’s been sitting, this could take some effort. Now you may see a couple slightly different looking set-ups. On set-ups like mine, there is only one hole that must be rotated to get at all four nuts below – some others have holes all the way around so you’ll see the bolts needing to be removed a bit easier.

Loosen and remove the nuts connecting the axle to the drum. My Chicago Pneumatic impact gun makes short work of this – when using air tools: be cautious of its power, double-check the direction it’s working, and protect your hands with gloves.

Once those nuts are removed, you can pull out the rear axle. You may find it comes with a healthy tug…other times might require some extra muscle. Jiggling it and giving it a smack with the mallet may help to coax it out if its giving you a difficult time.

Once it’s loose, pull it all the way out. Now you’re left with just the brake apparatus. First you’re going to pull apart the brake pads.

Using a screwdriver, pry each return spring from the anchor pin one at a time. These always scare me, thinking they’re going to spring off and hurt me…but they don’t. If it makes you feel better, wear safety goggles and gloves (like you should be doing already).

Next you’ll remove the shoe hold-down springs. They make a special brake spring tool that will help with this (mine’s from GearWrench, I love their softer-handled tools), but the job can be done without it. You just press on the covering plate as you rotate the opening to pop off the pin that’s holding it down.

After both of those are off, you can pull the brake shoes apart and take them off…you’re well on your way! After detaching the hard brake line at the back (using a line wrench, that’s a wrench that has an extra side closed…a good addition to a basic toolkit which will help protect the fragile brake line nut), you can now pull the whole backing plate off. There should be an emergency brake cable to remove across the bottom, you can just disconnect that and pull it out the back.

If you’re rebuilding the brakes, you’ll want to replace the wheel cylinder. This part is where your brake line screws in and is the end of your hydraulic brake system and what ultimately pushes out your brake shoes to cause your car to stop. Mine’s connected by two small bolts accessed on the back of the plate.

Some people choose to rebuild their wheel cylinders, but you can also just purchase completely new ones – as they’re not expensive for this car, I just bought new ones. Before putting the new wheel cylinders on and everything back together, I cleaned and painted the Falcon’s backing plates. This isn’t something that has to be done, but if you’re in the process of restoring a car you might as well do the complete job! My Mister loooovees painting bits and pieces bright green (since this isn’t the Studie, I consent), you can choose whatever color you want as it will hardly be seen and that only when looking underneath your car. As this isn’t a high-temp area, normal spray paint can be used.

Now you can begin to put the rear brake shoe back together on a level surface before putting it back on the car. While you may want to replace the springs, etc with a brake rebuild kit, we didn’t feel the Falcon needed that.

People may not realize that the material of the brake shoes are two different sizes, but they are…so which brake shoe goes where? They need to be placed correctly, but remembering which one goes where can be difficult. The longer pad goes on the rear side, the shorter one goes to the front. Here’s the reasoning if it helps you remember… the wheel uses the primary (front) shoe in order to push out and engage the secondary (back) shoe, making the back shoe do a majority of the actual stopping work – thus the back shoe has a longer (larger) pad area. If you forget which goes where, bookmark this site and article to find again and remind you.

Before replacing the adjuster screw (or adjuster assy per diagram…I’m working on my vocab, I promise), give it a good cleaning and lubricating. If you haven’t changed brake shoes before, you’ll find out that the adjuster assy is extemely important. Once brake shoes are all put together in your car, they need a little adjustment to help them work correctly…which is where this part comes in. By sticking a flat screwdriver or similar object through an opening in the backing plate, you’ll rotate this adjuster screw and it will either push the shoes slightly apart or release tension and bring them slightly closer inwards.

I keep a bottle of Liquid Wrench handy for such things. You want the gear part to move easily – so when it comes time to adjusting those new brake shoes you’ll minimize the frustration or swear words (which you’ll know what I’m talking about if you’ve ever been unsure about what direction to turn that darn thing!)

Another bit of lubricant is needed to ensure your brakes work in top-form. This nifty Anti-Seize Lubricant will do exactly what it states it does, put it on the flat surfaces of the backing plate which come in direct contact with your shoes.

And even though you lubed up your adjuster assy, you can dab the Anti-Seize stuff on those moving parts as well. I got a little slopy, thus the silver stuff on the spring and outside.

Now you’re ready to start putting parts back together. With the shoes and adjuster assy in place, you can attach them to the backing plate with the two shoe hold-down springs. Poke the rod part up through the plate, place the spring atop it (flat side up), then place the spring plate on top through the rod. Using a brake spring tool makes the job of getting this pressed down and together easier.

The shoe springs come next, and they must be connected to the primary and secondary shoe then secured to the anchor pin. Using a screwdriver to hold and stretch the spring, guiding it onto the pin, as shown below, is the best way to go about this (I believe they make a hook-shaped tool for this also, but I don’t think it’s particularly necessary).

Now that it’s all held together we can put the backing plate and shoes back on the car. If you’re not already 110% sure of which direction loosens and tightens your brake adjusting screw, I’d recommend doing a test “mock” adjustment now, before it goes on the car and can’t be seen so easily. Poke a screwdriver through the hole on the backing plate, just as you would do if it were connected to the car, and make a note of which direction pushes out the shoes (tightening the brakes) and which brings them back in.

Before putting the adjuster plate back on, you’ve got to re-gasket the plate at the wheel hub. While they do sell cut gaskets for this, my husband and other mechanics recommend using “The Right Stuff”. There is a certain art to getting this stuff out of the tube correctly, you need a consistent and even line for the best working gasket. Do a practice on some newspaper if you’re doing this for the first time…it should look at least as good as the line in the picture below.

With the gasket on, you can place the backing plate on, fitting the four bolts through their proper openings. Next insert the axle, turning and wiggling it until it splines up (you know it’s splined if it pushes in completely). Bolt this down like how you removed it – on mine I have to rotate the plate to reach each bolt/nut. The nuts can be a little tricky to get in there, but there should be ample room to fit your fingers and get each nut started.

Almost done! It’s time for the drum to go back on. Spray some brake cleaner liberally inside the drum, and use a clean rag to wipe out any residue. You’ll place that over everything, then before replacing your wheel connect the brake lines. These boogers can be difficult to get started…be patient. Apply pressure while turning the bolt. And always be very gentle with your hard brake lines and nuts, they’re easily bent/stripped.

Now you can replace and properly secure your wheels. You’ll need to bleed your brakes (I suggest having a friend help with this rather than trying to do a 1-person method) and adjust your brake shoes. How do you adjust your brakes you ask? You want the wheel to rotate freely, but just “just”…meaning using the adjuster assy that we talked about earlier, get them barely to the point where it’s catching (when you’re not pressing the brake pedal). Then let it off a little bit from there, so that it actually is rotating freely. You want the brake shoes to have the least amount of travel as possible in order to catch the drum…this and a well-bleed system should ensure that your brake pedal is working optimally!

I hope this brake tutorial helps you in your process of learning! If you’d like to continue reading on drum brakes, I found this autoshop booklet that’s a good read. Every time your car breaks or needs maintenance done is an opportunity for learning and new adventures, so put some grubby clothes on and get greasy! Be sure to bring in help when needed and stay safe!

Happy Trails,

Kristin