Until the 1970’s most vehicles other then high performance models had drum brakes on all four wheels after that time disk brakes were standard on the front of many vehicles and many went to four wheel disk brakes. Today you are likely to see drum brakes on base model vehicles on the rear wheels however some manufacturers are moving away from drum brakes all together.
The reason drum brakes are still acceptable on the rear of lighter vehicles is because they provide decent stopping power and they provide an easy method of introducing an emergency brake feature. Emergency brakes on four wheel disk brake models still use a mechanical method of stopping the vehicle but introduce complexity in the rear disk design.
Here we are working on a honda civic type rear wheel drum brake system. Most manufacturers follow a very similar design with differences only in the hardware clips and springs that hold the shoes to the backing plate.
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Parts That Make Up A Drum Brake System
In the illustration to the left you can see some of the parts that make up a rear wheel drum brake system as it is assembled with the drum removed.
As we progress in this howto you will be able to see some of the parts in better views.
1) Wheel Cylinder
2) Brake Shoe or Pad
3) Top & Bottom Brake Shoe Springs
4) Brake Shoe Retaining Clip
5) Brake Backing Plate
6) Emergency Brake Cable
7) Self Adjuster Spring
8) Self Adjuster Rod & Clip
As you can see there are many parts that make up a Drum Brake System but if you work slowly and lay out parts as you remove them it is a pretty easy process to remove, repair and reassemble a drum brake system.
IMPORTANT NOTE
The first rule of working on drum brakes no matter how experienced you are is that you only work on one wheel at a time. This will allow you to pull the drum from the opposite side and use it as a reference to double check spring locations and clip placement.
Because this vehicle has been sitting for an extended period it will be important to purchase a drum brake hardware kit that will include all of the springs, the shoe retaining clips and pins and the C-Clip that is use to attach the emergency brake arm to the rear shoe. Cost is about $20 for both sides and worth replacing on a vehicle with many years or miles.
If there was a problem with a leaking wheel cylinder we would have the choice of purchasing a rebuild kit with seals and rubber boots for about $10 for both sides or new wheel cylinders for about $25 per side. If you notice fluid leaking from your drum brakes before you open them make sure you order a seal kit when you get your shoes.
NOTE: It is very important that you take proper safety precautions when working on your brakes. It is not only important to do the job correctly but to do it in a method that is clean. New brake pads should not contain asbestos but older vehicles may have pads that still have asbestos in them. Inhaling even a small amount of the dust can cause problems over time (not immediately but after months or years). YOU MUST WEAR A DUST MASK OR RESPIRATOR AT ALL TIMES and as normal you should wear hand and eye protection whenever performing work.
Getting Started
Jack up the vehicle and support both sides of the rear of the vehicle with jack stands. Use chocks on the front wheels to stop the vehicle from rolling.
To free up stuck parts you want to pump the brakes with the wheels still on about 5 times and apply the emergency brake then release it fully before removing the wheels.
Remove the rear wheels and place them under the frame of the vehicle for extra safety.
Remove the brake drum of the side you will be working on to expose the brake hardware. If you have difficulty removing the drum then pry it slowly and gently with a prybar around the drum and away from the backing plate. Sometimes tapping the drum with a large hammer gently but firmly will release the drum if not you will have to refer to your manual on how to either back down the brake adjuster or use extraction bolts to remove the drum.
Once the drum is off you want to inspect the inside of the drum for deep groves. A very slight waviness of less then a 16th of an inch or just enough to barely catch your fingernail would mean you probably do not need to have your drums cut or turned at a machine shop however the drum could still be out of round (concentric) which means that it wore unevenly and needs machining to make it a perfect level circle. If so then you will have the choice of just replacing the drum or having them cut. On smaller vehicles drums are inexpensive $35 per side on larger vehicles and trucks you almost always want to cut the drums at least once before throwing them away.
CLEANING THE BRAKES
Now that the drum is off and the old brakes are exposed you will probably notice a large amount of dust. It is important that you do not breath this dust so you must clean the old parts before you remove or work on them… Sounds a little strange doesn’t it but you need to do this.
NEVER USE YOUR HOME OR SHOP VAC TO REMOVE BRAKE DUST if you do the vacuum with be contaminated and spread the dust throughout your shop. Professional shops have special vacs that are dedicated to brake dust.
Get a large plastic cat litter box and place it below the wheel with exposed parts and then using brake cleaner wash the surfaces of the shoes, parts and backing plate well to remove the dust and grease. Expect to buy at least 2 cans of cleaner for the job. If you have ABS Brakes always use abs rated cleaner.
Once you remove all the parts you will need to clean the backing plate again after you have wire brushed all the rust off the contact points.
Removing the old brake shoes
Once you have cleaned the loose dust off the old parts you can begin to disassemble your parts.
You should have an open work area where you can lay out each part in the same locations as they were assembled. A few sheets of newspaper or on a workbench.
You must also remember the order that parts were removed because you will replace them in reverse order.. It gets pretty tight in there so doing things in order is often the only way to make them fit … without having a fit… heh.
Removing the Brake Springs
Some people like to use side wire cutters to remove and replace brake springs because it is usually the best tool they have to get a tight grip on the spring but by doing so you risk the chance of introducing a cut line in the metal which will fracture over time. Specialized Brake tools are available to remove springs and clips but a pair of needle nosed vice grips really works well.
Before you take the top spring off you must note how the spring is installed. You will see that there is a straight flat section in the coil of the spring that is about a half inch long. This is very important! Notice how the straight section is at the top of the spring when installed so it will not interfere with the self adjuster wheel. In your kit there will be two bottom springs that are identical and two top springs that are different colors and opposite. If you put the wrong side spring on then your brakes will not self adjust.
Pry the end of the spring away from the shoe with a screw driver and attach the vice grip then pull outwards towards the front or back of the car and then out and away from the shoe. This will take a little muscle to remove the spring so get a good grip and make the vice grip as tight as you can.
You dont need to get both sides off as long as one side is free you can proceed to removing the clips and the springs will come off with the shoes if you do get them off then lay them out as removed.
Removing the Brake Shoe Clips
Next you need to remove the clips that retain the brake shoes to the backing plate. The clip is used to hold a pin that is inserted from behind through the backing plate then through the brake shoe and held in place by the clip.
If you look close you will see that there is a slot in the clip and the end of the retaining pin is flat.
In order to remove the clip place your finger behind your brakes and find the end of the pin on the backing plate. Hold it firm against the backing plate as you use a pair of plyers to press down on the clip end that is not hinged to compress the clip.
At this point you can either rotate the pin from behind the backing plate with your finger that is holding it in place or you can rotate the clip.
Some manufacturers use two clips on each shoe (as you can see in the picture there are empty holes on the shoe for these clips not used here) and they may have round heads with a coil spring behind them. The method to remove these clips is pretty similar but you will be better off rotating the clip and not the pin to get the head to line up with the slot.
Self Adjuster Removal
Take note of how the Self Adjuster clip and spring are attached to the front shoe on this side of the vehicle.
When you are removing the retaining clips and springs it is easy to not notice that the clip is inserted against the shoe and under the self adjuster rod.
This will be very important wen you reinstall the shoes as the self adjuster clip and spring will be on the shoe as you insert it.
The Self Adjuster Rod that rotates and is positioned between the shoes can be removed when you remove your first shoe. Remember to take not as to which side of the self adjuster is inserted into the front shoe. Usually it will have a notch in one of the forks making it shorter which allows it to slide behind the emergency brake lever on the rear shoe. Also the wheel of the self adjuster will line up with the access hole on the back of the backing plate.
Emergency Brake Lever Removal
When you remove the springs and retaining clip for the rear shoe you will notice that the emergency brake lever is still connected to the brake shoe by the cable.
It is very important to remember how the show was removed from the cable.
Do not attempt to remove the C-Clip holding the shoe to the emergency brake lever. Instead rotate the pad towards the ground and you will be able to compress the spring end of the cable.
The cable has a sheathing that is also a spring. Holding the cable in place with your finger against the backing plate force the end of the emergency brake lever into the spring to compress it then work the cable end free from the lever through the hole provided.
This is harder to write then actually do but you need to remember how the shoe was positioned when you reattach it later.
Inspect your Wheel Cylinder For Leaks
Now that you have your shoes off you can use your finger or very lightly a screw driver and peal back the edge of your brake cylinder dust boots.
You need to do this on both sides to look for brake fluid that is getting past the seals.
The Dust Boots do not retain the brake fluid and can not retain high pressures so if you have a damaged seal you are likely to see a lot of fluid leaking but if you have a seal that is about to go bad you may see some moisture.
If you do see moisture then it is time to replace the seals.
Inspect the dust boots for any tares that could allow dirt and moisture into the wheel cylinder.
You can buy boots and seals for under $15 that will allow you to repair the parts to new unless there is corrosion in the piston walls of the wheel cylinder. PLEASE see our other HowTo on Wheel Cylinders for more information.
Cleaning the Backing Plate
Ok, so we are about half way done so far. Now that we have removed all the old parts that we will be replacing it is time to clean up the backing plate and prepare it for new brake shoes.
The first thing you want to inspect is the friction points where the shoes ride up against the backing plate.
You should see at least 4 or 6 small bumps on the backing plate about a half inch high. This is the point of contact and it can sometimes see some aggressive friction. This surface must be free of any groves If you do see a grove then you will need to use a grinder to make the surface flat. If the grove is through the backing plate pad then you may need to replace your backing plate.
Use a wire brush or grinder and clean the friction points.
Clean the bottom pin where the end of the shoe will contact and be aligned.
Wire brush the ends of your wheel cylinder pins carefully to remove rust where the shoe end will rest at the top.
Since you have your wire brush out you want to clean the groove that goes around the edge of the mounting plate. This is where the drum will be inserted. Although this groove should not see any friction from the drum it can rust and cause noise from rubbing making you think there is a problem with your brakes when really there isn’t … its just rusty.
Also brush down the surface of the backing plate as best you can and anything else that is rusty.
At this point you can wash down the surface with brake cleaner.
I suggest that you also apply some brake caliper rated 800F or at least engine enamel rated 500F gloss black paint to the surface you just cleaned to protect it from rusting.
Go ahead and paint the contact point nubs you cleaned but later they will receive grease before you install the pads.
Greasing the Backing Plate
Once the paint on the backing plate is dry you can apply grease to all of the friction points.
Only a small amount of grease is necessary to protect the surface from rust and to provide good movement. I normally will use one of the small straws that is found on the end of a can of cleaner to apply just a small amount and not a brush which will get grease in areas you don’t need.
In addition to the four shoe contact points you will need to apply grease to the bottom pin where the end of the shoe makes contact and to the ends of the wheel cylinders.
Preparing New Brake Shoes For Installation
Once you have cleaned up your backing plate you can begin to prepare the new brake pad shoes for installation. It is very important that you work cleanly from this point on and important that you wash your hands or gloves of all grease. Any oils or grease that get on your pad surfaces will embed into the pad an reduce your stopping ability and cause uneven braking and wearing of your brakes. Even natural oils on your hands can cause problems and you will in the final cleanup need to wash down your pads and drums with brake cleaner before final assembly.
In this final preparation you will be removing the emergency brake lever from the old pad shoe and installing it on the new shoe.
Our manufacturer uses identical front and back shoes but some manufacturers will use a shoe that is different front to back having different mounting points and shapes. If this is true for your vehicle you want to match your sets and look for a LR left rear or similar marking on all the shoes to help in the selection and positioning of each pad.
Reinstalling the Emergency Brake Lever
Remove the C-Clip retainer on the mounting pin with a screwdriver by wedging the driver in the opening of the clip and rotating it to spread the clip open.
When the old clip is removed you will most likely need to tap out the retaining pin if it is not a part of the shoe. Tap the pin free and make sure that you do not lose the small washer that is installed below the clip. Most hardware kits will not include a new washer but they will include a new clip since they can not be reused.
Insert the pin into the new shoe making sure to select the correct hole.
Apply a very small amount of grease between the shoe surface and the emergency brake lever to allow for good movement but not so much that it will get on the shoes or attract dust.
Remember that you rotated the shoe to remove it from the emergency brake cable so the emergency brake lever will need to be installed on the top hole with the lever positioned behind the brake shoe.
Install the new C-Clip on the pin to retain the emergency brake lever using needle nosed pliers to close the clip around the pin. You only get one shot so make sure everything is in the right position before you compress the clip.
Test the movement of the emergency brake lever by pushing it back and forth then wipe the area with a clean paper towel to remove any extra grease.
Mount the Rear Brake Shoe
Once the emergency brake lever is attached to the rear pad you can install the rear shoe. Mount it to the backing plate with a new pin and clip if you have purchased a hardware kit.
Start by attaching the emergency brake lever to the emergency brake cable. Compress the spring, insert the cable end into the notch and then rotate the shoe into place against the backing plate.
Make sure that you do not force the wheel cylinder piston too far into the wheel cylinder chamber when you position the top of the shoe in the opening or it will force the opposite side piston out of the wheel cylinder and you will need to bleed your brakes. If this happens you want to read the Wheel Cylinder HowTo on how to position the pistons and spring then clean the area with brake cleaner.
If the shoe pad got brake fluid on it you will need to wash it down thoroughly with brake cleaner to remove all of it.
Servicing the Self Adjuster Rod
The self adjuster is made of three parts and a washer. All of the parts must move freely to allow the self adjuster to work properly.
Disassemble the self adjuster and using a brass not steel wire brush clean the threads of any rust or dirt.
If there is rust on the outside of the self adjuster you should wire brush that clean and the pin and hole on the opposite side.
Once all of the parts are clean you will need to lubricate the threads using brake lube.
You should wipe any extra grease from the adjuster and then paint the outside with caliper paint if needed.
You should also grease the fork ends where they will be inserted into the brake shoes. Us only a small amount of grease to allow free movement without the risk of attracting lots of brake dust.
The self adjuster rod should be inserted into the rear shoe before installing the front shoe.
Make sure that you have correctly inserted the fork with the shortened end into the rear shoe. The short side should be to the back of the shoe to allow the emergency brake lever room to move.
Since the grease will hold the self adjuster rod together there should be no problem allowing it to hang in place until you are ready to install the front shoe.
Applying the Self Adjuster Clip and Spring
On the front shoe you will need to install the self adjuster clip and spring to the shoe before you mount the shoe to the backing plate.
Apply a small amount of grease on the pin where it inserts into the brake shoe.
Install the brake spring to the clip and the shoe. Note that this will probably move the clip away from the shoe a bit but it should hold in place as you mount the shoe.
Mounting the Front Brake Shoe
You can now mount the front shoe in place along with the self adjuster clip and spring already attached.
When positioning the shoe it is very important to pay close attention to the tab on the top of the self adjuster clip.
This tab must be inserted behind the fork of the self adjuster rod.
This is where things get a little tricky.
Put your finger on the clip to force it against the brake shoe then apply the brake shoe to the backing plate while guiding the self adjuster fork into the front shoe mounting notch.
Once the self adjuster is in the notch with the self adjuster tab inside the fork slide the brake mounting pin in from behind and through the mounting clip.
Force the mounting clip down and rotate the pin to attach the new shoe to the backing plate securely.
Installing the Springs
Now you can install the top and bottom springs to complete the reattachment of all of the parts.
The bottom spring is the easiest to install and it will hold the shoes together as you apply the top spring so start with the bottom spring.
Insert one side of the spring in the shoe making sure to position it behind the bottom mounting pin plate and then using needle nose locking vice grips pull the other side into the hole on the opposite shoe.
Installing the top spring.
Once you have the bottom spring in place you should center the shoes and make sure that nothing has moved out of place at the top.
Compare the new spring that you will be installing to the one that you took off.
Make sure that the flat half inch section over the self adjuster wheel is to the top and out of the way.
Apply the spring to one side and then pull it into place using your locking vice grips.
Adjusting the Brakes
Since the shoes you installed are larger in the opening it is important to adjust the self adjuster wheel before you install your drum.
Using a small screw driver you should be able to access the adjusting wheel through an access hole on the axel plate.
Turn the wheel clockwise or counter clockwise to open or close the self adjuster pin as needed.
Your brake drum should fit very snugly over your new shoes without binding.
Meaning you should just barely be able to get the drum on with easy pressure and still be able to get the drum back off.
If the drum was not cut you may find that its out of shape and will bind on the new shoes.
Final Note
Making the final adjustment to your drum brakes is something you learn with experience. If you find that when you apply the parking / emergency brake that you have a lot of play. Or if you have a lot of play in your peddle you may need to bring your vehicle to a shop and ask them to make the adjustment for you.
For an experienced technician this will most likely not even require removing the back wheels. They can access the adjuster wheel from the access hole in the backing plate an tighten the rear brakes as needed.
However since you just did a brake job you might ask them to review your work.
It should not cost more then 15 mins labor or free.
Servicing and Repairing your cars braking system is not the most difficult job you can accomplish on your vehicle but it does take proper care, planning and a few good hand tools.
If you have any doubts about performing this job then bring the work to a professional. Often the cost of doing the work yourself vs a guaranteed job is not extremely different but it could save you enough money to buy more parts and do a better job if you can perform the work yourself.