Your wheel cylinder plays a vital role in your car’s drum braking system. And while it isn’t known to fail often, when it does, you need to get it fixed ASAP.
But why does your wheel cylinder fail in the first place?
And how is a wheel cylinder replacement performed?
We’ll answer both of those questions in this article. We’ll also go through the tell-tale signs of a faulty wheel cylinder and cover some related FAQs.
This Article Contains
- Why Would You Need a Wheel Cylinder Replacement?
- How Does a Mechanic Replace the Wheel Cylinder?
- How Much Does a Wheel Cylinder Replacement Cost?
- 8 Brake Wheel Cylinder FAQs
- What Is a Brake Wheel Cylinder?
- Are Rear Brakes Always Drum Brakes?
- Does the Wheel Cylinder Wear Out Like Brake Shoes?
- What Are the Symptoms of a Bad Wheel Cylinder?
- Why Is My Wheel Cylinder Leaking?
- When Should I Get My Wheel Cylinders Checked?
- What Should I Look For In a New Wheel Cylinder?
- Can a Wheel Cylinder Be Rebuilt?
Let’s get started.
Why Would You Need a Wheel Cylinder Replacement?
Unlike a brake shoe or brake pad (in disc brakes), the brake wheel cylinders aren’t designed to wear out. However, your vehicle’s rear brake cylinders have moving parts that are subject to wear and tear over time.
Here are some typical ways that the wheel cylinder fails:
- The rubber seals become brittle and break, resulting in a brake fluid leak
- The pistons wear down, can’t be adequately sealed, and start leaking brake fluid
- A piston gets stuck in a corroded cylinder bore
- A piston slips out of the cylinder bore when there’s too much gap between a worn brake drum
- An old cylinder body can crack and leak brake fluid
If you have a bad brake wheel cylinder, your drum brake won’t work.
That’s why, if you spot any of these symptoms, you’d want a mechanic to perform a wheel cylinder inspection ASAP.
Curious about what your mechanic will do once you bring your car to an auto repair shop?
How Does a Mechanic Replace the Wheel Cylinder?
Before we divulge the brake job details, note that wheel cylinders are always replaced in pairs, even if one doesn’t have problems.
Why?
Wheel cylinders don’t fail often, but if one goes bad, the matching pair is likely not too far behind it in wear and tear. That’s why it’s always better to be proactive and replace both.
To begin the replacement, your mechanic will need several items:
- A mechanic’s tool set that includes a line wrench, ratchet, flat screwdriver, etc.
- Protective gloves and eyewear
- Brake cleaner
- A new wheel cylinder
- Fresh brake fluid
Here’s an overview of the bad brake wheel cylinder replacement process.
Your auto repair mechanic will:
- Raise the vehicle on a hydraulic lift or jack stand.
- Remove the rear wheels.
- Uncover the drum and inspect the drum brake interior.
- Remove the retainer springs with vice grips from the wheel cylinder and brake shoes.
- Remove the brake line (brake pipe) from the wheel cylinder with a line wrench. (Brake fluid will spill from the open brake line, so a vacuum rubber cap may be used to prevent too much brake fluid loss from the brake master cylinder).
- Unscrew each wheel cylinder bolt from the backing plate.
- Unmount the old brake cylinder from the backing plate.
- Clean the drum brake surface and components of grime and brake dust with brake cleaner.
- Resurface the brake drum if needed.
- Reinstall the brake shoes (or new ones if needed).
- Install the new cylinder onto the backplate and secure each wheel cylinder bolt.
- After fitting the new cylinder, reattach the brake line, retainer springs, plungers for brake shoes, and so on. (A mechanic should ensure not to twist the brake pipe too tight while fitting the brake line connection to the wheel cylinder, as doing so may break the line.)
- Bleed the brakes through the bleeder valve and top up the brake fluid reservoir.
- Reattach the wheels and ensure each lug bolt is tightened.
- Lower the vehicle and readjust the brake shoes fitting against the brake drum.
Note: Your drum brakes must always be adjusted after a wheel cylinder or brake shoe replacement. This ensures the brake shoes sit at an optimum distance from the brake drum.
Wondering how much this brake job will cost?
How Much Does a Wheel Cylinder Replacement Cost?
The cost will vary based on the make and model of the vehicle, labor charges, and your location. But in general, replacing brake wheel cylinders will average between $200-$350.
To give you an idea, here are some examples of average dealer prices:
| Vehicle Model | Average Dealer Price |
|---|---|
| 2015 Volvo S80 | $212 |
| 2013 GMC Savana 2500 | $310 |
| 2007 Volkswagen Jetta | $251 |
| 2015 Cadillac CTS | $190 |
Now that you know how a brake wheel cylinder replacement is done and what it costs, let’s cover some FAQs.
8 Brake Wheel Cylinder FAQs
We’ll look at some answers to queries you may have about wheel cylinders:
1. What Is a Brake Wheel Cylinder?
The wheel cylinder is a metal cylinder usually made of cast iron or aluminum.
Inside the wheel cylinder bore, you’ll find:
- A piston, located at each end of the cylinder bore
- Internal piston seals shaped like cups
- A spring between the pistons holding the seals in place
- A rubber dust boot covering the wheel cylinder piston at each end
Two more important components are located at the center of the brake wheel cylinders.
They are:
- An inlet port for brake fluid intake
- A bleeder screw (or bleeder valve) for bleeding air from the brake fluid
How does the wheel cylinder work?
Each wheel cylinder piston is attached to a shaft connected to a brake shoe. When you step on the brake pedal, hydraulic pressure from the brake master cylinder pushes the pistons outwards, bringing the brake shoes into contact with the rotating brake drum, stopping your wheels.
2. Are Rear Brakes Always Drum Brakes?
No.
A vehicle can have disc brakes on its rear axles too, but they’re a bit more expensive than drum brakes. That’s why you’ll usually find a drum brake on the rear brake of economy cars or light trucks, as they’re cost-effective and a reliable option for rear braking.
Note: Because drum brakes are usually at the rear, the brake wheel cylinder is often referred to as the rear wheel cylinder.
3. Does the Wheel Cylinder Wear Out Like Brake Shoes?
No, the wheel cylinder isn’t designed to wear out like a brake shoe or brake pad.
However, its seals can break and leak over time.
It’s always advisable to replace the wheel cylinder during a brake shoe replacement, as this will avoid additional labor and workshop time.
Additionally, new brake shoes are thicker, so pushing them can create extra stress on an old wheel cylinder — causing it to fail and necessitating a replacement anyway.
4. What Are the Symptoms of a Bad Wheel Cylinder?
Here are some common symptoms accompanying a bad wheel cylinder:
A. A Spongy or Sinking Brake Pedal
A brake pedal that feels soft or sinks to the vehicle floor indicates a drop in hydraulic pressure. You’ll also notice poor brake response while braking. This can result from a brake fluid leak in the brake system — like a broken wheel cylinder seal.
B. Noisy Rear Brakes
Loud grinding noises can come from brake shoes that aren’t receiving even pressure from a faulty wheel cylinder.
C. Brake Fluid Leak
Any brake fluid leaking on the rear wheels or pooling near them can point to a brake wheel cylinder leak.
5. Why Is My Wheel Cylinder Leaking?
Each time you hit the brake pedal, the master cylinder transfers hydraulic pressure to your brake wheel cylinders via brake fluid.
This brake fluid, over time, can absorb moisture from the air and corrode the cylinder bore, leaving holes in it. The inner rubber parts (like the dust boot) can also wear out and allow the brake fluid to travel past the pistons, resulting in a wheel cylinder leak.
Is there a way to prevent it?
Getting scheduled service and maintenance (including a wheel cylinder inspection) and replacing your brake fluid regularly can prolong the life of your rear wheel cylinder and the entire braking system.
6. When Should I Get My Wheel Cylinders Checked?
Ideally, you should get your wheel cylinders checked at least once a year or whenever the rear wheels are off. Also, get them checked if the brake warning lights come on — indicating a fault in the brake system.
7. What Should I Look For In a New Wheel Cylinder?
If you’re going to purchase a wheel cylinder yourself, there are certain things you should look out for.
The wheel cylinder should:
- Meet SAE J431-GG3000 standards for manufacturing and quality assurance
- Have a cylinder bore finish of 5-25 RA microinches to ensure a smooth bore surface
- Have a bleeder screw that is corrosion resistant
- Be of a metal that matches your OEM wheel cylinder
- Be compatible with your specific vehicle make and model
- Have a lifetime warranty
To save yourself the hassle, let your mechanic figure out which brake wheel cylinder is right for your vehicle.
8. Can a Wheel Cylinder Be Rebuilt?
Yes, wheel cylinders can be rebuilt instead of replaced.
However, most professional technicians will recommend a brake wheel cylinder replacement as rebuilding takes time, and there’s always a risk of additional problems.
The material of the brake cylinder also drives this decision. An aluminum wheel cylinder must always be replaced, as honing it (to smoothen the bore) will remove the anodized coating that keeps it corrosion-free.
Final Thoughts
The brake wheel cylinder is a relatively simple component, but replacing it isn’t a straightforward task. Many pieces need to be removed and reinstalled correctly, which requires some expertise.
Your best bet is to secure the services of a trustworthy mechanic who’ll give you a reliable overview of your drum brakes, replace your wheel cylinder, and adjust your brakes correctly.
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For an accurate estimate of the cost of brake wheel cylinder replacement and repairs, fill out this online form.