If your brakes are getting stiff, not responding, or sinking, the master cylinder is a good culprit. That’s especially true if you keep having to change brake fluid or if the brake pedal actually feels spongy.
The good news is the cylinder is relatively easy to change, although you’ll have to bleed the brakes after.
The average cost of replacing a master cylinder is $250-$700, with an average of about $380 for the full job. That works out to $50-$170 in parts and 1-2 hours of labor, including the brake bleed. However, the cost of parts does vary. In addition, a bad master cylinder can ruin your brakes and pads, so you might have to replace those too.
The table below shows a quick price comparison of master cylinder replacement cost estimates from reputable suppliers:
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How Much Does Master Cylinder Replacement Cost?*
The largest cost factor for replacing a master cylinder is always the make and model of your vehicle. That’s because your engine will need different parts, heat resistance, etc.
In addition, your mechanic will spend more time replacing the part on smaller or more tightly built engines.
The following chart shows cost estimates for replacing the brake master cylinder in different vehicles to give you a rough idea of how much that changes from car to car.
|Vehicle||Master Cylinder Cost||Labor Cost|
*Note: Prices are estimates and were correct at the time of writing (April 2022). Cost estimates may have changed since, our figures should be used as a starting point for your own research.
Master Cylinder Replacement Price Factors
If you’re replacing a master cylinder, the most important cost factor is the make and model of your vehicle.
However, the following price factors will impact your final bill.
Part Type and Condition
Master cylinders are made up of three primary components: reservoir, piston, and spring. Here, you can choose to purchase just part of the system or a full replacement.
In addition, you might need a single or a dual reservoir. Here, single reservoir systems pressure both the front and back brakes from a single reservoir.
Dual reservoir systems use separate tanks for each brake system, offering an added line of security. These factors all impact costs.
In addition, you’ll want to look at the brand and condition of the part.
A brand new, Original Equipment Manufacturer master cylinder will cost anywhere from $160 for a Ford part to over $1,000 for a Lexus part.
Alternatively, you can choose made-to-fit parts to reduce that cost. These are designed to fit into any vehicle with those exact dimensions and specifications.
A universal part is one that is made to fit into as many vehicles as possible, which is even cheaper. However, you may see some slight differences in fit.
Finally, you can always choose a secondhand or remanufactured part to reduce costs further. You should normally decide this based on factors like the age of your vehicle, the condition of the part, total budget, etc.
Unfortunately, not all mechanics will install secondhand parts.
Bleeding the Brakes
Anytime you remove the master cylinder, you’ll have to bleed the brakes. That can add significantly to the total cost of the job.
In addition, you might have to pay for new brake fluid. Here, some vehicles require a diagnostic check and scan to bleed. In other cases, you can do the work at home if you prefer.
In either case, it usually accounts for as much as $100 of total costs.
Other Parts Needing Replacement
A bad master cylinder usually isn’t noticeable until things start to go wrong.
Here, you might notice that your brake pads are wearing unevenly, that your brake fluid is discolored, or that you’re leaking brake fluid. That might necessitate a full brake fluid replacement.
You might also have to replace the brake pads or even replace the brake discs. Therefore, your total job could be quite a bit more expensive, because you have to replace more than just the master cylinder.
Cost of Labor
Labor is always going to be one of the largest costs in replacing a brake master cylinder – unless you’re driving a luxury car where the cost of parts runs over $1,000.
Here, the largest factor in the cost is that while you will spend 30-60 minutes taking the old master cylinder out and replacing it, you’ll spend another 30-60 minutes bleeding the brakes.
So, you’ll pay for 1-2 hours of your mechanic’s time at a minimum.
In most of the country, that will average out to around $100-$250. Here, you’ll pay an average of $60 per hour + a shop fee.
However, mechanic’s rates can range from $15-$205+ per hour, so the final rate really depends on where you go.
5 Symptoms of a Bad Master Cylinder
If your master cylinder is going out, you’ll probably notice because the brakes are having trouble. However, symptoms can vary depending on what’s going wrong and why.
These 5 symptoms of a bad master cylinder are the best ways to spot a problem.
1. Fluid Leaks
Fluid leaks can come from any part of the brake system, but they are very often from the master cylinder.
You might have issues with the seals inside the cylinder, if the reservoir is loose, or if the reservoir itself is cracked or otherwise damaged. Here, it’s easy to inspect for physical damage.
You can also check to see if you have physical fluid leaking around the master cylinder itself. And, when you take it out, one good tell for the seals is that they should never have fluid on them. If they do, the master cylinder has a seal leak.
2. Spongy or Soft Brake Pedal
If your brake pedal is soft, spongey, or rises too slowly, it might be a master cylinder issue. Here, the issue might be that the brake fluid is low.
It might also be that brake fluid has damaged the diaphragm in the brake booster – meaning you’ll have to replace that too.
In fact, if you do have sealant leaks, your mechanic might insist on replacing both parts at once, which can significantly add to the total cost of the job.
3. Discolored Brake Fluid
If you notice your brake fluid has changed color, it usually means there’s seepage into the system. However, this might not stem from the master cylinder.
Instead, you could have a seal leak or a line issue somewhere else. If humidity gets into the system, brake fluid will discolor.
However, the master cylinder is a very likely culprit and you should inspect it if you notice brake fluid is discolored.
4. Drifting When Braking
Most master cylinders use a dual system of hydraulic brake circuits to control each side of the vehicle.
Therefore, you’ll normally see uneven brake performance on each side of the vehicle when it starts to fail.
You might even drift to the left or right when braking, because one side is performing better than the other.
5. Uneven Brake Wear
Uneven brake wear happens for the same reason as above. However, damage to brake pads and discs can occur even when drift is so slight you don’t notice it when driving.
So, if you notice uneven brake pad wear during a brake inspection, it’s a good idea to check the master cylinder. However, this symptom can stem from other issues with the suspension and even the steering.
10 Steps: How to Change a Master Cylinder
If you have to replace your master cylinder, you can do so yourself. However, you will need a set of flare wrenches to get the brake lines off.
Otherwise, you don’t need anything special, and you can likely easily do the work yourself in about an hour. However, you will have to bleed the brake lines after, which you might not be able to do without a scan.
Things You’ll Need:
- Disposable gloves
- Drain pan
- Flare wrenches for brake line
- Ratchet and socket set
- Crescent wrenches
- Replacement master cylinder
- Brake cleaner
- Paper towels/shop towels
Replacing Your Master Cylinder
Replacing your master cylinder is relatively easy and you can do so from the hood of your car.
However, you might still want to practice basic safety precautions and take the key out of your ignition and then disconnect the battery from the negative post.
In addition, it’s a good idea to chock the back wheels.
- Release the pressure on the vacuum system by pumping the brake pedal with the engine off. Stop when the pedal gets stiff.
- Look for the master cylinder on the driver’s side, near the back. It should be almost against the back wall of the engine.
- Remove the electrical connection to the cylinder by depressing the pin; take it off and set the clip aside.
- Remove the mounting nuts with a ratchet and socket.
- Place paper towels around the engine and use the flare wrench to undo the brake lines. Use your fingers (while wearing gloves) to stopper the ends as you move them and slide the entire master cylinder into a drain pan.
- If you spilled brake fluid, especially on paint, rinse it off with water immediately.
- Inspect the seal on the master cylinder. If it’s covered with fluid, you likely have to replace the brake booster as well.
- Use brake cleaner to clean the mounting surface.
- Insert the new master cylinder.
- Re-attach everything in the opposite order of removing the cylinder.
Once you have everything back in place, you will have to bleed the brakes. To do so, you’ll have to check your vehicle to ensure you have the right type of brake fluid.
You might also have to take the wheels off to do the work. And, you’ll need a siphon or a hand pump to properly bleed the brakes.
Here, it may be a good idea to take your car to a mechanic. Most shops offer cheap rates on brake bleeds.
However, with a small pump or turkey baster, you can do so yourself. Make sure you check your vehicle’s manual to see which order you should bleed your brakes.
However, it’s most often furthest to closest or passenger rear-driver rear-passenger-driver. You will need an assistant to bleed the brakes.
If you still have questions about replacing your master cylinder, these answers should help.
How long does it take to replace a master cylinder?
In most cases, your mechanic will charge you for 1-2 hours of work for the job, including bleeding the brakes. If you’re doing the work for yourself the first time, you can expect it to take a bit longer.
However, if you know what you’re doing, there’s no reason why you can’t have your master cylinder fully replaced in under an hour.
Can you drive with a bad master cylinder?
It can be very dangerous to drive your vehicle with a bad master cylinder. That’s because the brakes could fail, you might not be able to stop, and you could drift when you do stop.
It’s likely safe enough to drive slowly to a mechanic but driving long-term is very unsafe.
How often should master cylinder be replaced?
Most master cylinders will last anywhere from 150,000 miles to the lifetime of the car. Here, the seals and the reservoir are weak spots because both can break.
If so, you can often simply replace the reservoir. However, if the seal is damaged, you’ll have to replace the full cylinder.
What does it mean when your brakes go to the floor?
If your brakes go to the floor, you’re probably low on brake fluid. However, you could have other vacuum issues which you might want to check.
Whatever the issue is, you have a serious problem and you should get it fixed.
Replacing a master cylinder will normally cost around $500 including labor and bleeding the brakes. If you do the work yourself, you can save money.
In addition, you can always save money by choosing aftermarket or even remanufactured parts.
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