We don’t need to tell you how important your brakes are. They are made up of a small group of parts, all of which serve fairly simple purposes. The technology or mechanism behind these components is not that complex either. And that’s all the more reason to stay on top of your brake system maintenance. Let’s not forget that they are the single most important safety feature on any car.
Besides replacing the brake pads and brake rotors, the system also requires bleeding from time to time. This is usually carried out along with a brake fluid flush. However, what if you can’t bleed the brakes on your car? There are instances where people have had trouble bleeding their brakes, resulting in a constantly mushy pedal. As it turns out, several issues can lead to this condition, and today we’ll go over the most common ones.
On a similar note, it’s quite common to incorrectly bleed brakes and end up having problems that can be downright dangerous. That’s why we’ll first begin by discussing the proper way to bleed brakes.
Why Do You Need to Bleed Brakes on Your Car?
Every time you drive a car and step on the brake pedal, you can feel the brake fluid in the system doing its job. Each time you step on the pedal, the fluid is pressurized. The degree of pressure in the braking system is dictated by how far you push the pedal. It’s the brake master cylinder that pressurizes the brake fluid. The fluid then gathers the energy needed to work the calipers which then push the pads onto the rotors to decrease the car’s speed.
In most cars, the service interval for this vital fluid is lengthy. Usually, brake fluid doesn’t need to be changed for two years. However, it doesn’t last forever and begins to lose its effectiveness after a while. The issue with brake fluid is its hygroscopic nature — the natural attraction to moisture. Over time the fluid gathers water and changes color, which in turn reduces its boiling point since the boiling point of water is 211.95 °F or 100 °C. As a result, you’ll lose some of the braking performance as your brakes become hotter. That’s why it’s essential to replace the brake fluid as recommended by the manufacturer. Use only quality brake fluid as well. Here’s a selection from some of the best manufacturers out there.
Every time the brake fluid is replaced, you need to bleed the brakes on your car. This is necessary for two reasons. For one, filling the system with fresh fluid will introduce little air pockets. This trapped air has to be removed as it can reduce the braking potential of a vehicle significantly. The second reason is basically to make sure you don’t have any of the old fluid still present in the system. The brake lines run in the direction of all four wheels and the only way to make sure old brake fluid is out of these narrow pipes is by a thorough bleeding procedure.
What Are the Different Ways to Bleed Brakes?
There are several different ways to bleed your brakes, some simpler than others. We list out the five different ways below but recommend sticking to the way recommended by your car’s manufacturer.
- Vacuum pump method
- Pump and hold method
- Gravity bleed method
- Pressure pump method
That said, what all these methods have in common is the need to add fresh brake fluid into the master cylinder after you bleed each wheel. That way you won’t run the master cylinder dry, which can very well be the cause behind your troubles with bleeding the brakes.
Vacuum Pump Method
One of the most popular ways to bleed brakes is by using a vacuum. To bleed brakes using this method, you will need a vacuum pump. This pump comes with a short tube that fits snugly around the bleeder valve on your brake caliper. You then use the pump to pull the fluid out until there are no air bubbles present in the system.
Pump and Hold Method
The pump-and-hold method, as its name suggests, requires the brake pedal to be pushed while the bleeding is carried out. This is difficult to do by a single individual as the procedure requires the pedal to be pressed while the bleeder valves are opened. Then the bleeder valve has to be closed before the pedal is released to ensure air doesn’t make its way into the system. Repeat until you see no bubbles.
Gravity Bleeding Method
Another common way to bleed brakes is by the gravity bleeding method. This method is the simplest way to do this and can be carried out without the help of anyone else. What one has to make sure of is that the master cylinder is situated above the wheels, which is the case in most cars.
With the fresh fluid in, you have to undo the bleeder valves to allow gravity to do its thing. Keep in mind, it can take more than an hour to get all the air bubbles out, and even then it might not be as effective as the other methods mentioned here.
Pressure Pump Method
The pressure pump is the most advanced way to bleed brakes. You’re essentially attaching a pressure pump to the master cylinder. Like every other method, this system also makes use of the bleeder valves as they have to be left open for the air to clear. These pumps also ensure that the brake fluid reservoir is at the correct level.
How to Bleed Brakes Properly?
To bleed your brakes properly, you could use any of the methods mentioned above. However, it’s important to make sure it’s being done correctly. You do not want to end up with mushy and weak brakes.
The gravity method should be your last method as it requires a lot of time and patience to be done correctly. Moreover, stick to the recommended service interval for the brake fluid as it can vary significantly from car to car. Lastly, it’s a good idea to replace the brake fluid if it’s been sitting for 5 years even if the car hasn’t done the recommended miles.
Troubleshooting Failure to Bleed Brakes
If you are having trouble bleeding the brakes on your car, you want to start troubleshooting by ruling out possible reasons.
Air In the Master Cylinder
One of the main causes of brake bleeding issues is air in the master cylinder. This happens when you either have a leak somewhere in or near the cylinder or when you fail to top off the fluid as you bleed the brakes. The problem now is that bleeding the master cylinder usually requires you to remove it and bleed it on a bench since you need to make sure that all 4 main brake lines are properly bled.
Contamination
If that’s not the case, and you are still having trouble bleeding the brakes, there’s likely a more serious problem. There’s a possibility of the system being contaminated with dirt and debris. If that’s the case, it’s possible that the system will need more than a flush to fix this problem as one of the lines or components could be severely clogged.
Contaminated brake fluid could have also corroded internal components. A component that could be affected by external contamination is the bleeder valve. This is exposed to mud and water in the wheel well which could cause it to rust to the point of failure.
Leaks
One of the most common causes of problems with bleeding brakes has to do with leaks. These leaks are usually caused by a rupture somewhere along the main brake line, commonly around fittings where rubber brake lines meet their metal counterparts.
If there is a leak in the hose, you’ll constantly have air entering the system every time you press the brake. Similarly, a leak from the calipers, especially one of the seals won’t allow you to bleed the brakes on your car properly.
Bad Master Cylinder
The master cylinder consists of a cylinder that moves back and forth allowing the brake fluid to be directed to each of the required lines. This cylinder also ensures that the lines have sufficient pressure and help the brakes work as they should.
When the master cylinder goes bad, the cylinder could seize and severely affect the braking system. You will need the replacement master cylinder before you can bleed the brakes on your car again. Check our selection of brake master cylinders for quality replacement options!
Damaged Proportioning Valve
If you are having trouble bleeding the rear brakes on your, it’s most likely due to a damaged proportioning valve. This valve manages and directs brake fluid to the rear brakes. When this valve goes bad, there will be little to no brake fluid being sent to the rear brakes.
The proportioning valve could go bad due to a few reasons, but the most common one is due to a blockage. This problem is best fixed by replacing the part.
Better Safe Than Sorry!
Flush the fluid and bleed the brakes on your car! Don’t overlook this essential piece of regular maintenance. Remember, bleeding the brakes properly is equally important as fresh fluid.
Flushing the fluid is also quite inexpensive. So, that leaves you with no reason to not replace the fluid and bleed brakes on your car. If you’re looking for quality brake components and brake fluids, head over to our shop section and check out our catalog. We stock some of the best brands from all around the world.
