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No fluid coming out when bleeding brakes can be scary, especially when you don’t know what causes the problem and how to fix it. It is also a sign that your brake fluid is leaking, just as bad as a fuel leak.
In this article, we’ll discuss why brake fluids won’t come out when they’re being bled. We’ll also suggest practical steps to solve the problem and answer a few questions on bleeding brakes.
JUMP TO TOPIC
- 1 Why Is There No Fluid Coming Out When Bleeding Brakes?
- 1.1 – A Blocked Brake Line Will Prevent the Free Flow of Fluid
- 1.2 – Air Bubbles Can Also Clog the Brake Lines
- 1.3 – A Broken Master Cylinder Affects Fluid Distribution
- 1.4 – Faulty Brake Calipers Will Obstruct Brake Bleeding
- 1.5 – A Cracked Brake Fluid Hose Can Leak Some of the Fluid
- 1.6 – A Broken Brake Proportioning Valve May Stop Bleeding
- 2 What Are Solutions to No Fluid Coming Out When Bleeding Brakes?
- 3 Why Is There No Fluid Coming Out When Trying to Push Back the Brake Piston?
- 4 Conclusion
Why Is There No Fluid Coming Out When Bleeding Brakes?
There is no fluid coming out when bleeding brakes because of a clogged brake line or bleed valve, air bubbles, or a faulty master cylinder. It also means the calipers could be faulty, the hoses have cracks, or a faulty proportioning valve might be the cause.
– A Blocked Brake Line Will Prevent the Free Flow of Fluid
Contaminants and debris inside the brake fluid are common as it hardly gets serviced. When these contaminants increase over time, they block the brake lines or valves during bleeding. This is why you have no fluid coming out of brake line when you try to bleed brakes.
– Air Bubbles Can Also Clog the Brake Lines
Air can get into the braking system during repairs and form bubbles, but more commonly, the bubbles of air form inside the liquid. The constituents of the brake fluid easily absorb water from the atmosphere. This water lowers the boiling point of the fluid and when the fluid is heated, the water in it becomes steam, which leaves air in the brake lines. That is why there’s no brake fluid to front brakes when bleeding.
This air reduces the efficiency of the braking system, giving it a mushy feel whenever you apply them, which can be dangerous. Air in the braking fluid increases the braking distance or won’t even let it brake at all, leading to road accidents.
– A Broken Master Cylinder Affects Fluid Distribution
The master cylinder’s job is to convert pressure applied on the brakes to hydraulic pressure by allowing brake fluid into the brake circuit. The master cylinder also controls the hydraulic pressure according to the mechanical force applied to the pedal. Thus, no fluid leaving master cylinder into the circuit means the cylinder it is damaged. Further damage to the master cylinder may cause it to leak, making the brake feel mushy.
When you apply the brakes in the vehicle, the brake pedal will go further down than usual while struggling to stop the vehicle. This can lead to road accidents as the braking system won’t function properly. Thus, you should report to the mechanic’s workshop immediately after you notice the symptoms of a damaged master cylinder.
– Faulty Brake Calipers Will Obstruct Brake Bleeding
The brake calipers will press the brake pads against the rotor to stop the wheel. They operate with the help of the hydraulic pressure applied to the pistons in the caliper. However, a leaking brake pedal will reduce the pressure necessary to stop the car and impede the brake fluid’s smooth flow during bleeding.
Don’t be surprised when a new brake caliper won’t bleed because it may have been contaminated before you fixed it. When you notice that your pads are spongy or mush, allow the mechanic to check whether to brake calipers are in good condition.
– A Cracked Brake Fluid Hose Can Leak Some of the Fluid
A brake fluid hose transports the fluid from the master cylinder to the caliper or the wheel cylinder to help bring the vehicle to a stop. When there’s a crack in the hose, some of the brake fluid seeps through the crack, reducing the fluid pressure in the system. If this happens, you’ll note that the brake fluid runs out much quicker than expected. Also, when you try to bleed brakes so you can refill them, you might not see any fluid coming out.
Some of this fluid may gather under your car and form puddles when your car is stationary. You may even see traces of brake fluid around the hose when you remove them. A cracked hose affects your vehicle’s braking performance; thus, you should fix it as soon as it rears its head.
– A Broken Brake Proportioning Valve May Stop Bleeding
A proportional valve reduces the pressure on the rear brakes when pressing the pedal down. Doing this prevents wheel locking, helping the vehicle to stop safely and efficiently. Brake proportional valves come alive when the fluid pressure builds up in the brake system after you’ve applied the brakes.
Then, the valve plunger opens for the brake fluid to pass through. Therefore, a broken brake proportioning valve won’t allow the liquid to come out during the bleeding process. That is why there’s no brake fluid to rear brakes when bleeding.
What Are Solutions to No Fluid Coming Out When Bleeding Brakes?
The solutions to no brake fluid coming out when bleeding brakes include using a brake cleaner to remove all the debris and cleaning the caliper with a rust remover. You can also use an air compressor to clear debris from congested brake lines and replace cracked hoses.
– Removing Contaminants From a Blocked Brake Valve
To be sure the fault is from a blocked brake valve, remove it from the caliper to see if some brake fluid will flow out. When fluid flows out of it, it means it is clogged and requires some cleansing.
The tools required to complete this job are a brake cleaner, a set of wrenches and a small pipe-cleaning brush. Spray some of the brake cleaner into the valve from both ends and clean the valve with a brush.
Keep repeating the process until you remove all the debris from the brake valve. If this process doesn’t work, try soaking the valve in brake cleaner for about 25 minutes. Then remove it and clean the inside with either a metal pick or a small toothbrush.
– Cleaning a Blocked Brake Caliper With an Air Compressor
No brake fluid to right front caliper means the caliper is blocked and needs decongestion. To do this job, you’ll need WD-40, a set of wrenches and an air compressor. First, remove the brake hose and spray the WD-40 on the metal pipe that attaches the hose to the end of the caliper. Allow the WD-40 to sit for some time before wiping it clean to remove the rust or dirt that might have settled on it.
Now, remove the metal pipe and check if you see oil flowing from it. If you see oil coming out, use the air compressor to blow some air into the caliper; this action should clear any debris inside it. Also, remember to unscrew the bleeder valve to allow more airflow through the caliper.
– Replacing a Broken Master Cylinder
If the seals in the master cylinder are broken, you can repair them. However, if the cylinder is broken, it needs replacement. First, draw out the brake fluid from its reservoir and locate the master cylinder directly underneath it. Next, remove the brake fluid sensor and the brake fluid lines and clean any spilled fluid with a towel.
Now, unscrew the bolts used in mounting the master cylinder, remove the old cylinder and replace it with a new one. Return the bolts to their sockets and tighten them to secure the device. Pour some brake fluid into the reservoir and allow some to flow through the brake pipe holes. The next step is to remove excess air from the cylinder by allowing someone to step on the brakes a few times.
After removing excess air, reconnect the brake fluid lines and the brake fluid sensor. Now, bleed the new master cylinder and take out the front wheel that is far from the hub. Next, bleed the brakes as well to ensure it works well.
– Replacing Cracked Brake Fluid Hoses
When you find out a cracked hose is the reason the fluid brake won’t come out when bleeding your brakes, it’s time to replace it. To remove the old hose, use an appropriate socket wrench to unfasten the bolts at both ends of the hose.
You can clamp the end of the hose to prevent the fluid from flowing out and then remove the hose from the car. Now, install the new hose by carefully threading one end onto the rigid steel line before attaching the other end to the caliper. Finally, ensure all the seals are in place to prevent any leakage after installation, and fasten the bolts at both ends of the hose.
– Installing a New Brake Proportioning Valve
First, park your vehicle on a level surface and clamp the wheels to prevent sudden movements that might harm you. Next, use jack lifts to help your vehicle’s wheels off the ground to get access to its underside. Now, open the car’s hood and detach the master cylinder’s cap and remove the brake fluid with a vampire pump. Locate the brake proportioning valve, place a drain pan under it, and detach the intake and the exhaust lines from it.
Unscrew the bolts used in supporting the valve before removing it from the vehicle. Install the new valve, place the bolts back in their sockets and tighten them. Attach the intake and exhaust lines you removed earlier and pour brake fluid into the master cylinder. Now, bleed the brakes with the help of another person to get rid of air in the system. Next, fill the master cylinder with brake fluid and step on the pedal several times until it is firm.
Ensure you check the entire system for leaks before closing the hood of the car. You can then remove the jack stands, lower the vehicle and remove the clamps on the wheels.
Why Is There No Fluid Coming Out When Trying to Push Back the Brake Piston?
It can be alarming when you want to change brake fluid but nothing comes out.
Here are some reasons why that happens and possible solutions to them:
- A congested brake line will prevent the liquid from flowing out during bleeding, and the best solution is to clear all the debris in it.
- Also, bubbles of air inside the brake lines will obstruct the bleeding process and the only way to solve this problem is to get the air out through bleeding.
- Broken master cylinders and brake proportioning valves can stop brake fluid from flowing and will need replacement if you want the problem to go away.
- A cracked brake fluid hose will cause the fluid to leak and will have to be replaced to ensure a complete bleeding process.
- Faulty calipers may also stop the fluid from coming out, making the brake pedals mushy or spongy.
Installing new parts of the braking system can be a bit tricky; therefore, we’ll advise you to allow a mechanic to do it for you if you’re new to these things.
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