How to Bleed Master Cylinder Without Bench Bleeding

Ask anyone with a car; they don’t take pleasure in bleeding the master cylinder of their car. Why? Because this is a tedious procedure. Unfortunately, 5% of the accidents happen due to brake failure. Not bleeding the master cylinder causes brake failure! Do you know how to bleed the master cylinder without bench bleeding? Or with bench bleeding?

Don’t worry if your answer is no. Hopefully, we are going to take you out of the unfortunate 5%. 

In this article, we will show you the process of bleeding your master cylinder without bench bleeding. What if you don’t have enough time to bleed without bench bleeding? Don’t worry; we will teach you bench bleeding also.

Why do you have to bleed the master cylinder? 

Bleeding the master cylinder has become significant because of the hydraulic braking system. It means the removal of air out of your master cylinder.

Why can you not neglect air in your braking system? Because the air will not let your brakes function correctly. Air in your master cylinder will not vanish automatically.

Brake fluids in your system will compress easily by applying pressure. But you can’t compress air easily. That’s why your brake will need more pressure to work properly if there’s air in it.

Air in master cylinder symptoms 

These are some of the symptoms that mean the existence of air in your master cylinder:

  • Press down your brake pedal. If it feels kind of spongy, then you have air in your braking system.
  • Less effective brakes mean that you have air in the master cylinder.
  • A loose or depressed brake pedal indicates air in the braking fluids.

Any of these symptoms prove the existence of air in your master cylinder. What’s the solution? Simple, get the air out of it.

How? Here’s how.

How to bleed brakes by yourself?

For bench bleeding, you will need a helper. But what if you don’t have someone to help right now?

Let us tell you how to bleed brakes by yourself. We will show your three easy and effective techniques. These techniques will let you bleed your brakes all by yourself.

Master cylinder bleeder tool

Here are the necessary master cylinder bleeding kits that you will need.

  • A vacuum pump
  • Brake fluid suitable to your car
  • Towel
  • Line wrench and lug wrench
  • Tape and grease

Gravity bleed master cylinder

This process is all about gravitational force. You can have some rest while gravity does all the hard work. If your master cylinder level is higher than the wheels, this process will work for you.

Ok, let’s start now. Your first task will be filling up the reservoir of the master cylinder with fresh fluid. Look for the wheel that is farthest from the pool. Typically it’s the right rear wheel. Can you see some screws on the brake cylinder? Loosen them.

Now you are free for an hour. Have some rest while reading the other contents of our website to learn something new about cars!

After coming back, tighten the screws. Do the same with the other brake. Now you have another one hour of break time. Feels good when someone else does the work for you, right?

The next step is to top off the fluid of your master cylinder. Repeat the process with the front wheels. Give the brakes about an hour to drain their fluids. Close all the bleeders. The last step will be pumping the brake pedals. It’s all done. Pretty easy, right? Yes, we know.

Pressure bleed master cylinder 

This process involves air pumping into the master cylinder bleeder. Check for any air leaks. You can find the leak by doing a pressure test. If you don’t see any, you are good to add fluids.

Check for any air leaks in the power bleeder and the master cylinder. Set the pressure of the tank to 10psi. Don’t take off the cap of the reservoir while there’s pressure in the tank. Always depressurize before taking the cap off. You can relieve the pressure by taking off the pump cap.

The next step will require you to put about 2 quarts of brake fluid into the pressure bleeder. Set the pressure to 15psi. Never cross the limit of 20psi. Pressure higher than 20psi will damage the hydraulic brakes. You may notice some air pockets forming in the tube. This happens due to the increase in pressure.

Which wheel cylinder usually is far away from the master cylinder? Yes, the right rear wheel. Free the nuts of this wheel first. Then you can go for the left rear, passenger rear, and the rest.

Get a transparent tube, attach it to the bleeder valve. Make sure the fluids are going away from the wheel. You may notice some air bubbles passing through the tube.

Let all the fluid run by opening the bleeder valve. Once the fluid is free of any air bubbles, put the screws back in. Do the same with every wheel. Put some extra pressure into the power bleeder sometimes.

All done? Remove the pump cap and reduce the pressure. Examine the master cylinder’s fluid level carefully. The last thing you might need to check before a test drive is the firmness of the brake pedal.

Brake bleeding vacuum pump

Want to finish bleeding your brakes super fast? Go buy a vacuum pump. Though it’s kind of expensive, it saves time. Also, you don’t need a helping hand.

The vacuum pump almost looks like your kid’s squirt gun. The making process of a vacuum pump is also similar to a squirt gun. It would be good to just use the squirt gun instead of the vacuum pump, right? It would save some money also—tough luck.

You can buy a vacuum pump for around $30. The job is pretty simple. The last two techniques taught you to drain the fluid. Now it’s time to suck some air out of the cylinder.

Put some fluid into your master cylinder. Apply the vacuum to suck out the unwanted air. When all the air is out, simply close the bleeder. Do the same with the remaining wheels.

That’s all the tricks we have in our pockets. With these techniques, you will only need the right tools, not your friends.

How to bleed drum brakes?

Lift your car with a jack. Remove the rear wheel and take them away.
Look for the wheel that is farthest from your car’s master cylinder. Typically it’s the right rear wheel.

Look in the top rear side of the backing plate. Can you see any bleeder screws? Take off the protective cover of the screw. Take a tube and place it carefully on the screw. This tube will let you contain the fluids that are bleeding out. Let the fluid bleed, but not all of it.

Put pressure on the brake pedal. This will cause the fluids to bleed. Once done, let the brake pedal come back to its place. Repeat this procedure with the remaining wheels.

Do you have to bench bleed a master cylinder?

Typically, you don’t need to do a bench bleed. The techniques we have shown are enough to take the air out of your master cylinder. But when you need to bleed your master cylinder quickly, bench bleeding is the answer. You don’t want to spend an hour or half beside the road bleeding your master cylinder. It’s dangerous. So in this situation, you may do the bench bleeding. We will tell you how.

Bench bleeding master cylinder with plugs

This process involves plugging the ports and cycling the pistons of a master cylinder. The first thing you need to do is put brake fluids in the reservoir. Fill it up completely. Then take off the screws to let gravity bleed.

Now it’s time to plug the port. Cycle the piston to get the air out of the master cylinder. Use appropriate bench bleed master cylinder kits. Avoid tools that have sharp ends. Once you have taken all the air out, install your master cylinder.

Bench bleeding a master cylinder with proportioning valve

If your master cylinder has a proportioning valve, you need to remove it before bench bleeding. Place the master cylinder properly. Fill it up with brake fluids. Get a looped brake line from a
bench bleed kit. Insert it into the ports. Put one end of a rubber tube inside the plastic fitting and the other into the cylinder reservoir. 

Put pressure on the plunger with a screwdriver to take the air out. Now fit all the parts in their places.

Bench bleeding master cylinder with vacuum pump

Wipe the cylinder and take off the cap. Replace the old fluid with the new one. Keep the reservoir cap loose. Keep the liquid over the minimum mark. Attach the tube, adapter, and reservoir to the wheel cylinder. Take the wheel off. Do not let the oil go into the bleeding tube.

Open the bleeder screws. Put the bleeder tube and screw together. Pressurize the brake pedal 15 times. This will take any air or fluid off the brake cylinder.


How do you bleed the master cylinder without removing it?

You can bleed the master cylinder by taking the cylinder cover off. Connect a rubber tube to the valve. Drain the fluids by putting pressure on the pedal. Do the same with all the wheels.

How to get the air out of the master cylinder?

The process will require you to bleed the brakes, pressurize the pedal, loose the brake line, drain the fluids. That’s all.

Is it necessary to bench bleed a master cylinder?

Not necessarily. But you need to get the air out of your master cylinder somehow.

Can you bleed the master cylinder while in the car?

Yes, you can. You can bleed your master cylinder by gravity bleeding, pressure bleeding, vacuum pump bleeding.

How to install a master cylinder after bench bleeding?

Follow these steps to
install master cylinder after bench bleeding:

  • Tighten the bolts to recommended torque.
  • Fill the reservoir with fresh fluid.
  • Pressurize the brake pedal.
  • Attach the brake fluid lines and the sensor.

Last words

Hopefully, you have learned how to bleed master cylinder without bench bleeding. If you find this article helpful, tell others about it. If you don’t like anything about this article, we are eager to hear your suggestions.

Remember, no brake can help you if you don’t press it timely. So, never stop looking at the road while driving.

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