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How to Bleed ABS Module without Scan Tool

Nowadays, vehicles are equipped with many systems to protect the driver. Anti-lock Braking System (ABS) is also one of them. As time gone by or in any case, your break pedal will feel soft. The reason for this is that we push out the air way first before we reach for the fluid to do its job. Therefore, you can be in danger because it means that the car will take longer to stop. There are some ways to bleed the ABS module that requires specific tools, such as a scan tool. But what if you cannot afford one? This post will let you know how to bleed abs module without scan tool.

What is an Anti-lock Braking System (ABS)?

Before knowing how to bleed ABS brakes, let’s find out what is an ABS and why do we need one?

ABS or an Anti-Lock Braking System is a piece of safety equipment that prevents the wheels of a vehicle from locking up under emergency, panic, or harsh braking conditions and helps them maintain grip with the road.

how to bleed abs brakes
Anti-Lock Braking System is a piece of safety equipment that prevents the wheels of a vehicle from locking up under emergency (Source: Head Topics)

There are four major components of a typical anti-lock braking system:

  •       Speed sensors – They keep track of how fast the wheel or wheels are rotating
  •       Valves – Valves in the brake line allow, block and release pressure on the brakes by assuming three different positions
  •       Pump – These pumps are filled with hydraulic fluid and apply pressure to the brake drums or calipers on demand
  •       Controller – The electronic control unit (ECU) is the brain of the ABS and uses data from the sensors to determine whether to pump the brakes or not.

What Happens When Air Gets into the ABS System?

Air gets inside the braking system every time you open it for some repairs or other purposes. And some air inside the system affects the brake pedal’s impact, making it feel soft like a sponge upon pressed. When you brake, the hydraulic fluid transfers this pressure to other brake components. However, when there is air in the system, pressing on the pedal compresses the air first, making the pedal feels squashy.

bleeding brakes with abs
Some air inside the system affects the brake pedal’s impact, making it feel soft like a sponge upon pressed (Source: Ελαστικά αυτοκίνητου superservice)

Sometimes, the pedal feels strangely low and sluggish in response when you are pressing it to slow down the car in traffic. It is a warning sign indicating air bubbles in the brakes. You must remove these unwanted bubbles by bleeding brakes with ABS.

How To Bleed ABS Module Without Scan Tool?

Bleeding ABS brakes is more challenging than the process of bleeding the brake system because the ABS module has a lot of chambers and moving parts in it. Most ABS modules do have bleeding valves but usually these are not enough to take all the air out. While it is a time-consuming work but for a DIY-er, the process is not too complicated. Here are the steps of how to bleed air from ABS module. Follow the instruction below and you will know how to bleed ABS brakes without scan tool.

Things You Will Need

Bleeding the ABS module is not so difficult to do. But it might take some time because you need to bleed each wheel separately. If wonder how to bleed ABS module without scan tool, here are the tools you need:

  •       Car Jack
  •       Turkey baster
  •       Drip pan
  •       Brake fluid
  •       Tubing
  •       Hammer
  •       Lug wrench
  •       Car Stands

Step 1 – Getting Ready

First, you will need to park the car on a flat level with good lighting and ventilation condition. Engage the parking gear to make sure that the emergency brakes are applied.

Step 2 – Removing The Wheels

Using the car jack, lift the car to a comfortable level that you can remove the four wheels comfortably so that you can reach the bleeders easily.

Step 3 – Drain the Brake fluid

The brake fluid resolve is placed under the hood of your car. It is a small transparent container with metal tubes connecting to each wheel. These are the so-called brake lines. When you have located the reservoir, empty the old brake fluid completely and refill it with new one. Make sure that you get the right fluid for your car by asking your trusted mechanic before buying.

bleed abs brakes without scan tool
The brake fluid resolve is placed under the hood of your car (Source: Auto repair shop in Destin Fl)

Step 4 – Locate the Brake Bleeder Screw​

The next step of how to bleed abs module without scan tool is reaching the bleeding port in the brake caliper. Use the correct bleeder wrench to loosen the bleeder screw, remove the dust cap and take the vacuum hose, tubing and put one end of it in an empty plastic bottle and the other end attached to the bleeder screw.

how to bleed abs module without scan tool
Pump the brake continuously until all the fluid has been drained into the bottle (Source: CarNewsCafe)

Take someone with you as a helping hand to pump the brake continuously until all the fluid has been drained into the bottle. Once done with all the wheels, you can confirm if the brake fluid reservoir is indeed empty. ​

Step 5 – Tighten The Bleeder Screw And Refill The Cylinder

Just before returning the bleeder screw, ask your friend to press the break pedal down and hold it there. Open the bleeder screw to let trapped air get out and tell him to keep holding the pedal until you are sure that the bleeder screw is tight as it was before. You have to repeat this process several times to ensure no air bubbles are left in the brake lines.​

Keep in mind that you have to do this for all the wheels, and it must be in the following order: Right rear, left rear, right front, left front.

The bleeding process varies depending on the model of the vehicle or the ABS system that you have. The steps we mentioned should work for most generic ABS.

After that, open the master cylinder and refill with new brake fluid until it reaches the full level.​ Make sure that when you are draining the brake fluid, keep checking the fluid levels on the master cylinder so as not to drain the cylinder and letting air get into the system.

Step 6 – Check For The Leaks

After bleeding all the brake lines, tell your friend to pump the pedal and you walk around the vehicle to check if there are any leaks because of pumping. During this, your friend should ensure the pedal goes up and down to the recommended levels. ​

Step 7 – Put the Parts back Together

The last step of how to bleed ABS module without scan tool is to refit all the wheels back and be ready to test your brakes. Take a test drive to see if the brakes are working right. Also remember to clean the area as you might have let the residue liquid pour around. Safety first!

SEE MORE:

When You Should Bleed The Brake System

In normal operation, you do not need to bleed the brake system. But there are some cases that will require bleeding it:

  • The brake pads are completely worn out: This causes the fluid level in the master cylinder to drop. If it drops too far, air gets into the brake system. By then you will have to read again how to bleed ABS module without scan tool in case you do not have one.

    bleed abs brakes without scan tool
    The brake pads are completely worn out (Source: Ultra Tune Urangan)
  • Disc brake caliper or drum brake cylinder replacement: This requires disconnecting the brake lines. When that happens, air will enter the brake lines.
  • Replacement of some other brake system components: A disconnected hydraulic part within the brake system causes air to get into the brake lines. The master cylinder is a good example.
  • Compressed caliper piston: Sometimes you need to open the bleeder valve to compress the piston while changing brake pads. This can allow air to enter the brake lines.

Conclusion

How to bleed ABS module without scan tool may seem a little bit difficult but regardless of the type of car you have, the steps we showed should help you get over with the problem. You need to prepare well before hand because the task is repetitive and requires you to be accurate when emptying the brake fluid. Also, you will need a friend to be the a partner during this long and, maybe, boring process.

Hopefully this post will help you if you have decided to bleed the ABS module at home and without a scan tool. If you know any better solutions or suggestions, feel free to comment below and keep track with us for more useful tips.

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