Volkswagen Cars 2000-05

Bleeding the ABS System

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Bleeding may be performed using either a pressure bleeder or the manual method. In either case an assistant will be required to depress the brake pedal. Extreme cleanliness must be observed at all times. Do not allow the fluid level to drop below the MIN mark at any time. Do not reuse fluid released during bleeding.


WARNING
If the vehicle is equipped with the Electronic Stability Program (ESP), the ESP pump must be actuated during the bleeding procedure with a proper scan tool, such as VAG 1551, VAG 1552, or equivalent, capable of activating the ESP pump.


NOTE
The brake fluid should be replaced at least every 2 years as it is hygroscopic and absorbs moisture from the ambient air. Always keep brake fluid in a sealed container. Only use a brake fluid that meets the US standard FMVSS 116 DOT 4.


WARNING
Brake fluid is poisonous and corrosive. Avoid spilling brake fluid on the vehicle's paint. It will damage the finish. If a spill does occur, wash it immediately with water.

The purpose of bleeding the brakes is to expel air trapped in the hydraulic system. The system should be checked for fluid condition, brake hose condition and air whenever the pedal feels spongy. The system must be bled whenever it has been opened, repaired, or a hydraulic component replaced. If you are not using a pressure bleeder, you will need an assistant for this job.


WARNING
NEVER reuse brake fluid which has been bled from the brake system. Brake fluid absorbs moisture which can lower its boiling point, therefore re-using old, used, or contaminated fluid can decrease the effectiveness of the braking system.

When bleeding the brakes, air may be trapped in the brake lines or valves far upstream, as much as 10 feet from the bleeder screw. Therefore, it is very important to have a fast flow of a large volume of brake fluid when bleeding the brakes, to make sure all of the air is expelled from the system.


WARNING
Avoid spilling brake fluid on the vehicle's paint. It will damage the finish. If a spill does occur, flush it with water immediately.


NOTE
If the master cylinder reservoir runs dry during the bleeding process, restart from the first fitting.

To bleed the brakes, proceed as follows.

  1. Remove the old brake fluid from the reservoir using a siphon gun or a baster and clean the brake master cylinder reservoir with a clean lint-free cloth. If necessary, remove the reservoir and flush out with brake cleaner.
  2.  


WARNING
When bleeding, the reservoir must be free of all debris and contaminated fluid, otherwise there is a risk that the check valve will become contaminated and fail to function properly.

  1. Bleed the brake system at each fitting. Do NOT proceed to the next fitting until all air bubbles are removed from the previous fitting. Bleed the brakes, making sure to following this sequence:
  2.  

While parts of the of the ABS system can be removed and replaced by the owner of the vehicle, special tools, techniques and procedures are needed to check the operation and performance of the system once repairs are completed.

To check the operation of the ABS system after any of the electronic portions have been replaced or disconnected, the control unit should be interrogated with a suitable scan tool and checked for faults.


NOTE
It is recommended to allow a licensed and trained professional to complete repairs on the ABS system. Most repairs are straightforward, but the diagnosis and testing of the system can enter a different realm. The safety and integrity of the braking system must never be compromised.

To ensure continued proper operation of the braking system, the brake fluid must be changed at least every 2 years. If the vehicle is used for heavy duty use, change the fluid at least once a year. If the vehicle is used in competition or drivers schools, bleed the system before and after each event or at least every 90 days.

Use a quality, approved DOT 4 brake fluid. Use fluid from sealed, unused cans. Buy the fluid in quantities that you expect to use. Buying a large container of fluid and only using a small portion can lead to the remaining fluid to become contaminated over time. Brake fluid is hygroscopic and absorbs moisture, which can lead to system corrosion.


NOTE
Always use a fresh, clean, factory approved brake fluid.


NOTE
Brake caliper bleed screws have a tendency to seize in the caliper body. If seized, spray the bleed screw with a penetrating lubricant. Place a properly fitting deep well, 6-point socket on the bleed screw. Use a T-handle driver to turn the socket, apply equalized rotational pressure to both sides of the T-handle when loosening. This will avoid side loading the bleeder, which due to its relative small size and the fact that it is hollow, the bleeder valve can be easily sheared off. Should this occur, check with your local auto parts vendor for a bleeder valve repair kit. Once the bleeder has been loosened, use a small wrench to open and close the bleeder as necessary while bleeding.


NOTE
The following Pressure bleeding and Non-Pressure bleeding procedures are for models NOT equipped with the Electronic Stability Program (ESP).

Pressure Bleeding

  1. Fill the master cylinder to the maximum level with fresh approved brake fluid.
  2.  
  3. Attach a pressure bleeder, such as US 1116, or equivalent, to the master cylinder reservoir. Do NOT allow the pressure to exceed 29 psi (2 bar).
  4.  


NOTE
An assistant will be needed to properly bleed the brake system.

  1. Raise and safely support the vehicle.
  2.  
  3. If the vehicle is equipped with a manual transmission, attach a clear hose installed into a suitable catch can and open the bleed screw of the clutch slave cylinder until 6 ounces (100 cc) of brake fluid has accumulated into the catch can, then close the bleeder.
  4.  
  5. Remove the protective caps from the bleeder screws and bleed the brakes using the following bleeding sequence. Always starts with the brake unit farthest from the master cylinder. The proper bleeding sequence is:
  6.  


    1.-Right rear
     
    2.-Left rear
     
    3.-Right front
     
    4.-Left front.
     

  7. Insert a tight fitting clear plastic tube over the bleeder screw on the caliper and the other end of the tube in a transparent container partially filled with clean brake fluid.
  8.  


WARNING
When bleeding, Do NOT allow the system to run dry; otherwise, the entire procedure must be repeated.

  1. Open the bleeder.
  2.  
  3. When the fluid being dispersed is free of all air bubbles, close the bleeder valve.
  4.  
  5. Check and top off the brake fluid reservoir and pressure bleeder as necessary.
  6.  
  7. Install the bleeder dust covers.
  8.  
  9. Repeat the brake bleeding steps above for each caliper in the following order.
  10.  
    1. Right rear
    2.  
    3. Left rear
    4.  
    5. Right front
    6.  
    7. Left front
    8.  



NOTE
When bleeding the rear brakes on models equipped with a rear pressure regulator, move the pressure regulator when bleeding the brakes.

  1. Lower the vehicle, check the brake fluid level, top off as necessary and check for normal operation of the brakes.
  2.  

Non-Pressure Bleeding


NOTE
An assistant will be needed to properly bleed the brake system.

Make sure the master cylinder reservoir is clean and filled with fresh, approved brake fluid. During the bleeding procedure check the reservoir often and top off as necessary. If the reservoir is allowed to run dry during the bleeding procedure, the procedure must be started over from the initial procedure.

  1. Raise and safely support the vehicle.
  2.  
  3. If the vehicle is equipped with a manual transmission;
  4.  
    1. Attach a clear hose installed into a suitable catch can.
    2.  
    3. Open the bleed screw of the clutch slave cylinder and have an assistant press and hold the clutch pedal fully pressed.
    4.  
    5. Close the bleed screw.
    6.  
    7. Slowly release the clutch pedal.
    8.  
    9. Repeat the above procedure until the brake fluid is clear and free of all air bubbles making sure to check the fluid level of the reservoir frequently. DO NOT reuse the brake fluid.
    10.  

  5. Remove the protective caps from the bleeder screws and bleed the brakes using the following bleeding sequence. Always starts with the brake unit farthest from the master cylinder. The proper bleeding sequence is:
  6.  


    1.-Right rear
     
    2.-Left rear
     
    3.-Right front
     
    4.-Left front.
     

  7. Insert a tight fitting clear plastic tube over the bleeder screw on the caliper and the other end of the tube in a transparent container partially filled with clean brake fluid.
  8.  


WARNING
When bleeding, Do NOT allow the system to run dry; otherwise, the entire procedure must be repeated.

  1. Press the brake pedal slowly and repeatedly at least 5 times and hold pressure on the pedal.
  2.  
  3. Open the bleeder allowing the brake pedal to travel to and be held on the floor, then close the bleeder valve and slowly release the brake pedal.
  4.  
  5. When the fluid being dispersed is clear and free of all air bubbles, close the bleeder valve, install the bleeder dust cover and move to the next brake caliper. Make sure to check and top off the brake fluid reservoir as necessary.
  6.  
  7. Repeat the brake bleeding steps above for each caliper in the following order.
  8.  
    1. Right rear
    2.  
    3. Left rear
    4.  
    5. Right front
    6.  
    7. Left front
    8.  

  9. Once completed, top off the fluid reservoir as necessary.
  10.  



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Fig.

There is no special bleeding procedure for the ABS system. Refer to the Bleeding procedure located at the beginning of this section.

Front Brakes



  1. Turn the ignition switch OFF.
  2.  
  3. Relieve the brake system pressure.
  4.  
  5. If using pressure bleeder equipment, connect it to the brake fluid reservoir and switch it on.
  6.  
  7. Connect a tight-fitting vinyl hose to the bleeder port of the caliper. If using pressure bleeding equipment, begin at the left front caliper. Immerse the other end of the hose in a container of clean brake fluid.
  8.  


NOTE
Use of a cap or cover on the container is recommended. The brake fluid may bleed with enough force to splash out of an open container.

  1. Open the bleeder screw.
  2.  
  3. Have an assistant depress the brake pedal slowly until the fluid flows without bubbles.
  4.  
  5. Close the bleeder screw before the pedal is released.
  6.  
  7. Remove the vinyl tube from the caliper. Inspect and top off the fluid supply in the reservoir if necessary.
  8.  
  9. Repeat the procedure at the opposite wheel.
  10.  

Rear Brakes



  1. Turn the ignition switch OFF.
  2.  
  3. Relieve the brake system pressure.
  4.  
  5. If using pressure bleeder equipment, connect it to the brake fluid reservoir and switch it on.
  6.  
  7. Connect a tight-fitting vinyl hose to the bleeder port of either caliper. Immerse the other end of the hose in a container of clean brake fluid.
  8.  


CAUTION
Use of a cap or cover on the container is recommended. The brake fluid may bleed with enough force to splash out of an open container.

  1. Open the bleeder screw. Have an assistant turn the ignition switch ON .
  2.  
  3. Press the lever of the proportioning valve towards the axle until brake fluid flows out without bubbles. Release the lever and close the bleeder screw.
  4.  


WARNING
Running time of the ABS pump must not exceed 120 seconds at any one time. If this time is approached or exceeded, a minimum of 10 minutes cooling time is required before proceeding. Do not allow the fluid level to fall below the MIN line at any time.

  1. Switch the ignition OFF while transferring equipment. Remove the vinyl tube from the caliper. Inspect and top off the fluid supply in the reservoir if necessary.
  2.  
  3. Repeat the procedure at the opposite wheel.
  4.  
  5. Once both rear calipers are bled and the service equipment removed, switch the ignition ON until the pump shuts off.
  6.  
  7. Fill the brake fluid reservoir to the MAX line.
  8.  



Click image to see an enlarged view

Fig.



Click image to see an enlarged view

Fig.



Click image to see an enlarged view

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Click image to see an enlarged view

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Click image to see an enlarged view

Fig.

 
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