Bleeding the brake system (VW Transporter T3)

After each brake repair, during which the system fails, air may get into the pressure pipes. In this case, it must be removed. A sign of the presence of air in the pipes is the characteristic reaction of the brake pedal when it is pressed. In this case, it is necessary to eliminate the leak and bleed the brake system.

The brake system is freed from air by bleeding it using the brake pedal; for this you need an assistant.

When handling brake fluid, keep the following in mind:

• brake fluid is highly toxic.
• brake fluid has a corrosive effect, so it should not come into contact with car paint.
• brake fluid is hygroscopic, i.e. it absorbs moisture from the air. Therefore, it must be kept in closed containers.
• brake fluid can be used in the brake system only once. When bleeding the system, only new brake fluid is used in accordance with US standards FMW 116 DOT 4.
• the brake fluid in the system should be replaced every two years.

Removal air

If you need to remove air from the entire system, you need to do this with each wheel brake cylinder and, accordingly, with each brake pad. This happens if air has entered each brake cylinder. If only one cylinder has been replaced or overhauled, it is enough to remove air from it only.

Bleeding sequence: 1. rear right brake cylinder, 2. rear left, 3. front right brake pad, 4. front left.

Place the car on a level surface.

Remove the cap from the expansion tank and add brake fluid to the maximum mark.

Remove the cap from the air valve of the brake cylinder and use the socket wrench.



Attach a clean hose; and insert the other end into a bottle half filled with brake fluid.

The assistant should press the brake pedal so often ("pump") until pressure is created in the brake system. This is felt by the increased resistance of the pedal.

If the pressure is sufficient, press the pedal all the way down and hold it in that position.

Open the brake cylinder air valve half a turn with a wrench. Collect the leaking brake fluid in a bottle. Make sure that the end of the hose in the bottle is always below the fluid level.

Repeat the process of pumping each cylinder until there are no air bubbles in the liquid flowing into the bottle.

With the pedal depressed, tighten the air bleed plug.

Remove the hose from the air valve and put on the protective cap.

Bleed the other brake cylinders in the same manner.

Caution! When bleeding, observe the equalizing reservoir from time to time. The fluid level must not fall too low, otherwise air will be sucked in through the reservoir. Always top up with new brake fluid!

Fill the reserve reservoir with new brake fluid.

Caution! The liquid level must be below the maximum mark even with the cap screwed on.

Check the ventilation hole in the lid for free passage.