Replacing brake fluid (Audi A4 B6)

As mentioned above, brake fluid should be changed once every two years, if possible at the end of the cold season. In workshops, a special filling device is used for this. However, you can do this work yourself - it is similar to the work of removing air. About 1.5 liters of fresh brake fluid is needed for replacement (please note the specification).

1. Follow all instructions and procedures described in the section "Bleeding the brake system".

2. In vehicles with a manual transmission, the hydraulic system for controlling the clutch must also be flushed with new brake fluid. To do this, read the instructions in the chapter "Power transmission" on bleeding air from the hydraulic drive of the clutch control. To completely replace the fluid, at least 0.1 l of brake fluid must be pumped out of the working cylinder of the clutch control drive.

3. The working operations performed on individual air valves are no different from the operations performed when removing air. Naturally, it is necessary to constantly pour brake fluid into the expansion tank. To completely replace the brake fluid, at least a quarter of a liter of liquid must be pumped out through each of the air valves. The pumped out liquid must be transparent and without bubbles.

To prevent brake fluid from leaking out

When separating the brake pipe (or a hose) brake fluid is leaking from the reservoir. This can be prevented. Before unscrewing the threaded connection, loosen the air valve to remove air from the corresponding brake circuit. Attach a hose to it to remove air, and lower the opposite end of the hose into a clean container. Then fully depress the brake pedal and fix it in this position, for example, with a wooden strip. The openings of the supply channel in the master brake cylinder are closed, so the brake fluid will not leak.

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