TT L4-1.8L Turbo (BEA) (2004)
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Brake Bleeding: Service and Repair
ABS/ESP ITT Mark 20
ABS/ESP ITT Mark 20, bleeding brake system
WARNING:
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Do not under any circumstances allow brake fluid to come into contact with liquids which contain mineral oils (e.g. oil, grease, cleaning
agents). Mineral oils damage the plugs and seals in the brake system.
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Brake fluid is poisonous and must not under any circumstances be siphoned through a tube using the mouth. Because of its caustic
properties it must not come into contact with paintwork.
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Brake fluid is hydroscopic, i.e. it absorbs moisture from the surrounding air, and should always be stored in airtight containers.
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Always observe the relevant environmental regulations for disposal.
System must first be pre-bled when one chamber in the brake fluid reservoir is completely empty (e g brake system leaking).
Afterward the hydraulic unit must be bled with vehicle diagnostic, testing and information system VAS 5051 in function "04. Basic setting".
When using a brake filler and bleeder unit (such as VAS 5234) to replenish the brake fluid, make sure that filling pressure does not exceed 1 bar.
If the filling pressure exceeds 1 bar, a hydraulically controlled change-over valve (which is required for the EDL function) prevents unrestricted
flushing of the EDL related parts of the hydraulic unit. If this is the case, it may not be possible to bleed the system properly.
For this reason the brake fluid pressure must be reduced to 1 bar on the brake filling and bleeding appliance
,Refer to Operating instructions for VAS 5234
Note:
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Use only new brake fluid with part No. B COO 700 A. (Container contents available from O. 25 to 30 litres).
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Rinse off any brake fluid spillages using plenty of water.
Brake filler and bleeder unit VAS 5234, bleeding brake system
Special tools and equipment
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Brake filler and bleeder unit VAS 5234
Work sequence
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Connect brake filler and bleeder unit VAS 5234.
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Remove protective cap from bleeder screw on brake caliper and attach bleeder bottle hose to bleeder screw.
Bleeding sequence
1. Left front brake caliper
2. Right front brake caliper
3. Left rear brake caliper
4. Right rear brake caliper
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Leave bleeder screw open, with bleeder bottle hose connected, until brake fluid emerges out of the bleeder screw clear and free from air bubbles.
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Build up pressure in brake system to aid bleeding by pumping pedal five times.
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Tighten bleeder screw to 10 Nm. Detach hose and install protective cap on bleeder screw.
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Repeat procedure on remaining brake calipers in the specified bleeding sequence.
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Top off fluid level in reservoir to "MAX" mark (according to degree of pad wear) and close reservoir cap.
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Start engine and test pedal travel and pedal pressure.
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If the pedal travel is excessive, check brake system for leaks or repeat bleeding procedure.
