Hydraulic System, Bleeding

WARNING: This page is about a different car, the 2023 Audi S3, 2023 Audi RS 3, 2023 Audi A3 Quattro, and 2023 Audi A3. However, it is still accessible from the selected car via links, so may be relevant.

Special tools and workshop equipment required

Bleeding Equipment:VAS 6860 or Brake Charger/Bleeder Unit:VAS 5234

Fig 1: Brake Filling and Bleeding Equipment : VAS6860
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Brake Charger/Bleeder Unit - Adapter:VAS 5234/1A
Collection bottle from the Bleeding Equipment:VAS 6860 or Brake Charger/Bleeder Unit:VAS 5234

Fig 2: Brake Charger/Bleeder Unit VAS5234
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Wrench - Brake Bleeder Set:VAS 5519

Fig 3: Identifying Brake Bleeder Socket VAS 5519
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Brake Bleeding Tool Set:VAS 6564

Fig 4: Identifying Tool Set : VAS6564 For Brake Bleeding
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Bleed brakes

The brake system is divided diagonally:

Left front wheel and right rear wheel.
Right front wheel and left rear wheel.

Depending on the wheel combination, remove the wheels. Refer to WHEELS AND TIRES .

Component	Conventional bleeding	Bleeding
Brake line from brake booster to hydraulic unit	1	2
Hydraulic Unit	1	2
Suction Line	1	2
Brake line from hydraulic unit to brake caliper	1	-
Brake Caliper	1	-

1. Conventional bleeding

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-- Attach the Brake Bleeder Adapter:VAS 5234/1A to the brake fluid reservoir (example illustration).

-- Connect the filling hose from the Brake Filling and Bleeding Equipment:VAS 6860 or Brake Charger/Bleeder Unit:VAS 5234 .

-- Set a work pressure of 2.0 bar (29.01 psi) at the Bleeding Equipment:VAS 6860 or Brake Charger/Bleeder Unit:VAS 5234 and turn it on. Refer to Service Information.

-- Remove the protective cap -3- from the bleed screw -1- on the respective brake caliper (example illustration).

Fig 5: Identifying Protective Cap, Bleed Screw And Container Bleeder Hose

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Use a suitable bleeder hose -2-. It must be seated tightly on the bleed screw so that no air can enter the brake system.

The six-piston brake calipers each have two bleed screws.

Fig 6: Bleeding Rear Brakes

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-- Position the socket -3- at the bleed screw using the ratchet -2-.

-- Attach the bleeder hose -1- through the socket onto the bleed screw.

-- Position the socket -3- at the inner bleed screw using the ratchet -2-.

Fig 7: Bleeding Rear Brakes

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-- Attach the bleeder hose -1- through the socket onto the bleed screw.

Bleed the brake caliper at each bleed screw.

Bleeding sequence

Outer Left Front Six-Piston Brake Caliper
Left front inner brake caliper
Outer Right Front Six-Piston Brake Caliper
Right front inner brake caliper
Left Rear Brake Caliper
Right Rear Brake Caliper

-- Open the bleed screw and leave open until the leaking brake fluid is clear and without bubbles.

-- Press brake pedal five times to assist the bleeding procedure.

-- Tighten the bleed screw, remove the bleeder hose and place the protective cap on the bleed screw.

-- Repeat the bleeding procedure in the specified sequence for the remaining brake calipers.

-- Fill the brake fluid reservoir under consideration of brake pad wear up to the "MAX" mark and tighten the fuel cap (example illustration).

Fig 8: Brake Fluid Reservoir

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-- Carefully remove leaked brake fluid.

-- Start the engine and check the brake pedal travel and pressure.

If the brake pedal travel and brake pedal pressure are not OK, perform the bleeding procedure using the Vehicle Diagnostic Tester.

2. Bleeding using the Vehicle Diagnostic Tester

-- Connect the battery charger. Refer to BATTERY, CHARGING .

-- Attach the Brake Bleeder Adapter:VAS 5234/1A to the brake fluid reservoir (example illustration).

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-- Connect the filling hose from the Brake Filling and Bleeding Equipment:VAS 6860 or Brake Charger/Bleeder Unit:VAS 5234 .

-- Set a work pressure of 2.0 bar (29.01 psi) at the Bleeding Equipment:VAS 6860 or Brake Charger/Bleeder Unit:VAS 5234 and turn it on. Refer to Service Information.

-- Select the "0003 - Basic Setting, Brake Bleeding" program. Refer to DIAGNOSTIC ENTRIES .

-- Follow the instructions in the Vehicle Diagnostic Tester display.

-- Check the brake pedal travel and brake pedal pressure after bleeding.

If the brake pedal travel and brake pedal pressure are not OK, repeat the bleeding procedure using the Vehicle Diagnostic Tester.

-- Remove the Adapter:VAS 5234/1 from the brake fluid reservoir.

-- Fill the brake fluid reservoir under consideration of brake pad wear up to the "MAX" mark and tighten the fuel cap (example illustration).

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CAUTION:

There is a risk of contamination and paint damage from leaking brake fluid.

- Rinse off any leaking brake fluid immediately using plenty of water.

A road test must be performed after bleeding. During this, at least one ABS control must be performed!

CAUTION:

Faulty brakes increase the risk of an accident.

- Make sure the brakes are working correctly before driving the vehicle for the first time.

Tightening Specifications