Carrying out bleeding operation Risk of poisoning Risk of injury - AR42.10-P-0010-02B

Only pour brake fluid into suitable and appropriately marked containers. Wear protective clothing and safety glasses when handling brake fluid .

FRONT AXLE FIXED CALIPER

Number	Designation		Model 129
BA42.10-P-1002-02A	Bleed screw on front axle fixed caliper	Nm	7

REAR AXLE FIXED CALIPER

Number	Designation		Model 129.05/06 0/061/063/064/066/067	Model 129.068/076
BA42.10-P-1002-01A	Bleed screw on rear axle fixed caliper	Nm	7	7

Fig 1: Identifying Socket Wrench (140 589 03 09 00)

Open bleed screw on brake caliper (1) and allow approx. 80 cm³ of brake fluid to flow out without any bubbles , bleeding pressure 2 bar .
Repeat bleeding operation on brake calipers 2, 3 and 4. Allow approx. 80 cm³ of brake fluid to flow out without any bubbles at each brake caliper.
Close bleed screw on brake caliper (1).

Fig 2: Identifying Bleeding Operation On Brake Calipers

Bleeding accumulator of hydraulic unit

This work must only be carried out when the reservoir is empty or work has been carried out on the brake master cylinder, the charging pump, the accumulator, the hydraulic unit and the connecting pipes.
Model 129.076: Connect vehicle wiring harness to brake master cylinder switchover valve (Y61)

Fig 3: Identifying Brake Master Cylinder Switchover Valve
Switch off ignition.
Loosen bleed screw "SP" and empty accumulator.
Tighten bleed screw "SP" and start engine.
Loosen bleed screw "SP" until clear brake fluid escapes without any bubbles (approx. 80 cm ³ ) .
Tighten bleed screw "SP" and wait for the charging process for the accumulator (charge pump runs audibly for approx. 30 s).
Switch off engine.

Fig 4: Identifying Hydraulic Unit & Bleed Screw