Notes on repairs to brake system - AH42.00-P-0003-01A

When performing maintenance and repair work on the brake system, it must be ensured that no mineral oil, lubricating grease or similar substances enter the brake system. Only new brake fluid may be used as a flushing and cleaning agent for the cylinders, lines and the expansion reservoir of the hydraulic braking system. If mineral oil is found in the brake system, or if the presence of mineral oil in the brake system is suspected, the procedure below must be followed:

Replace tandem master brake cylinder or brake operating unit and expansion reservoir for brake fluid. Thoroughly flush the entire brake system with new brake fluid. All brake components with parts made of rubber, such as brake calipers, brake hoses, the SBC, ABS, ETS, ASR or ESP hydraulic unit, pressure reservoir, charging piston unit and charging pump, which may have come into contact with mineral oil, must be replaced. Bleed brake system.

Handling of SBC, ABS, ETS, ASR and ESP components in accident vehicles:  If, because of the extent of the damage to the vehicle or the position and external appearance of the hydraulic unit, it is obvious that the hydraulic unit has sustained a severe shock, the hydraulic unit must be replaced. A damaged hydraulic unit can lead to brake power failure. Indications of this are e.g.: Hydraulic lines kinked; Connection on hydraulic unit leaky; Electrical lines or plug couplings damaged; Metal block of hydraulic unit exhibits signs of damage; Hydraulic unit detached from its bracket and cannot be reinstalled without applying excessive force. If this does not apply, the system must be subjected to a rigorous function test and the test steps for the solenoid valves and pump must be performed. A damaged brake system can lead to brake power failure.

Brake calipers must  not be scratched, and the lacquer on lacquered brake calipers must not be damaged, not be removed/installed with hammers, levers, pliers or other tools, not be machined, not be put down on the lacquered side, only be put down on a clean surface. Particular caution must be exercised for the following activities, to avoid damage to the brake calipers:

Detaching/attaching the wheels, removing/installing the brake pads, removing/installing the brake calipers, All work in the area of the wheel wells, e.g. remove/install suspension struts, transverse control arms, stabilizer bars etc, Lowering the vehicle with detached wheels. Lacquered brake calipers are especially sensitive.