Attention! Remove air from the system only when the engine is idling.
For auto «4,6is» with engine «M62» And «4,8is» with engine «N62» new brake fluid required «DOT4» with reduced viscosity. Bleeding the brake system «DSC 5.7» necessary after every repair of the brake system if the hydraulic brake or clutch system has been opened and air has entered it. A sign of the presence of air in the system is «failure» brake pedal when pressed. To remove air from the brake system by pumping it on the diagnostic stand «DIS-BMW» or using the brake pedal, with the obligatory participation of an assistant.
Bleeding the brake system using the system «DIS-BMW» must be done in the following order.
Strictly follow the instructions for filling and bleeding the brake system when replacing or repairing its elements:
- master brake cylinder;
- hydraulic unit;
- connection elements of the brake system;
- lift pump.
After work on the booster pump, it is only necessary to bleed the front wheel brake drive circuit. Before flushing the brake system, it is necessary to turn on the booster pump once using the system «DIS-BMW», while a bleeder with a maximum pressure of 2 bar must be connected.
Remove the heater baffle and connect the diagnostic system «DIS-BMW» (pic. 11.63) and set the mode for pumping the hydraulic unit of the DSC system. Install the bleeder tool on the brake master cylinder expansion tank. Enable diagnostic system «DIS-BMW», strictly comply with the operating instructions for the system, the pressure must not exceed 2 bar.
Flushing the brake system assembly is carried out in the following order:
- connect one end of the hose to the receiving vessel (pic. 11.64);
- connect the other end to the head of the fitting of the rear right wheel caliper;
- unscrew the fitting and pump the hydraulic drive until clean brake fluid without air bubbles flows:
- turn the fitting;
- repeat the operation on the rear left wheel.
Bleed the brake circuit of the rear wheels in the following order:
- connect one end of the hose to the receiving vessel (pic. 11.64);
- connect the other end to the head of the fitting of the rear right wheel caliper;
- open the fitting;
- execute the pumping program using the system «DIS-BMW» with the bleed valve open;
- after completing the program, press the brake pedal five times to the stop;
- clean brake fluid must flow out, without air bubbles;
- turn the fitting;
- repeat this operation on the rear left wheel.
Bleed the brake circuit of the front wheels in the following order:
- connect one end of the hose to the receiving vessel (pic. 11.65);
- connect the other end to the front right wheel caliper fitting head,
- open the fitting;
- execute the pumping program using the system «DIS-BMW» with the bleed valve open;
- after completing the program, press the brake pedal five times to the stop;
- clean brake fluid must flow out, without air bubbles;
- turn the fitting;
- repeat this operation on the front left wheel.
Switch off the brake fluid changer and disconnect it from the reservoir.
Check brake fluid level (arrow, fig. 11.66). Make sure you have a rubber gasket (1) lids and close the tank.
In the absence of diagnostic equipment, bleeding of the brake system can be carried out together with an assistant.
Attention! Constantly monitor the level of brake fluid in the compensation tank and maintain it at the mark «max».
Always add only fresh brake fluid.
It is recommended to start pumping from the caliper that has been replaced or repaired.
Strictly observe the sequence of pumped brake mechanisms, this will help save time and effort:
- rear right brake caliper:
- rear left brake caliper,
- front right brake caliper;
- front left brake caliper.
Bleeding the brake system must be carried out in the following order.
Remove the dust cap, clean the bleeder valve on the caliper and assemble the circuit to bleed air from the hydraulic brake drive system by putting a clean hose on the nipple and lowering its other end into a container (bank), half filled with brake fluid. The use of a transparent container and hose is recommended.
Repeatedly (5–7) depress the brake pedal until there is a sharp resistance. Leave the pedal depressed.
Open the bleed valve half a turn with the ring wrench (bleed valve). Collect leaking brake fluid in a container. Make sure that the end of the hose is constantly immersed in the liquid.
If the pressure drops, close the bleeder valve.
again several times (5–7) press the brake pedal until there is a sharp counteraction. Leave the pedal depressed.
Continue the above process until, together with the brake fluid, no air bubbles stop flowing into the fluid collection container.
Close the bleed valve, release the brake pedal, remove the brake fluid outlet hose and install it on the bleed valve (bleed valve) protective cap.
Remove air from all brake mechanisms in the same way.
Check the safety of the braking system.