The hydraulic unit structurally consists of an electronic control unit (ECU) and a hydraulic modulator containing electromagnetic valves (EMC), a return pump and a return pump electric motor (EVN)
Removing the ABS hydraulic unit
Preparing the car for the task
Disconnect the negative battery terminal
Disconnect the wiring harness block from the hydraulic unit
Disconnect the brake pipes going to the brake mechanisms, the pipes of the primary and secondary circuits of the master brake cylinder from the ABS hydraulic module.
We install plugs in the holes of the pipes and the hydraulic unit
Loosen the tightening of two nuts 8 securing the hydraulic unit to the bracket and remove the hydraulic unit
Installation
In the spare parts store, the hydraulic unit is delivered filled. Before installation, you need to make sure that the hydraulic unit support damper is present and correctly installed
We install the ABS module on the bracket, aligning the grooves on the rubber bushings with the slots on the bracket, and tighten the nuts 8 to a torque of 8 ± 2 Nm.
We take out the plugs and connect the tubes of the primary and secondary circuits, the tubes leading to the brake mechanisms to the hydraulic unit.
Check the level of brake fluid in the reservoir of the hydraulic brake drive, if necessary, add it to the norm.
The brake fluid level in the brake master cylinder reservoir must reach the lower edge of the filler neck with the cap installed.
Removing air from the brake system in case of installation of an empty hydraulic unit
When installing an empty hydraulic unit on a vehicle, bleed the brake system using the DST-2, 10.12 diagnostic tool with the appropriate firmware in the following sequence.
Connect the socket of the diagnostic device DST-2, 10.12 with the appropriate firmware to the vehicle diagnostic block.
Turn on the ignition and wait for the connection with the vehicle's electrical equipment to be established.
Press the "1" button of the tester, enter the "Chassis" menu and select the ABS 9.0 diagnostic program in it, press the "Enter" button.
When using a device for bleeding the brakes, work in accordance with the operating instructions for the device.
If there is no device for bleeding the brakes, the bleeding operation must be performed by three performers (operators).
Operator No. 1 is constantly in the driver's seat, controls the operation of the diagnostic tester, presses the brake pedal and issues commands to Operator No. 2.
Operator No. 2 follows the instructions of Operator No. 1 (opens and closes the bleed valves).
Operator No. 3 constantly tops up the brake fluid in the reservoir of the hydraulic brake drive, preventing its bottom from being exposed, in order to prevent air from entering the hydraulic drive.
Press the "4" button of the device and enter the "ABS bleeding" menu.
By pressing the "Enter" button and then the "2" button, switch to the mode of manual bleeding of the brake system (the device program automatically switches to the "Phase No. 1" mode - the rear left wheel of the car).
Put a transparent hose on the fitting, immerse the other end of the hose in a vessel partially filled with brake fluid.
Operator #1 commands operator #2 to open the brake bleed valve.
Operator #1 presses the tester's "Enter" button and performs a series of actions consisting of pressing, holding for 1 to 2 seconds, and fully releasing the brake pedal throughout the bleeding phase.
At the end of the "Phase No. 1" mode of pumping, operator No. 2 team wraps the fitting.
Operator No. 1 sharply presses the brake pedal and, holding the pedal depressed, gives a command to Operator No. 2 to unscrew the fitting.
After unscrewing the fitting 1/2 - 3/4 of a turn, after 1 - 2 seconds, while holding the brake pedal down, the fitting is screwed in and operator No. 1 releases the pedal.
Repeat the bleeding operation until no more air bubbles come out of the car's brake system.
If the ABS diagnostic lamps in the control lamp unit do not light up, and the diagnostic tool does not switch to the "Phase No. 1" mode, it is necessary to clear the memory of the ABS controller from accumulated errors using the diagnostic tool.
While depressing the brake pedal, tighten the bleed screw, release the pedal and remove the transparent hose. Wipe the nozzle dry and put on a protective cap.
WARNING. Full release of the brake pedal is necessary to signal the bleeding process to the ABS controller.
The bleeding process is indicated on the display of the diagnostic tester in the form of an increasing dark bar at the bottom of the screen, the ABS diagnostic lamps in the control lamp unit are lit at this moment.
If, after the end of the bleeding phase, the message "Filling failed" appears on the display of the tester, it is necessary, by pressing the "Esc" and "Enter" buttons, to make a second attempt to bleed the corresponding circuit of the brake system, but not earlier than after 5 minutes.
During the bleeding process, do not empty the reservoir of the hydraulic brake drive.
It is not allowed to use the liquid drained through the fitting to top up the hydraulic brake reservoir during the day.
Press the up button on the scan tool and place it in Phase #2 Front Left Wheel Bleed Mode. The sequence of operations is the same as for the rear left wheel.
Press the up button on the scan tool and place it in Phase #3 Front Right Wheel Bleed Mode. The sequence of operations is the same.
Press the up button on the scan tool and place it in the "Phase #4" rear right wheel bleed mode. The sequence of operations is the same.
Depress the brake pedal and check that there is no "soft brake" effect. By pressing the "Esc" button of the diagnostic tool, enter the initial mode of operation.
By pressing the tester buttons "1", "Enter", "4" in succession, go to the "Fill Status" mode (the message "Completed" should be on the right side of the display).
Press the "Esc" button once, turn off the ignition and disconnect the diagnostic tool connector from the car's diagnostic connector.
Check and, if necessary, top up the brake fluid level in the brake fluid reservoir.
Create the maximum possible load on the brake pedal with your foot and check the tightness of the hydraulic drive. The brake pedal must not fall when pressed.
Test the effectiveness of the service brake on a test drive or on a stand