Contents: Hydraulic modulator ⬇ Electronic Control Unit (ECU) ⬇ Front wheel sensors ⬇ Rear wheel sensors ⬇
Hydraulic modulator
Attention! On models equipped with ABS, before disconnecting the hydraulic brake lines, be sure to disconnect the battery. Connect the battery only after connecting all hydraulic lines of the brake tract. Violation of this requirement is fraught with air entering the hydraulic modulator, which is removed during the normal bleeding of the system (see section text) is not possible and requires the use of a special electronic tester (VAG 1552).
Before starting work, read the warning text at the beginning of the Section System design, description of individual units and mechanisms.
Removal
Note: Have plugs available to seal open nipple connections. New mounting nuts will also be needed for reassembly.
View the original on the website (SkodaBook.ru)
1. Disconnect the negative battery cable. To minimize hydraulic fluid loss, remove the cap from the master cylinder reservoir, place a polyethylene plug underneath it and screw it back on tightly.
2. Release the lock and disconnect the electrical connector on the hydraulic modulator unit.
3. Carefully wipe the surfaces of the master cylinder and modulator around the brake line connection nipples. Mark the pipes to be disconnected.
4. Loosen the union nuts of the hydraulic line unions connecting the master cylinder to the modulator. Separate the lines from the receiving unions and remove them from the vehicle. Immediately plug the open ends of the unions.
Note: The nuts may be quite tight, so to avoid rounding the splines, loosen them with a special open-end wrench with a slotted head. Be prepared to collect any spilled liquid.
5. Loosen the union nuts and disconnect the remaining four brake pipes from the hydraulic modulator. Plug the open ends of the unions.
6. Loosen the nuts securing the modulator bracket to the brake booster servo unit. Supporting the brake master cylinder, remove the modulator from its place.
Installation
Installation is carried out in reverse order. Pay special attention to the following points:
- a) Remember to replace the mounting nuts and ensure that they are tightened to the required torque;
- b) Fill the brake lines before connecting them (and fittings on the modulator) with fresh hydraulic fluid (see section Bleeding the hydraulic system). Make sure that the tubes are connected correctly and that the union nuts are tightened securely;
- c) Make sure that the electrical connector is securely fixed with the clamp;
- d) Bleed the hydraulic system (see section Bleeding the hydraulic system) and connect the negative cable to the battery;
- e) As soon as possible, take the vehicle to a service station to check the proper functioning of the ABS using special diagnostic equipment.
Electronic Control Unit (ECU)
Removal
Note: Have plugs available to seal open fittings after removing the ECU separator from the hydraulic modulator.
1. Remove the hydraulic modulator assembly from the ECU.
2. Unscrew the bolts securing the ECU to the base of the hydraulic modulator. Release the clamps and separate the ECU from the modulator. Immediately seal the open ends of the fittings on the modulator with the plugs prepared in advance.
Caution! Do not tilt or turn over the ECU removed from the modulator to avoid damaging the valve pins.
Installation
Installation is carried out in reverse order.
Note: Be extremely careful when connecting the ECU to the modulator. Tighten the mounting bolts diagonally to the required torque and install the hydraulic modulator in its original place on the vehicle.
Front wheel sensors
Removal
1. Disconnect the negative cable from the battery.
2. Set the parking brake, then jack up the front of the vehicle and support it. Remove the appropriate front wheel.
3. Walk from the sensor along the electrical wiring, releasing it from the intermediate clamps and remembering the route of the wiring. Disconnect the electrical connector.
4. Loosen the mounting bolt and remove the sensor from the hub assembly.
Installation
1. Thoroughly clean the mating surfaces of the sensor and hub assembly, then lightly lubricate the walls of the sensor seat in the hub with a universal grease such as Gleitmo 165 or Wolfracote.
2. Check the condition of the sensor working element, then place the latter in its regular place in the hub assembly. Screw in the mounting bolt and tighten it with the required force.
3. Move along the electrical wiring, fix it in all the intermediate fasteners provided. Connect the electrical connector. Replace the wheel, lower the car to the ground and tighten the wheel bolts to the required force.
Rear wheel sensors
Removal
1. Support the front wheels with chocks, then jack up the rear of the car and place it on stands. Remove the corresponding rear wheel.
2. Walk from the sensor along the electrical wiring, releasing it from the intermediate clamps and remembering the route of the wiring. Disconnect the electrical connector.
3. Unscrew the mounting bolt and remove the sensor from the axle hub.
Installation
1. Thoroughly clean the mating surfaces of the sensor and hub assembly, then lightly lubricate the walls of the seat for the sensor in the hub with a universal grease such as Gleitmo 165 or Wolfracote.
2. Check the condition of the sensor working element, then place the latter in its regular place in the hub assembly. Screw in the mounting bolt and tighten it with the required force.
3. Move along the electrical wiring, fix it in all the intermediate fasteners provided. Connect the electrical connector. Replace the wheel, lower the car to the ground and tighten the wheel bolts to the required force.