Hydraulic Control Assembly - Antilock Brakes: Service and Repair
Anti-lock Brake System Hydraulic Control Unit, Mark 25 E1, from 27 November 2006
Special tools, testers and auxiliary items required
• Torque Wrench (V.A.G 1410)
• Brake Pedal Actuator (V.A.G 1869/2)
Sealing Plug Repair Kit, Part No. 1H0 698 311 A
After separating the control module from the hydraulic unit, the transport protection - 1 - for the valve body must be placed on the hydraulic unit.
Warranties will not be granted for hydraulic units without transport protection.
1 Transport protection for valve domes (foam)
2 M10 sealing plugs
3 M12 sealing plugs
Component location:
The control module is bolted to the hydraulic unit and is located on the right side in the plenum chamber.
CAUTION!
Do not bend the brake lines near the hydraulic unit.
Control Module and Hydraulic Unit, Removing
- On vehicles with a coded radio, note the code. Retrieve it if necessary.
- Disconnect the battery.
- Remove the plenum chamber cover.
- Remove the Engine Control Module (ECM).
- Remove the ground cable from the body behind the ECM bracket.
- Unclip the wiring harness and move it to the side.
- Remove the ECM bracket.
- Remove the intake housing.
- Disengage the connector from the control module in the direction of arrow - 1 - and disconnect (arrow - 2 -).
- Attach the bleeder hose from the bleeder bottle to the left front brake caliper bleeder valve and open the valve.
- Install the (V.A.G 1869/2).
- Close the left front bleeder valve.
- Place sufficient lint free cloths under the control module and hydraulic unit.
Make sure that brake fluid does not come in contact with the terminals.
- Identify the brake lines and remove them from the hydraulic unit and intermediate piece.
- Seal the brake lines and threaded holes with plugs from kit (1H0 698 311 A).
- Pull the hydraulic unit with control module upward from the insulators.
- Remove the hydraulic unit with control module from the bracket.
Control Module, Removing from Hydraulic Unit
- Set the hydraulic unit with control module upward onto a clean, level surface.
- Remove the TORX bolts from the control module.
- Pull the control module off from the hydraulic unit - arrow - without tilting.
- Carefully pull off all sealing rings from the valve domes on the hydraulic unit.
CAUTION!
• On a disconnected control module, the circuit board is open.
• No moisture or dirt particles must get into the control module.
• Avoid a buildup of static electricity!
- Cover the control module magnetic coils with a lint free cloth.
After separating the control module and hydraulic unit, use the transport protection for the valve body.
New Control Module, Installing
CAUTION!
Excessive shaking (for example, dropping, or impact) may destroy the control module. The control module must then no longer be used.
• Surface must be cleaned before assembling.
- Slide all sealing rings - A - on slightly over the valve dome.
- Place the control module without tilting it onto the hydraulic unit.
The sealing rings are then brought into their end position.
- Install the control module to the hydraulic unit with the new TORX bolts diagonally according to specifications.
• A new control module may be installed a maximum of two times to a used hydraulic unit, to ensure that the elastic gasket seals sufficiently.
• Do not install a used control module.
Control Module and Hydraulic Unit, Installing
• Do not remove the sealing plugs from the new hydraulic unit until the corresponding brake line is about to be installed.
• If the sealing plugs are removed too early, brake fluid can leak and the unit may not be sufficiently filled or adequately bled.
- Installation is performed in the reverse order of removal.
- Spray the rubber bushings with silicone lubricant (D 007 000 A2) before installing the hydraulic unit bracket in the plenum chamber.
CAUTION!
When installing the bracket, be careful not to push the rubber insulators. After installing, make sure the hydraulic unit and the control module are secure, otherwise malfunctions will register.
- Remove the (V.A.G 1869/2).
- Bleed the brake system. Refer to => [ Brake System Bleeding ] Service and Repair.
- Enter the radio code.
- Perform the Anti-lock Brake System (ABS) control module (J104) coding using "Guided Fault Finding" in Vehicle diagnosis, testing and information system VAS 5051.
- Perform a basic setting after replacing the ABS control module.
