Hydraulic Control Assembly - Antilock Brakes: Service and Repair
WM 453019 Removing and installing hydraulic unit
Preliminary work
Preliminary work for removing and installing hydraulic unit
1. Remove side engine compartment cover. -> 700219 Removing and installing front cover (engine compartment) - section on "Removing"
2. Remove air-cleaner box. -> 242519 Removing and installing air cleaner housing - section on "Removing" Service and Repair
Removing hydraulic unit
Information
- When fitting the hydraulic connections, the electric plug connections on the control units must remain connected as long as possible. This prevents the plug connections on the hydraulic unit or in the connectors inside from being splashed with brake fluid or water.
- Any damp connector must be wiped dry before being disconnected from the connector on the hydraulic unit. If necessary, provide the connector with a suitable protector.
- Brake fluid on electrical contacts (even thinned brake fluid) leads to corrosion and may cause faults in the system.
- The brake lines must not be bent in the area of the hydraulic unit.
- Clean the interfacing points of the brake lines, but not with cleaning agents.
- Rinse off any brake fluid emerging thoroughly with water.
Information
- The pictures shown in this document may differ from the original.
- However, this does not affect the validity and relevance of the pictures.
Installation position of hydraulic unit
1. Close the central valves of the tandem brake master cylinder.
This prevents too much brake fluid from running out of the open brake system.
Proceed as follows:
1.1. Actuate the brake pedal by hand using the brake pedal actuator (do not tighten it yet).
1.2. Attach the vent hose of the vent bottle to the bleeder screw of the brake caliper at the front left and rear left (2nd mechanic required).
1.3. Open the bleeder screws until the brake pedal is pressed down fully.
1.4. Tighten the brake pedal actuator and close the bleeder screws.
2. Mark the hydraulic lines => Position of hydraulic lines.
Position of hydraulic lines
3. Release electric plug connection -1- from the hydraulic unit -2- ( -a- ) and pull it off -A-.
Electric plug connection for hydraulic unit
4. To protect the body from emerging hydraulic fluid, cover the area under the hydraulic unit with cloths.
If hydraulic fluid runs onto the body, immediately rinse the area thoroughly with water.
5. Remove hydraulic lines. => Position of hydraulic lines
Close off the loosened lines with suitable stoppers.
6. Remove the hydraulic unit -1-.
To do this, lever the hydraulic unit out of the body using a suitable tool -2-.
Removing hydraulic unit
7. Remove the hydraulic unit.
Installing hydraulic unit
Information
- When fitting the hydraulic connections, the electric plug connections on the control units must remain connected as long as possible. This prevents the plug connections on the hydraulic unit or in the connectors inside from being splashed with brake fluid or water.
- Any damp connector must be wiped dry before being disconnected from the connector on the hydraulic unit. If necessary, provide the connector with a suitable protector.
- Brake fluid on electrical contacts (even thinned brake fluid) leads to corrosion and may cause faults in the system.
- The brake lines must not be bent in the area of the hydraulic unit.
- Clean the interfacing points of the brake lines, but not with cleaning agents.
- Rinse off any brake fluid emerging thoroughly with water.
1. Insert the rubber buffers -1- into the mounting points in the body.
When inserting the rubber buffers, check that they are not damaged and are fitted correctly. This is the only way to ensure optimal noise insulation.
Installing hydraulic unit
2. Fit the fastening pins -2- of the hydraulic unit -3- into the rubber buffers -1- ( -A- ).
Spray the rubber buffers -1- with soap suds to facilitate installation.
3. Fit the hydraulic lines according to the marking on the hydraulic unit => Position of hydraulic lines. -> 4X00IN Tightening torques for brake hydraulics [1][2]Hydraulic System, Brakes
Do not remove the stoppers on the new hydraulic unit until the relevant line is fitted.
Position of hydraulic lines
4. Plug in electric plug connection -1- for the hydraulic unit -2- ( -A- ) and lock it -a-.
Fitting electric plug connection
Subsequent work
Subsequent work for removing and installing hydraulic unit
1. Install air-cleaner box. -> 242519 Removing and installing air cleaner housing - section on "Installing" Service and Repair
2. Install side engine compartment cover. -> 700219 Removing and installing front cover (engine compartment) - section on "Installing"
3. Bleed the brake system. -> 470107 Bleeding the brake system Service and Repair
4. Perform a swap test using the Porsche System Tester.
To do this, select >> PSM control unit >> Maintenance/repairs ]] Hydraulic swap test [[.
5. Calibrate the pressure sensor using the Porsche System Tester.
To do this, select >> PSM control unit >> Maintenance/repairs >> PSM sensor calibration >> Next ]] Pressure sensor calibration [[.
The safety code is displayed in the Porsche System Tester under >> PSM ]] Actual values [[.
6. Calibrate the combination sensor using the Porsche System Tester.
To do this, select >> PSM control unit >> Maintenance/repairs >> PSM sensor calibration >> Next ]] Calibrate axial acceleration sensor [[ Calibrate lateral acceleration sensor >>.
7. Code the hydraulic unit using the Porsche System Tester.
To do this, select >> Coding/adaptations >> Automatic coding with coding rules >> and then select Next to start the coding process.
The country coding must be strictly observed.
8. Perform a function test.
During the test drive, perform at least one ABS control operation, taking the road conditions into consideration.
Read out the fault memory. There must not be any faults stored.