Removal and Replacement
Hydraulic unit, replacing
Note! Never, under any circumstances, open the ABS hydraulic modulator. Reassembling it requires special equipment and facilities.
Preparations
- Ignition off.
- Place a rag under the ABS hydraulic modulator as protection against brake fluid spillage.
- Depress the brake pedal a few times so that no vacuum remains in the power brake booster.
- Clean the brake pipes terminals at the ABS hydraulic modulator and master cylinder.
- Disconnect the ignition cable from the ignition coil and its mountings on the air cleaner (ACL) housing.
- Remove the air cleaner (ACL) housing and air pre-heating intake hose.
On vehicles with turbocharged engines
Remove:
- The intake pipe between the air cleaner (ACL) housing and turbocharger (TC).
Locking brake pedal
- Raise the vehicle.
- Remove the protective cap from bleed nipple at the left front wheel.
- Connect the hose from the collection bottle.
- Open the bleed nipple and depress the brake pedal. Hold it down or lock the brake pedal in that position.
- Shut the bleed nipple.
Removing the bracket with the ABS hydraulic modulator
Remove:
- The brake pipes between the ABS hydraulic modulator and the master cylinder.
- Disconnect the brake pipes for the wheel brakes.
Immediately plug the brake pipes and terminals on the ABS hydraulic and the master cylinder to prevent dirt entering the system.
- Disconnect the control module connector by pressing in the catch on the rear edge of the cover (wheel arch side). Then carefully turn the cover upwards so that the lock catches.
Remove:
- The bracket mounting screws and lift up the bracket.
- Lift up the bracket and release the vacuum hose.
On vehicles with TRACS
- Lift up the bracket a little and move it forward.
- Remove the check valve with the vacuum hose from the power brake booster.
Removing the ABS hydraulic modulator from the bracket
Note! The ABS hydraulic modulator must be replaced as a complete unit. Never open the ABS hydraulic modulator under any circumstances. Reassembling it requires special equipment and facilities.
- Disconnect the pump motor connector from the control module.
- Remove the bracket and control module from the ABS hydraulic modulator.
Checking the ABS hydraulic modulator
- Check that the ABS hydraulic modulator is of the correct type depending on whether or not the car is equipped with TRACS. The difference is that the TRACS hydraulic modulator has seven valves to the control module instead of six.
Note! Never, under any circumstances, open the ABS hydraulic modulator. Reassembling it requires special equipment and facilities.
Installing the ABS hydraulic modulator
Note! The ABS hydraulic modulator is filled with brake fluid. It is important that the plugs are not removed until the brake pipes are to be connected.
- Check and install control module on the ABS hydraulic modulator according to Replacing the control module Service and Repair. Install the screws. Tighten to 1.8 Nm.
- Install the new ABS hydraulic modulator on the bracket and tighten the mounting screws. Tighten to 8 Nm.
- Hold the vacuum hose to one side and carefully install the bracket in the car.
- Connect the pump motor connector to the control module.
- Tighten the mounting screws to 8 Nm.
On vehicles with TRACS
Insert the vacuum hose between the bracket and ABS hydraulic modulator. Check that the check valve and rubber seal are intact. Connect the check valve to the power brake booster.
Installing the ABS hydraulic modulator, continued
- Connect the connector to the control module and the pump motor.
- Remove the plugs and connect the brake pipes to the ABS hydraulic modulator and master cylinder. Tighten to 14 Nm.
- Release the brake pedal.
- Install air cleaner (ACL) housing with intake pipe and air pre-heating hose.
- Connect the ignition cable to the ignition coil.
On vehicles with turbocharged engines
Install:
- The intake manifold between the air cleaner (ACL) housing and turbocharger.
Finishing work
- Bleed the brake system.
Clean up any spilled brake fluid using warm water and car shampoo.
Checking the function
- Read off any diagnostic trouble code (DTCs) stored in the control module and erase them.
- Switch off the diagnostic tool. Check that the ABS warning lamp stops flashing.
- Test drive the vehicle. Check the function of the brakes and that the ABS warning lamp stops flashes.
Warning! The ABS and EBD functions are not accessible when Volvo Diagnostics are activated. Great care should be taken when testing, there is a great risk of the wheels locking.