Note: Whenever an ABS modulator adjuster bolt is slackened or removed, the bolt threads should be lightly coated with grease to prevent the possibility of bolt seizure. Take care not to contaminate surrounding components when applying the grease.

Note: Before starting work, refer to the warning at the beginning of Section 3 concerning the dangers of hydraulic fluid.

Right-hand side
Removal
1 Disconnect the wiring plug from the level warning switch in the master cylinder reservoir filler cap. Remove the cap.

2 Syphon out as much fluid as possible from the reservoir using an old battery hydrometer.

Do not drip the fluid onto the paintwork as it will act as an effective paint stripper.

3 Release the hose clip and disconnect the right-hand modulator fluid return pipe at the master cylinder reservoir (nearest to the vacuum servo unit) (see illustration).

21.3 Modulator fluid return pipes at master cylinder reservoir

A To right-hand modulator B To left-hand modulator

4 Jack up the front of the car and support it on stands (see “Jacking and Vehicle Support”).

5 Remove the belt break switch from the drivebelt cover by pushing it upward and carefully levering out the bottom edge. Pull the switch down, withdraw the switch arm from the opening in the cover and place the switch to one side.

6 Undo the two drivebelt cover retaining nuts and washers, and on later models (1987-on), the retaining bolt.

7 Withdraw the cover from the studs and remove it by moving it upwards to clear the oil filter.

8 Disconnect the two hydraulic pipes and hoses with the yellow bands at the pipe bracket on the transmission support crossmember (see illustration). Allow the remaining hydraulic fluid to drain into a suitable container.

21.8 Hydraulic pipe and hose unions (arrowed) at the pipe bracket on the transmission support crossmember

9 Slacken the modulator adjuster bolt, move the modulator to relieve the tension on the drivebelt then slip the belt off the modulator sprocket (see illustration).

21.9 Right-hand modulator adjuster and pivot bolts (arrowed)

10 Undo and remove the adjuster bolt and the modulator pivot bolt and withdraw the modulator from the engine compartment.

11 If required, disconnect the hydraulic hoses at the modulator after removal. Plug or tape over all pipe ends and orifices to prevent dirt ingress.

Refitting
12 If a new unit is being fitted check that it has a yellow arrow marked on its cover and a part number suffix “A” indicating a right-hand side modulator. Note that the units are not interchangeable from side to side.

13 Reconnect the modulator hydraulic hoses if applicable.

14 Locate the modulator on its mounting bracket, fit the pivot bolt and tighten it to the specified torque.

15 Slip the drivebelt over the modulator sprocket ensuring that it sits squarely in the sprocket teeth.

16 Move the modulator as necessary to tension the belt so that the belt deflection, under light finger pressure is 5.0 mm. Check this using a ruler at a point midway between the two sprockets.

17 With the belt tensioned correctly, tighten the modulator adjuster bolt. Before tightening, the adjuster bolt threads should be coated with grease - refer to the note at the beginning of this Section.

18 Reconnect the two modulator hydraulic pipes and hoses.

19 Refit the drivebelt cover and secure with the two nuts and washers, and the bolt (where applicable).

20 Engage the belt break switch arm upwards through the opening in the drivebelt cover then locate the switch in position. Pull the switch downwards to secure.

21 Lower the car to the ground.

22 Reconnect the modulator fluid return pipe to the master cylinder reservoir then fill the reservoir with fresh fluid of the specified type.

23 Bleed the hydraulic system (Section 23).

Left-hand side
Removal
24 Disconnect the wiring plug from the level warning switch in the master cylinder reservoir filler cap. Remove the cap.

25 Syphon out as much fluid as possible from the reservoir using an old battery hydrometer or a poultry baster. Do not drip the fluid onto the paintwork as it will act as an effective paint stripper.

26 Release the hose clip and disconnect the left-hand modulator fluid return pipe at the master cylinder reservoir (the one furthest away from the vacuum servo unit).

27 Jack up the front of the car and support it on stands (see “Jacking and Vehicle Support”). Remove the left-hand roadwheel.

28 Remove the engine splash shield from the inner wheel arch.

29 Remove the belt break switch from the drivebelt cover by pushing it upwards and carefully levering out the bottom edge. Pull the switch down, withdraw the switch arm from the opening in the cover and place the switch to one side.

30 Undo the three bolts, two at the top and one at the bottom securing the drivebelt cover to the modulator bracket. Remove the cover.

31 Disconnect the two hydraulic pipes and hoses with the white bands at the pipe bracket on the transmission support crossmember. Allow the remaining hydraulic fluid to drain into a suitable container.

32 Slacken the modulator adjuster bolt, move the modulator to relieve the tension on the drivebelt then slip the belt off the modulator sprocket (see illustration).

21.32 Left-hand modulator adjuster and pivot bolts (arrowed)

33 Remove the distributor cap, rotor arm and shield. Disconnect the left-hand belt break switch wiring at the multi-plug.

34 Undo and remove the adjuster bolt and the modulator pivot bolt and withdraw the modulator upwards out of the engine compartment.

35 If required, disconnect the hydraulic hoses at the modulator after removal. Plug or tape over all pipe ends and orifices to prevent dirt ingress.

Refitting
36 If a new unit is being fitted check that it has a white arrow marked on its cover and a part number suffix “C” indicating a left-hand side modulator. Note that the units are not interchangeable from side to side.

37 Reconnect the modulator hydraulic pipes if applicable.

38 Locate the modulator on its mounting bracket, fit the pivot bolt and tighten it to the specified torque.

39 Slip the drivebelt over the modulator sprocket ensuring that it sits squarely in the sprocket teeth.

40 Adjust the drivebelt tension as described in paragraphs 16 and 17, but use a suitable length of wood inserted through the steering tie-rod aperture in the inner wheel arch, to push on the modulator as necessary.

41 Reconnect the two modulator hydraulic pipes and hoses.

42 Refit the drivebelt cover and secure with the three bolts.

43 Refit the belt break switch as described in paragraph 20.

44 Refit the engine splash shield.

45 Refit the roadwheel and lower the car to the ground.

46 Reconnect the belt break switch wiring multi-plug then refit the shield, rotor arm and distributor cap.

47 Reconnect the modulator fluid return pipe to the master cylinder reservoir then fill the reservoir with fresh fluid of the specified type.

48 Bleed the hydraulic system as described in Section 23.