Contents: Removal - Early Mecatronic Hydraulic… ↳ Installation - Early Mecatronic… ↳ Removal - Late production Mecatronic… ↳ Installation - Late production… ↳ Removal - Bosh Hydraulic Modulators ↳ Installation - Bosh Hydraulic… ↳
Note: If any ABS component is faulty, the entire hydraulic modulator unit must be replaced. With the exception of the relay box (paragraph 22) spare parts for this system are not supplied.
1. Models produced before 1997 are equipped with a Mecatronic hydraulic modulator, models produced since 1997 are equipped with a Bosh 5.3 hydraulic modulator. Mecatronic hydraulic modulators are divided into two types depending on the time of their production: early and late production. The procedures for removing and installing all hydraulic modulators have much in common.
Removal - Early Mecatronic Hydraulic Modulators
2. Release both pressures (paragraph 19).
Models with V-shaped 6-cylinder engines
3. Remove the lower trim panel from the driver's side fascia. Then, in the driver's footwell, remove the pedal box assembly mounting nuts and lower the pedal box assembly as far as possible.
4. On models with air conditioning, contact your dealer to depressurize the system and remove the refrigerant. Disconnect the lines (if necessary) from the hydromodulator installation area. Caution: Do not disconnect the air conditioning line if the system is charged with refrigerant (chapter 3 paragraph 12).
5. Remove the bolts and brake booster brackets from the engine compartment.
Right hand drive models
6. Ask an assistant to press and hold the brake pedal. Pull out the elastic retainer and remove the pin securing the servo booster pushrod to the pedal connecting rod.
7. Remove the vacuum servo booster and take it out of the engine compartment.
Left hand drive models
8. Unscrew the nut securing the pedal pivot to the servo booster pushrod from inside the passenger compartment. The nut is located near the top of the pedal and can be unscrewed through a special access hole. To improve access, first remove the lower part of the trim from the front panel.
9. Remove the vacuum servo booster together with the pushrod and remove this unit from the engine compartment. Be careful not to damage the rubber bushing in the bulkhead.
All models
10. Disconnect the remaining brake lines from the ABS hydraulic modulator. To do this, unscrew the connection nuts and pull out the pipes. Slightly bend the pipes away from the hydraulic modulator so that it can be removed.
11. Disconnect the hydraulic modulator electrical connectors. To disconnect the main 22-pin electrical connector, press the lock, tilt the connector plug and pull it out.
12. Unscrew the pump mounting nut and the hydraulic modulator mounting nuts.
13. Lift the ABS hydraulic modulator from its left side, then tilt the BK unit so that it comes out of the right support. Be careful not to lose the bracket studs and the insulator ring.
Installation - Early Mecatronic Hydromodulators
14. Install the insulator ring onto the end of the pump and install the cover onto the insulator ring.
15. Install the hydraulic modulator in its place (right side first).
16. Install the right bracket studs onto the insulators.
17. Lower the hydraulic modulator left side onto the bracket. Then install and tighten the pump mounting nut.
Left hand drive models
18. Install the vacuum servo booster and push rod onto the bulkhead bracket so as not to damage the rubber bushing.
19. Insert the push rod into the pedal pin and tighten the nut.
20. Install the lower part of the front panel trim if it was removed.
Right hand drive models
21. Install the vacuum servo booster and pushrod onto the bulkhead bracket.
22. Install the servo booster pushrod mounting pin and retainer to the pedal connecting rod.
All models
23. Connect the electrical connectors to the hydraulic modulator. Connect the brake lines to the hydraulic modulator and tighten the nuts. Install both pressure limiting valves (paragraph 20). On models with V-shaped 6-cylinder engines, restore the air conditioning system line connections and pump refrigerant into it.
Removal - Late production Mecatronic hydraulic modulators
24. Disconnect the negative battery cable (chapter 5A).
25. Remove the air cleaner and intake duct (chapter 4A). On 4-cylinder models, remove the intake air duct chamber.
26. Disconnect the electrical connector of the brake fluid level sensor in the reserve reservoir. Disconnect the clutch fluid supply hose from its bracket. Move the hose to the side without disconnecting it (if possible).
27. Unscrew and remove the brake fluid reserve reservoir cap. Cover the reservoir neck with plastic film and secure it with adhesive tape to minimize leaks when disconnecting the lines.
28. Loosen the master cylinder mounting nuts and carefully remove the cylinder from the vacuum servo booster without disconnecting the brake lines. Move the master cylinder to the left so that it rests on the top of the left suspension strut.
29. Unscrew the nuts of the servo amplifier and remove it from the partition.
Right hand drive models
30. Ask an assistant to press and hold the brake pedal. Pull out the elastic retainer and remove the pin securing the servo booster pushrod to the pedal connecting rod.
31. Remove the vacuum servo booster and take it out of the engine compartment.
Left hand drive models
32. Unscrew the nut securing the pedal pivot to the servo booster pushrod from inside the passenger compartment. The nut is located near the top of the pedal and can be unscrewed through a special access hole. To improve access, first remove the lower part of the trim from the front panel by disconnecting the diagnostic electrical connector.
33. Remove the vacuum servo booster together with the pushrod and remove this unit from the engine compartment. Be careful not to damage the rubber bushing in the bulkhead.
All models
34. Disconnect the hydraulic modulator electrical connector.
35. Place rags under the hydromodulator to catch any drips.
36. Disconnect the remaining brake lines from the ABS hydraulic modulator. To do this, unscrew the connection nuts and pull out the pipes. Slightly bend the pipes away from the hydraulic modulator so that it can be removed.
37. Unscrew the 4 bolts securing the hydraulic modulator bracket and remove it together with the brackets.
Installation - Late production Mecatronic hydraulic modulators
38. Installation - in the reverse order of removal. Restore the connections of the electrical connectors and pipes, tightening the fasteners to the required torque.
Removal - Bosh Hydraulic Modulators
39. Disconnect the negative battery cable (chapter 5A).
40. Remove the air cleaner and intake duct (chapter 4A). On 4-cylinder models, remove the air intake duct chamber. Remove the air cleaner bracket.
41. Disconnect the brake fluid level sensor electrical connector on the brake fluid reserve reservoir. Disconnect the clutch fluid supply hose from its bracket. Move the hose to the side without disconnecting it (if possible).
42. Unscrew and remove the brake fluid reserve reservoir cap. Cover the reservoir neck with plastic film and secure it with adhesive tape to minimize leaks when disconnecting the lines.
43. Loosen the master cylinder mounting nuts and carefully remove the cylinder from the vacuum servo booster without disconnecting the brake lines. Move the master cylinder to the left so that it rests on the top of the left suspension strut.
44. Unscrew the servo amplifier nuts and remove it from the partition.
Right hand drive models
45. Ask an assistant to press and hold the brake pedal. Pull out the elastic retainer and remove the pin securing the servo booster pushrod to the pedal connecting rod.
46. Remove the vacuum servo booster and take it out of the engine compartment.
Left hand drive models
47. Unscrew the nut securing the pedal pivot to the servo booster pushrod from inside the passenger compartment. The nut is located near the top of the pedal and can be unscrewed through a special access hole. To improve access, first remove the lower part of the trim from the front panel by disconnecting the diagnostic electrical connector.
48. Remove the vacuum servo booster together with the pushrod and remove this unit from the engine compartment. Be careful not to damage the rubber bushing in the bulkhead.
49. Loosen the power steering bracket mounting nuts located around the steering column at its base. Remove the bracket from the bulkhead.
50. On models with air conditioning, move the air conditioning pipe bracket to the side.
51. Remove the bolts and brackets from the sides of the servo amplifier.
All models
52. Disconnect the hydraulic modulator electrical connector.
53. Place rags under the hydromodulator to catch any drips.
54. Disconnect the remaining brake lines from the ABS hydraulic modulator. To do this, unscrew the connection nuts and pull out the pipes. Slightly bend the pipes away from the hydraulic modulator so that it can be removed.
55. On models with V-shaped 6-cylinder engines, unscrew the 4 bolts securing the ABS unit brackets and slide this unit together with the brackets forward.
56. Unscrew the 2 nuts and remove the hydraulic modulator from the mounting lug and brackets.
Installation - Bosh Hydraulic Modulators
57. Installation - in the reverse order of removal. Restore the connections of the electrical connectors and pipes, tightening the fasteners to the required torque.