Vacuum Brake Booster: Service and Repair

Power Vacuum Brake Booster Replacement (4.6L)

Removal Procedure




1. Place the vehicle on a flat surface.
2. Block the front wheels.
3. Apply the parking brake.
4. To allow access for the removal of the vacuum brake booster, position the gearshift lever into the lowest gear.
5. Remove the air cleaner assembly. Refer to Air Cleaner Assembly Replacement (Service and Repair).
6. Disconnect the fuel vapor lines in front of the brake booster.

* For the lines that have the plastic connectors, refer to Plastic Collar Quick Connect Fitting Service (Plastic Collar Quick Connect Fitting Service).
* For the lines that have the metal connectors, refer to Metal Collar Quick Connect Fitting Service (Metal Collar Quick Connect Fitting Service).




7. Remove the master cylinder nuts (3).

Note: Do not disconnect the brake pipes from the master cylinder.

8. Disconnect the master cylinder (1) from the brake booster (2) and position forward.
9. Disconnect the shift control cable from the shaft lever pin and position it out of the way. Refer to Automatic Transmission Range Selector Cable Replacement - Console (Service and Repair).




10. Disconnect the vacuum check valve (2) from the vacuum booster.
11. Remove the left closeout insulator panel. Refer to Instrument Panel Insulator Panel Replacement - Left Side (Instrument Panel Insulator Panel Replacement - Left Side).
12. Remove the left knee bolster. Refer to Driver Knee Bolster Replacement (Driver Knee Bolster Replacement).
13. To access the left lower brake pedal to vacuum brake booster mounting nut, remove the steering column mounting nuts. Refer to Steering Column Replacement (Steering Column Replacement).
14. Lower the steering column and support with heavy mechanics wire or equivalent.




15. Remove the power vacuum brake booster pushrod retaining clip (2) from the brake pedal.
16. Remove the spacer (3).
17. Disconnect the power vacuum brake booster pushrod from the brake pedal.




18. Remove the power vacuum brake booster nuts (1).
19. Raise the vehicle. Refer to Lifting and Jacking the Vehicle (Description and Operation).




20. Support the front frame with jack stands.
21. Loosen the left side frame bolts. Refer to Drivetrain and Front Suspension Frame Replacement (3.9L) (Service and Repair).
22. Lower the left side frame 51-76 mm (2-3 in) to gain clearance to remove the brake booster. Refer to Drivetrain and Front Suspension Frame Replacement (3.9L) (Service and Repair).




23. Remove the power vacuum brake booster from the vehicle.

Note: Do not reuse the power vacuum brake booster gasket if damaged.

24. Remove the power vacuum brake booster gasket.
Inspect the power vacuum brake booster gasket and replace, if necessary.

Installation Procedure




1. Install the power vacuum brake booster gasket to the booster.
2. Install the power vacuum brake booster to the vehicle.
3. Install the front frame. Refer to Drivetrain and Front Suspension Frame Replacement (3.9L) (Service and Repair).
4. Lower the vehicle.

Caution: Refer to Fastener Caution (Fastener Caution).




5. Install the power vacuum brake booster nuts (1) and tighten to 30 Nm (22 lb ft).




6. Apply a small amount of silicone brake lubricant to the brake pedal pivot.
7. Connect the power vacuum brake booster pushrod to the brake pedal.
8. Install the spacer (3) to the brake pedal.
9. Install the power vacuum brake booster pushrod retainer clip (2) to the brake pedal.
10. Install the power vacuum brake booster pushrod retaining clip bolt and tighten to 7 Nm (62 lb in).
11. Install the steering column. Refer to Steering Column Replacement (Steering Column Replacement).
12. Install the left knee bolster. Refer to Driver Knee Bolster Replacement (Driver Knee Bolster Replacement).
13. Install the left insulator panel. Refer to Instrument Panel Insulator Panel Replacement - Left Side (Instrument Panel Insulator Panel Replacement - Left Side).




14. Install the shift control cable to the shift cable bracket. Refer to Automatic Transmission Range Selector Cable Replacement - Console (Service and Repair).
15. Position the gearshift lever into park.




16. Install the power vacuum brake booster check valve (2) to the brake booster.
17. Install the master cylinder to the brake booster. Refer to Master Cylinder Replacement (Master Cylinder Replacement).
18. Connect the fuel vapor lines in front of the brake booster.

* For the lines that have the plastic connectors, refer to Plastic Collar Quick Connect Fitting Service (Plastic Collar Quick Connect Fitting Service).
* For the lines that have the metal connectors, refer to Metal Collar Quick Connect Fitting Service (Metal Collar Quick Connect Fitting Service).