Removing brake booster
Installation Location:
- During assembly work on hydraulic connections, the electrical plug connections on the hydraulic unit must always be connected. This prevents the plug connections on the hydraulic unit and the inside of the connectors being splashed with brake fluid or water.
- Damp connectors must be wiped dry before disconnection.
- Brake fluid on electrical contacts (even thinned brake fluid) leads to corrosion and may cause faults in the system.
The brake master cylinder is located on the left in the engine compartment, under the cowl panel cover -arrow- , together with the brake booster. See Fig 2.
- Brake lines are to be sealed with suitable plugs.
- To catch escaping brake fluid, place a cloth under the brake booster.
1. Push both connectors -arrows- on the plenum panel (oxygen sensor cable) from the bracket. See Fig 3.
2. Open the cable clip on the plenum panel and loosen the cable.
3. Remove left plenum panel partition.
4. Partly remove the brake master cylinder (brake fluid reservoir) → 471519 Removing and installing brake master cylinder - chapter on "removing" .
5. Disconnect the vacuum line on the brake booster.
6. Disconnect the connector from distance sensor of the brake booster -arrow- . See Fig 4.
7. Unclip the cable over the brake booster from the holders -arrows- and pull upwards. See Fig 5.
8. Unclip the brake line to left front wheel out of the bracket underneath the relay carrier.
9. Remove the brake master cylinder → 471519 Removing and installing brake master cylinder - chapter on "removing" .
10. Loosen two M6 screws on the lower closing panel -arrows- (upper screw head covered) (shown here when fitting the brake booster, relay carrier removed). See Fig 6.
- If the rubber bushes stick to the holders in the plenum panel when removing the relay carrier, these must be fitted in the openings provided before being inserted again.
11. Release the relay carrier in the plenum panel and hinge it to one side. To do this, unclip the six plugs in the rear section of the relay carrier ( -arrow- and right marking). See Fig 7.
12. Remove the cover under the dashboard on the driver's side in the passenger compartment. Refer to 70 02 19 Removing and installing front cover (engine compartment) - as of MY 2003 (All Models) .
13. Pull off connector of stop light switch -arrow- and remove the complete holder. Refer to 94 36 19 Removing and installing brake light switch - as of MY 2003 (All Models) . See Fig 8.
- When loosening the pushrod of the brake booster with the unlocking tool T10189 from the pushrod of the pedal, the tool must first be inserted and then the brake pedal pulled out into the passenger compartment.
14. Release brake pedal from pushrod -arrow- of brake booster with unlocking tool. Refer to 46 05 19 Removing and installing brake pedal - as of MY 2003 (All Models Except Cayenne S TIO Titan) . See Fig 9.
15. To do this, insert the unlocking tool T10189 from below into the bush on the brake pedal -arrow- . See Fig 10.
16. Remove the four M8 lock nuts on the brake booster in the passenger compartment.
17. Remove front left wheel housing liner.
18. Disconnect the brake line in the wheel housing on the intermediate piece -arrow- and seal with suitable plugs. See Fig 11.
19. Remove both clips for the air-conditioning lines in the plenum panel.
20. Pull the brake lines to the brake master cylinder and left front wheel carefully forward and press the air-conditioning lines down. Make sure that the boot on the brake booster -arrow- does not get stuck in the duct to the passenger compartment. See Fig 12.
21. Carefully pull out the brake booster -direction arrow- to the front. See Fig 13.