Vacuum Pump: Service and Repair

Instructions and Function Description







As of the 2001 model, a sucking jet pump -1- is installed in Tiptronic vehicles!

The sucking jet pump -1- is permanently linked to the hoses -connection A/B/C- and, if replacement is necessary, the entire unit must be replaced!

In order to guarantee the accessibility of the sucking jet pump, especially for installation purposes, the intake pipe centre piece and the throttle body (together) must be removed!







The sucking jet pump -1- helps to increase the engine vacuum, connection -A-, required for the brake booster, especially during the engine warm-up phase.

Function: By bypassing the throttle -D- (bypass around the throttle from connection -B- to connection -C-), the rate of flow and so the vacuum are increased locally by the sucking jet pump -1-. This greater vacuum is applied to the brake booster connection -A-.


Preliminary Work


1. Cover the vehicle with protective covers in the rear area in such a way that the body can not be damaged.
2. Move convertible top to service position. To do this:
- Open the convertible top until the convertible-top compartment lid is half open.
- Detach cloth covering. Disengage the rear strip on the left and right sides of the cloth covering in downward direction.
- Detach tension cables. Press the ball socket of the tension cable out of the ball head of the adjusting piece on the left and right.
- Move convertible top to service position. To do so, press the tension bow of the convertible top towards the main bow, until it reaches its locking point (press the convertible top forwards until it engages).


Removing Sucking Jet Pump


NOTE: In order to guarantee the accessibility of the sucking jet pump, especially for installation purposes, the intake pipe centre piece and the throttle body (together) must be removed!


1. Remove ignition key.


CAUTION:
Danger of damage!
Pay attention to the position of electrical leads and hoses in the area of the sucking jet pump and the hoses (left/right and above/below)!
Lay the hoses and leads in the same position as before removal!







2. Disengage the cable -2- and then unlock and disconnect the hose -3- on both sides. Remove the intake pipe centre piece and the throttle body -4-. To do so, undo the hose clamps -arrows- and the fastening nut -5-.







3. Disconnect the leads (3 connections) -A, B, C- from the sucking jet pump -1-. To do this:
- Undo the screw (M6) from the clamp and remove the clamp -arrow-.
- Pull off lead -B-.
- Remove leads -A and C-. To do so, remove the circlip and then unlock the connection and pull off the lead at the same time.







NOTE: The circlip -arrow- is present on both the lead for the brake booster and on the lead behind the throttle!


Installing New Sucking Jet Pump







1. Install in reverse order.
2. Install new sucking jet pump. Observe the correct positioning of the leads.
3. Install the intake pipe centre piece together with the throttle body.
4. Start the engine and check the intake system for leaks.
5. Check function of brake booster.
6. Fit convertible top again.