Audi A6 Typ 4G: Subframe with Steering Gear, Removing and Installing
Special tools and workshop equipment required
- Torque Wrench 1331 5-50Nm -VAG1331-
- Torque Wrench 1332 40-200Nm -VAG1332-
- Engine and Gearbox Jack -VAS6931-
- Tensioning Strap -T10038-, quantity: 2
- Engine/Gearbox Jack Adapter - Wheel Hub Support -T10149-
- For a vehicle with air suspension Vehicle Diagnostic Tester
Removing
- Place the vehicle on a hoist. Refer to → Chapter "Raising and Lowering with Open and Closed Air Suspension System".
- For vehicles with an air suspension system, bleed the air suspension system. Refer to → Chapter "System, Venting or Filling".
- Remove the engine cover.
- Support the engine completely using the Engine Support Bridge. Refer to → Engine Mechanical, Fuel Injection and Ignition; Rep. Gr.10; Subframe Mount; Engine, Supporting in Installed Position.
- Remove the front wheels.
- Remove the noise insulation -1 and 2-. Refer to → Body Exterior; Rep. Gr.66; Noise Insulation; Noise Insulation, Removing and Installing.
- Remove the left and right front wheel housing liners. Refer to → Body Exterior; Rep. Gr.66; Wheel Housing Liner; Front Wheel Housing Liner, Removing and Installing.
- Remove the nuts -3- and remove the cover -2- (if equipped) from the right and left drive axle.
- Tip the top of the cover -2- toward the outside and guide it downward by the seam -1-.
- Remove the left and right wheel spoiler. Refer to → Body Exterior; Rep. Gr.66; Wheel Housing Liner; Overview - Front Wheel Housing Liner.
- Disconnect the left and right connector -1- from the vehicle level sensor (if equipped) and remove the clip -arrow-.
- Remove the right and left clamps for the vehicle level sensor wires from the subframe.
- Remove the connector -1- for the vehicle signals (CAN bus and terminal 15) from the Power Steering Control Module -J500-.
- Release the safety mechanism -arrow-, push the retainer downward and disconnect the connector -2- for the voltage (terminal 30) from the Power Steering Control Module -J500-.
- Free up the clip -arrow-, disconnect the connector -1- and free up the electric wire.
- Remove the remaining clips -arrows- on the crossbrace and free up the wiring harness.
Note
Ignore Items -1 through 5-.
- Open the clip -arrow- on the left rear subframe and free up the wiring harness.
- Turn the steering wheel so that the wheels are in the straight-ahead position and then tape it secure -arrow- so that it cannot turn.
Note
- Be sure to use tape that will not leave behind any residue when it is removed.
- Be careful not to turn the steering wheel during the repair because the Airbag Spiral Spring/Return Spring with Slip Ring -F138- can become damaged.
- Remove the bolt -arrow-.
- Remove the universal joint -1- from the steering gear -2- and support the steering intermediate shaft so that it cannot fall.
- Remove the right and left nuts -1- and bolts -2- and remove the heat shield upper section -3-.
- If equipped remove the Transmission Fluid Cooling Valve -N509-. Refer to → Engine Mechanical, Fuel Injection and Ignition; Rep. Gr.19; Coolant Pump/Thermostat; Coolant Valve, Removing and Installing.
- For vehicles with an intermediate flange -1-, remove the bolts -2 and 3- and free up the intermediate flange with the hoses still connected.
- Tie up the left and right wheel bearing housings using the Tensioning Strap -T10083--1-, as illustrated.
Note
To prevent the joints on the upper control arm from being damaged, support the wheel bearing housing.
- Remove the left and right control arms. Refer to → Chapter "Control Arm, Removing and Installing".
- Remove the nut from the left and right guide link joint pins enough so it is flush with the joint pin threads. Counterhold the joint pins if necessary.
- Press the guide link joint pin off the conical seat using the Puller - Ball Joint -T40042-.
Note
- Be careful not to damage CV boot in the process!
- Make sure that both puller lever arms are parallel to each other when using greatest force.
- Separate the left and right guide link from the wheel bearing housing. Be careful not to damage the CV boot on the guide link joint pin.
- Remove the threaded connector -1- for the right and left coupling rods on the shock absorber fork.
- Disconnect and free up the connectors -1- for the Right Electrohydraulic Engine Mount Solenoid Valve -N145- and -2- and for the Left Electrohydraulic Engine Mount Solenoid Valve -N144-.
Applies to Audi RS6
- Remove the nut -arrow-, free up the coolant pipe -1- and push it slightly to the side.
- Remove the bolt -arrow- and free up the wiring harness.
Applies to Vehicles with a 6- or 8-Cylinder Engine
- Remove the bolts -arrows- and the left lower front longitudinal member -1-.
- Remove the nuts and bolts -arrows- and free up the Ground (GND) cable -1- and the electric wire -2-.
- Remove the right lower front longitudinal member.
- Loosen the hose clamps -arrows-, then clamp off the coolant hoses with the Hose Clamps - Up To 25mm -3094- and remove the hoses.
- Disconnect the left and right connectors -1 and 2-.
- Remove the connector -arrow- from the mount, disconnect it, and then guide it through the subframe.
Continuation for All
- Remove the nuts -1 and 2-, if necessary, and move the GND cable -arrow- to the side.
- Remove the right and left clip -arrow- from the engine mount bracket and free up the wires and the metal bracket -1-.
- There is also a wire attached to the rear engine bracket on the left, depending on the engine type.
- Support the subframe using the Engine and Gearbox Jack -VAS6931- and a piece of hard wood, as shown.
- Remove the bolt -arrow- for the left and right engine mounts.
- Mark the location of the subframe to the longitudinal members using a felt-tip pen.
- Remove the left and right bolts -1, 2 and 3- from the subframe diagonally and in steps.
- Lower the subframe using the Engine and Gearbox Jack -VAS6931-.
Note
Make sure there is enough clearance for the electric lines when lowering the subframe.
- Replace the attachments later if necessary.
Installing
Install in reverse order of removal. Note the following:
WARNING
Pull on the -Item 1- steering intermediate shaft to make sure it is installed correctly with the bolt installed. Tighten the bolt -Item 1-.
Note
Perform a pre-adjustment on the subframe if it is being replaced or if it had to be removed in order to loosen the crossbrace.
Subframe Pre-Adjusting Procedure:
1 - Place the subframe over the head.
2 - Pre-install the steering gear and guide link (tighten the bolts hand-tight).
3 - Move the arms -1 and 2- to adjust dimension -A- (the inner edges of the holes must match up with each other).
4 - Mount the crossbrace and tighten it to the rear bolting points. The crossbrace is now pre-adjusted.
5 - Tighten the steering gear.
6 - Tighten the crossbrace at the front 2 attaching points.
Dimension -A- = 599 mm
Note
- Bonded rubber bushings have a limited range of motion. Only tighten suspension bolts when vehicle is in curb weight or control position.
- Lift wheel bearing in control position. Refer to → Chapter "Wheel Bearing in Control Position, Lifting Vehicles with Air Suspension" or → Chapter "Wheel Bearing in Curb Weight, Lifting Vehicles with Coil Spring".
- Position the subframe on the body at the location marked.
- Tighten the subframe bolts diagonally.
WARNING
All bolts and nuts must be tightened properly before driving the vehicle!
- To determine if an axle alignment is required, see Table. Refer to → Chapter "Evaluating Need for Axle Alignment".
- On vehicles with automatic head lamp range control, perform headlamp basic setting. Refer to → Electrical Equipment; Rep. Gr.94; Headlamp; Headlamp, Adjusting.
- If the Level Control Sensor is removed or installed on a vehicle with air suspension or if the linkage was loosened, the control position must be programmed again by starting the correct program on the Vehicle Diagnostic Tester in Guided Functions.
- If the control position was reprogrammed on vehicles with lane assist, the Camera Control Module -J852- must be calibrated again. Refer to → Chapter "Driver Assistance Systems Front Camera, Calibrating".
