Steering Gear: Service and Repair
WM 489055 Replacing power-steering gear
Tools
Preliminary work
Information
- The rack-and-pinion steering gear and power-steering pump must not be repaired or dismantled!
- Always replace the O-rings on hydraulic lines!
- Ensure absolute cleanliness at all times!
- The reservoir must always be replaced if individual or multiple components, such as the tandem pump, PDCC valve blocks (FA/RA), PDCC anti-roll bars (FA/RA) are replaced.
- If system faults still occur after replacing a component (another component is defective), the reservoir does not have to be replaced again.
- Steel flexi-pipes must not be kinked or crushed.
- Observe safety requirements! -> 4303AW Safety Requirements for Porsche Dynamic Chassis Control (PDCC) Service Precautions
Information
- Fix steering wheel with wheels in straight-ahead position (engage steering column lock or clamp steering wheel in centre position with steering wheel holder). If this is not done, the airbag contact unit will have to be put in the centre position after installation of the steering gear -> 945019 Removing and installing steering column switch Service and Repair.
- Before the feed and return lines are loosened, place a suitable container underneath to collect steering fluid.
- Wear protective goggles and gloves.
1. Remove wheel -> 440519 Removing and installing wheel - section on "Removing" Removal and Replacement.
2. Remove engine guard -> 108019 Removing and installing engine guard - section on "Removing" 108019 Removing and installing engine guard.
3. -Wheel housing liner- must be partly removed -> 505619 Removing and installing front wheel housing liner - section on "Removing" Service and Repair.
Partly removing wheel housing liner
Removing
Removing steering gear
Installation position of steering gear
Information
- Fix steering wheel with wheels in straight-ahead position (engage steering column lock or clamp steering wheel in centre position with steering wheel holder). If this is not done, the airbag contact unit will have to be put in the centre position after installation of the steering gear -> 945019 Removing and installing steering column switch Service and Repair.
- Before the feed and return lines are loosened, place a suitable container underneath to collect steering fluid.
- Wear protective goggles and gloves.
1. Remove the outer tie rod joints with the ball joint puller T10187. When pressing out, screw lock nut on flush (protects the ball joint thread).
2. Remove the fastening screws -arrows- from the heat shield (steering gear/steering shaft). If the vehicle is a Cayenne with Servotronic, pull off the connector.
3. Remove fastening screw from the universal joint of the steering shaft -arrow- (push universal joint slightly upwards).
4. Remove the -heat shield- for the rear transmission mount.
Heat shield for rear transmission mount
5. Release rear mount of front-axle drive (right-hand side of vehicle). Lift the front axle drive with a suitable jack -see picture- (use a wooden block or rubber base to prevent slipping). Remove fastening screw and lift the front-axle final drive just enough to access the bearing eye above the bolting point of the front axle carrier (do not press the cardan shaft into the stop).
6. Re-insert the fastening screw -arrow- (better access). The drive remains in the raised position and the jack can be removed.
7. Release the supply and return lines -arrows- (collect steering fluid in a suitable container). Close off the lines and any open threaded bores with suitable stoppers.
8. Remove the fastening screws on the steering gear -arrows-.
9. For easier removal of the steering gear, loosen the fastening nut on the coolant hoses. Then unclip coolant hoses from brackets and lay them upwards -see picture- (cut-away view of steering gear shown here).
10. Remove heat shield for the right steering boot.
11. Push the steering gear -see picture- to the right, out of the subframe mounting points, and turn it to the rear.
12. Turn the steering gear -arrow- to the rear by approx. 90-100 degrees.
13. Unclip the coolant hoses in the wheel housing from the fastening clip. Then, carefully push the steering gear to the right and remove it by pulling it down through the chassis subframe.
Installing
Installing steering gear
WARNING
Steering-angle sensor not calibrated or calibrated incorrectly
- Unexpected vehicle handling
- Steering-angle sensor does not function
- Malfunction in steering-angle sensor
-> After working on wheel suspension parts, when replacing the steering-angle sensor and after changing the wheel alignment values, calibrate the steering-angle sensor using PIWIS Tester II 9818.
-> Keep the front wheels in straight-ahead position on the measuring platform during calibration.
-> Check the actual value of the steering-angle sensor after suspension alignment where no changes were made to the wheel alignment values.
Information
- When topping up or filling in Pentosin, make sure that it does not come into contact with the coolant hoses. To avoid overflow caused by overfilling, observe the instructions -> 48 Test and assembly work on power steering.
- If coolant hoses come into contact with Pentosin, clean them thoroughly with water IMMEDIATELY!
- Replace visibly swollen coolant hoses.
Installation position of steering gear
After fitting the pressure lines, fill steering hydraulics with Pentosin CHF 202 and bleed the steering system -> 48 Test and assembly work on power steering.
Replace all elastic bolts and lock nuts.
Tighten all threaded connections to the specified tightening torques -> 48 Tightening torques for steering.
Check and/or adjust toe-in -> 44 Suspension alignment, complete.
Calibrate steering-angle sensor -> 456019 Installing and removing steering-angle sensor Testing and Inspection.
Information
Installation is performed in reverse order.
Replace fastening screw of steering shaft whenever it has been removed. Ensure it is fitted correctly. Insert fastening screw (in correct position, not from the threaded side).
Always replace O-rings on pressure and intake pipes.
Push on universal joint (steering shaft) in correct position, with steering gear and steering wheel or airbag contact unit (spiral spring) in centre position. When doing this, only place steering transmission screws in position (to facilitate assembly when pushing universal joint on). After the fastening screws on the steering have been tightened, push the universal joint on as far as it will go. When fitted correctly and tension-free, the universal joint may be at a maximum distance -arrows- of 4 mm from the outermost edge of steering gear dust boot.
Replace steering gear fastening screws.
Screw threads must be clean and free of grease.
Ensure that no damage (scoring or similar damage) is caused to the steering rack.
If the tie rods are to be re-used, remove them from the removed steering transmission and fit them on the new steering transmission. Fit new sealing rings -arrow- on the steering gear.
Information
- The left clamp of the joint boot must be clamped so that the clamp lug -arrow- is in line with the steering pinion.
- The right clamp of the joint boot must be clamped so that the clamp lug -arrow- points horizontally with the front axle carrier (suspension subframe) in the direction of travel.
- Failure to do this can lead to constrictions on the left-hand side in the vicinity of the feed and return lines and on the right-hand side in the vicinity of the heat shield.
Fit the joint boot (not twisted) and secure with new clamps -arrow- (use pliers for hose clamp NR.74, Workshop Equipment Manual, commercially available tools).
Check the joint boot is not worn (cracks, slots) and that sealing faces are clean.
When fitting the ball joints, ensure that the conical seats are clean. Remove dirt or grease on conical seats, e.g. with a lint-free cloth. Do not use cleaning agent/solvent.
Observe airbag safety instructions -> 69 Safety instructions when working on vehicles with airbag and seat-belt pretensioners.
Install airbag unit for driver -> 695819 Removing and installing driver's airbag unit - section on "Installing" 695819 Removing and installing driver's airbag unit
Observe notes on steering-gear centre position in the section on front track adjustment in Alignment -> 44 Suspension alignment, complete.
Calibrate steering-angle sensor -> 456005 Initialising and calibrating steering-angle sensor Testing and Inspection.
Observe correct tightening torques -> 48 Tightening torques for steering.