Alignment: Service and Repair
Suspension alignment, complete
The suspension alignment of the Cayenne differs insignificantly to that of conventional suspension alignment. This involves the vehicle height adjustment, the wheel-load difference from left to right, special tools and corrections to wheel alignment.
Modified -quick-clamping holders- (for fastening the measured-value pickups on the wheels) are used for the Cayenne. These measured-value pickups are positioned (with the claws first) centrally in the centre of the rim and tautened clockwise in the rim with the straining ring. The order number for the new clamping units will be included in the Workshop Equipment Manual.
The quick-clamping holders present (old version) can be retrofitted by replacing the clamping units on the left and right.
Vehicle height/wheel load
In the case of the Cayenne, the body is supported by suspension subframes at the front and rear axles. This means that bumps in the road are absorbed by the chassis and do not reach the body. In certain cases (e.g. after removal and installation of power unit) the alignment values may not be reached. In such cases, the suspension subframe may be shifted slightly.
The suspension alignment of the Cayenne differs insignificantly to that of conventional suspension alignment. This applies to both the front and the rear axles.
The varying strength spring shim, at the bottom between coil springs and spring seats (on the right and left spring struts on the front and rear axles) is not intended for changing the vehicle height but for compensating for differences in coil-spring load groups.
If the differences in wheel load are too large, the arrangement of the coil springs (same coil springs left/right) and the arrangement of the shims at the bottom (same shims at bottom left/right) must be checked. Only coil springs and shims with the same colour coding should be installed at bottom on left and right.
Due to varying trim variants (additional equipment) a maximum difference in wheel load of 40 kg from left to right is permitted per axle. This is partly the result of heavier components compared with standard equipment and partly results from additional components that are asymmetrically arranged.
Note!
^ In general, the following applies: Max. 40 kg wheel load difference left to right per axle! However, no more than 60 kg difference in total between front axle and rear axle!
^ This means: A maximum of 40 kg at one axle and a maximum of 20 kg at the other axle!
Special notes for vehicles with air suspension
^ If the vehicle is a Cayenne with air suspension, it must be adjusted to normal level. The vehicle normal level must be set from the low level. The vehicle may be aligned and adjusted in this position only.
^ If the control module or one of the level sensors was replaced, calibration must be carried out with the Porsche System Tester.
Adjust vehicle to normal level:
^ Stop vehicle and apply brake.
^ Close vehicle doors.
^ Tap the right-hand rocker switch on the centre console in the appropriate direction until vehicle has reached low level. Then set the vehicle normal level. The middle indicator light next to the rocker switch is on permanently. If a further indicator light should come on, a different level is adjusted.
To avoid controlling the level of air suspension during the alignment, switch the level control off during alignment and switch it on again after work has been completed.
Wheel-alignment corrections
Rear axle
Warning! Danger of injury and damage to property due to malfunctions in the PSM control range if the steering angle sensor is not calibrated or is calibrated incorrectly!
^ Calibrate steering angle sensor with wheels in straight-ahead position with the Porsche System Tester!
^ The steering angle sensor actual value must be checked after a suspension alignment which resulted in no changes being made to the wheel alignment values!
^ The kinematic toe-in and caster cannot be adjusted!
^ Camber and toe can be adjusted via eccentrics!
Front axle
Warning! Danger of injury and damage to property due to malfunctions in the PSM control range if the steering angle sensor is not calibrated or is calibrated incorrectly!
^ Calibrate steering angle sensor with wheels in straight-ahead position with the Porsche System Tester!
^ The steering angle sensor actual value must be checked after a suspension alignment which resulted in no changes being made to the wheel alignment values!
^ The steering angle sensor must be calibrated if the previous wheel alignment values (on rear and/or front axle) were changed!
^ After adjusting the toe, the lock nuts on the track rods must be tightened to the prescribed tightening torque of 70 Nm (52 ft. lbs.)!
^ Use correct tightening torques!
General procedure for suspension alignment
Note! Carry out suspension alignment with an optical or electronic wheel alignment tester!
^ The measurement procedures should be taken from the operating instructions for the wheel alignment tester involved!
In order to exclude erroneous measurements, the following preconditions must be met before alignment and the following points should be given special attention:
^ Empty weight of vehicle, i.e. vehicle in running condition, fully tanked with tyre repair kit or spare wheel and tools.
^ Ballpoint and wheel-bearing play in order (wheel-bearing play cannot be adjusted).
^ Tyre pressure in accordance with regulations, fairly uniform tyre tread.
^ Quick-clamping holder for Cayenne (for the measured-value pickups) correctly secured to the wheels.
^ Receiving surfaces for the quick-clamping holder on the wheels must be clean and flat. Always check the levelling surface on the wheels precisely in particular before fitting the quick-clamping holders.
^ Strictly comply with maintenance intervals for measuring equipment and measuring platform. If the levelling of the measuring platform or of the measuring area is done in-house, levelling equipment is required. A hose level is inadequate!
^ Skilled handling of measuring equipment and measuring platform..
^ Sliding plates with transverse motion (rotary motion) at the rear axle are advisable.
^ Observe the Technical Literature of PAG, the manufacturer of the measuring equipment and the manufacturer of the measuring platform..
^ Do not treat measured values as a whole, but very critically in regard to driving dynamics, high-speed strength of the tyres, tyre wear and cost/benefit effects (time required for correction of insubstantial deviations). The toe values are of decisive significance for driving dynamics and tyre wear.
^ If the vehicle is measured front and rear, check and adjust the wheel alignment values at the rear axle first. Camber values at the front axle apply for the straight-ahead position of the wheels. Steering wheel and steering gear in centre position when toe is being adjusted.
^ Before wheel alignment values are adjusted at front and rear axles, it is recommended that the vehicle height be checked at the empty weight. Conclusions can then be drawn about wheel alignment values in the event of any suspension alignment that becomes necessary later.
Vehicle height (vehicle height check)
General
^ The vehicle height at front and rear axle is not adjustable.
^ The check points for the vehicle height can be found in the following description.
Preliminary work
1. To carry out height check, position ready-to-drive vehicle (fully tanked with tyre repair kit or spare wheel and tools) on a flat surface or on the measuring station. In the case of vehicles with air suspension, the normal vehicle level must be set. The vehicle normal level must be set from the low level. Normal level means: Start the engine so that the compressor is running. If there is sufficient air in the pressure tanks, the engine does not need to be started. Tap the right-hand rocker switch on the centre console in the appropriate direction until vehicle has reached low level. Then set the vehicle normal level. The middle indicator light next to the rocker switch is on permanently. If a further indicator light should come on, a different level is adjusted.
2. To avoid controlling the level of air suspension during the alignment, switch the level control off during alignment and switch it on again after work has been completed.
3. Compress vehicle at front and rear by approximately 25 mm 2-3 times and allow it to spring back freely.
Rear axle
The measurement is made from the wheel contact area to the bottom edge of the side member suspension subframe -A- (in front of drain bore at connection point control arm to suspension subframe).
Front axle
The measurement is made from the wheel contact area to the bottom edge of the side member -A- of front axle suspension subframe (between camber and caster eccentric).
Wheel alignment
Warning! Danger of injury and damage to property due to malfunctions in the PSM control range if the steering angle sensor is not calibrated or is calibrated incorrectly!
^ Calibrate steering angle sensor with wheels in straight-ahead position with the Porsche System Tester!
^ The steering angle sensor actual value must be checked after a suspension alignment which resulted in no changes being made to the wheel alignment values!
^ Only check or adjust wheel-alignment values when prescribed preconditions are met.
^ If the vehicle is measured front and rear, check and adjust the rear axle first.
^ After adjustment, tighten the appropriate screw connections with the prescribed tightening torque.
^ The steering angle sensor must be calibrated if the previous wheel alignment values (on rear and/or front axle) were changed.
Rear axle
1. Prepare vehicle for checking and/or adjustment of wheel alignment values.
2. Place front wheels on rotary table and rear wheels on rotary / sliding plates.
3. Compress vehicle at front and rear by approximately 25 mm 2-3 times and allow it to spring back freely.
Adjusting camber
Warning! Danger of injury and damage to property due to malfunctions in the PSM control range if the steering angle sensor is not calibrated or is calibrated incorrectly!
^ Calibrate steering angle sensor with wheels in straight-ahead position with the Porsche System Tester!
^ The steering angle sensor actual value must be checked after a suspension alignment which resulted in no changes being made to the wheel alignment values!
^ Specified tightening torque for fastening nut to camber eccentric -A- = 180 Nm (133 ft. lbs.)!
Camber is adjusted at camber eccentric -A- !
Camber eccentric -A-
- After loosening fastening nut, turn camber eccentric -A- appropriately.
Adjusting toe
Warning! Danger of injury and damage to property due to malfunctions in the PSM control range if the steering angle sensor is not calibrated or is calibrated incorrectly!
^ Calibrate steering angle sensor with wheels in straight-ahead position with the Porsche System Tester!
^ The steering angle sensor actual value must be checked after a suspension alignment which resulted in no changes being made to the wheel alignment values!
^ Specified tightening torque for fastening nut to camber eccentric -B- = 180 Nm (133 ft. lbs.)
Toe is adjusted at toe eccentric -B- !
Toe eccentric -B-
- After loosening the fastening nut, turn toe eccentric -B- appropriately.
Front axle
Adjusting camber
Warning! Danger of injury and damage to property due to malfunctions in the PSM control range if the steering angle sensor is not calibrated or is calibrated incorrectly!
^ Calibrate steering angle sensor with wheels in straight-ahead position with the Porsche System Tester!
^ The steering angle sensor actual value must be checked after a suspension alignment which resulted in no changes being made to the wheel alignment values!
^ Specified tightening torque for fastening nut to camber eccentric -A- = 180 Nm (133 ft. lbs.)!
Camber is adjusted at camber eccentric -A-.
Camber eccentric -A
Adjusting caster
^ Specified tightening torque for fastening nut to caster eccentric -B- = 180 Nm (133 ft. lbs.)!
Caster is adjusted at caster eccentric -B-.
Caster eccentric -B
Adjusting toe
Warning! Danger of injury and damage to property due to malfunctions in the PSM control range if the steering angle sensor is not calibrated or is calibrated incorrectly!
^ Calibrate steering angle sensor with wheels in straight-ahead position with the Porsche System Tester!
^ The steering angle sensor actual value must be checked after a suspension alignment which resulted in no changes being made to the wheel alignment values!
^ The steering angle sensor must be calibrated if the previous wheel alignment values (on rear and/or front axle) have been changed!=m
^ Tighten fastening nut (lock nut) at tie rod -at C- with 70 Nm (52 ft. lbs.) in connection with the -insert for dynamometric key-.
^ If the specified tightening torque has not been reached after alignment on the alignment platform (due to reasons of space), turn the steering to left and right and tighten the tie rod screws! Counter with open-ended wrench!
The toe is adjusted at the tie rod screws toe rod/tie rod end (ball joint) -C-.
Toe adjustment -C-
Preliminary work:
1. Check whether the steering wheel is displaced with respect to the steering gear.
2. To do this, centre the steering gear as described.
3. Turn wheels to the straight-ahead position.
4. Remove cover for underbody (transmission protection) and -heat insulation panel- from steering.
5. The -marking for steering centre position 1- is under the heat insulation panel at the front in the direction of travel, on the steering gear housing (pictured here on removed unit for easier comprehension, picture shows in direction of travel).
1 Marking steering centre position
2 Break-off remainder (retainer pin for new steering gears. Breaks off the first time the steering is used.)
^ No. -2- is remainder of desired breaking point of locking pin with new steering gears! This locks the steering gear in the centre position! After installation of a new steering gear, the lower part of the pin is sheared off at desired breaking point by turning the steering wheel.
6. Afterwards, if necessary, correct front wheel alignment until marking on steering housing (triangle) is aligned with marking lug -1- of driver.
If necessary, reposition the steering wheel.
Warning! A triggering of the airbag (malfunction in the airbag system) caused by improper work on airbag components cannot be ruled out! In the case of such a malfunction, an unsuitable steering wheel holder could cause injury or damage!
^ Use only steering wheel holders which do not project into the area of the airbag unit!
^ Observe safety regulations for airbag vehicles!
7. Clamp steering wheel in centre position with steering wheel holder.
Note!
^ Use only steering wheel holders which do not project into the area of the airbag unit!
^ If necessary, shorten guide rod at top!
8. Adjust toe at hexagon of tie rod(s) after releasing lock nut(s). The steering angle sensor must subsequently be calibrated by PSM.
Warning! Danger of injury and damage to property due to malfunctions in the PSM control range if the steering angle sensor is not calibrated or is calibrated incorrectly!
^ Calibrate steering angle sensor with wheels in straight-ahead position with the Porsche System Tester!
^ The steering angle sensor actual value must be checked after a suspension alignment which resulted in no changes being made to the wheel alignment values!
Specified tightening torque of fastening nut(s) (lock nut) -C- = 70 Nm (52 ft. lbs.).
Toe adjustment -C-
Toe-difference angle
The toe-difference angle is not adjustable.