Installing Rear Spring Strut (Air Springs)

→ Secure the climbing aid to prevent it from slipping and tipping over.

→ Wear personal protective gear.

→ Do not raise the wheel suspension higher than the normal vehicle position (vehicle resting on wheels).

Information 

• All screws and threaded joints on the axle must be tightened in vehicle position. Vehicle position means: vehicle standing on its wheels or the wheel suspension is raised with a universal vehicle lift. Measurement -1- from the lower edge of the wing to the middle of the vehicle axle corresponds to vehicle position. The current height values can be found in →  4495TW ADJUSTMENT VALUES FOR SUSPENSION ALIGNMENT  . Always observe the following points!
  Fig 1: Checking Dimension 1 - Centre Of Wheel To Lower Edge Of Wing (Rear Axle)

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• On vehicles with air springs, the respective air spring must be bled using the Porsche System Tester  . → 4301IN BLEEDING AND FILLING THE LEVELLING SYSTEM 
• Screws and nuts are Geomet-coated and must not be greased  .

Information 

• When working on the air-spring strut, make sure that the air-spring strut does not become twisted  .
• The air-spring struts are pre-filled to approx. 2.5 bar overpressure ex-works  . If a new air-spring strut is installed, air can diffuse (escape) from the bellows of the air-spring strut as a result of storage times of varying duration. If the air-spring strut is removed from the transport packaging and installed without being filled, the bellows can fall into folds, thereby damaging the air-spring strut. For this reason, all air-spring struts must be re-filled prior to use. The procedure is described in detail in the course of the repair instructions. → 4301IN FILLING SPECIFICATION FOR AIR-SPRING STRUT 

Information 

• Do not remove air-spring strut from transport packaging until it has been filled. This will prevent damage to the inner bellows  .
• During assembly work, make sure that there are no pressure marks on the protective boot of the air-spring strut  .

Information 

• The air-spring strut must only be filled with the approved gasses, nitrogen or oil-free compressed air  .
• In some cases, up to 11 bar overpressure (upper tolerance, spring strut depressurized) is required to open the pressure control valve  .
• Fill the air-spring strut using 3 to 4 shots of pressure. Filling the air with individual pressure shots will prevent the air-spring strut from being filled with too much overpressure  .
• Do not fill the air-spring strut with overpressure of more than 2.5 bar  .

Information 

• Check the torque at the pressure control valve  . → 4X00IN TIGHTENING TORQUES FOR LEVELLING SYSTEM

Information 

• The pictures shown in this document may differ from the original  .

1. A new air-spring strut must be filled before it is fitted. → 4301IN FILLING SPECIFICATION FOR AIR-SPRING STRUT 

   A second mechanic is needed for installing the spring strut  .

2. Only raise the vehicle as far as required on the lifting platform so that a suitable jack can fit under the wheel bearing housing and a second mechanic can easily reach the luggage compartment floor with a small ladder. → Upper spring-strut mount 
3. Carefully fit the spring strut -1-  at the upper spring-strut mount.
4. When doing so, make sure that the pins -3-  of the rocker bearing -2-  fit exactly into the corresponding bore -4-  on the body.
   Fig 2: Identifying Upper Spring-Strut Mount

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5. Position the jack -2-  as a support under the spring strut -1-  and raise it as far as required -A-  until the installation position of the spring strut no longer changes.

   The rocker bearing must be flush with the body  .

   Fig 3: Installing Spring Strut

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6. The second mechanic -3-  must now climb onto a suitable pedestal -4-  , or small ladder and fit and tighten the top screws -1-  on the spring strut. Final tightening of the top fastening screws to the specified tightening torque is done in Step  11.

   When fitting the screws, make sure that they do not tilt and can be screwed in easily.

   Fig 4: Identifying Upper Spring-Strut Mount Screws

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7. Raise the vehicle → 4X00IN LIFTING THE VEHICLE .
8. Insert the spring strut into the wheel bearing housing with the help of the jack.
   Fig 5: Lifting Wheel Bearing Housing

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9. Fit lower spring strut -1-  with the wheel bearing housing -2-  and connecting link -4-  .

   To do this, insert the fastening screw -3-  through the components from behind and fit it. Tightening torque 90 Nm (67 ftlb.) +90 angular degrees 

   Fig 6: Identifying Spring Strut Screw (Air Springs)

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10. Plug in electric plug connection -1-  for the spring strut -A-  and lock it -a-  .
    Fig 7: Locating Electric Plug Connection For Rear Spring Strut (Air Springs)

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11. Fit the pressure line -1-  to the pressure-retaining valve -2-  using insert tool T10212 Insert tool T10212  (). Then clip pressure line into the retaining devices.
    Fig 8: Identifying Pressure Line For Rear Spring Strut

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12. Lower the vehicle.
13. Then fit fastening screws -1-  for the upper spring strut and tighten to the specified tightening torque. Tightening torque 50 Nm (37 ftlb.) +180°

    The tightening sequence -A, B, C, D-  must be strictly observed!

    Fig 9: Identifying Installation Sequence For Upper Spring Strut Screws

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14. Secure the caps -1-  on the top fastening screws for the spring strut at the front.
    Fig 10: Identifying Spring Strut Caps

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