Tools required:
Trolley jack
Axle stands
22 mm spanner or ½ inch socket, ratchet
Torque wrench
Flat blade screwdriver,
Hammer
C spanner (Fig 3)
1 flat bar (approx. 200mm x 25mm x 8mm) for use as drift and/or pipe spanner
Copper slip or similar grease
Bilstein lock ring mounting tool (Fig 8 ref.14-244148 from Design 911).

Jack up front of car, remove road wheels and support vehicle with axle stands at front of wishbones.
Place jack underneath wishbone ball joint and raise strut until shock absorber is compressed – car will start to lift off axle stand when achieved.

  
Fig 1 Car supported on axle stands

Fold back lock tab on M14 nut on upper thrust bearing (Fig 2).

Fig 2  Upper Thrust Bearing

Using a C spanner (Fig 3) prevent the notched washer from turning and undo the nut with 22mm socket or spanner. Lower the jack and hence lower the strut. Caution - hold the strut during lowering to stop it falling against the wing and/or straining the flexible brake hose.

Fig 3  C Spanner

Once lowered, support the strut/hub assembly - a piece of 4x4 x 12 inch fence post works. I add a bungee from inner wing brake connection mount to strut.

Press down on the insert to remove it from the thrust bearing. If the existing insert is a gas shock, it will likely offer resistance; if just an oil shock it will lower more easily.
From inside the wheel arch, compress the shock absorber to remove the protective sleeve and rubber buffer (Fig 4).

Fig 4  Sleeve and Buffer

The insert lock ring will now be clearly seen, usually four notches (Fig 5). Remove the lock ring with either a suitable C spanner, pipe wrench or tap it around with length of flat bar and a hammer! It may be seized so a releasing spray or heat may help.

Fig 5  Exposed Boge Lock Ring

Lift out insert from the strut (Fig 6) which may need tilting outward to clear the wing.


Fig 6 Insert Removed
The new Bilstein insert comes with 2 types of lock rings - the internal thread ring is required - plus a protective sleeve and new 22mm nyloc nut (Fig 7).

Notes: There is no rubber buffer – it’s contained within the insert body. The small rubber washer is for transportation /packing purposes. It is not necessary to put oil in the strut body, although it may provide additional rust protection and cooling.

Before fitting the new insert, compress it several times to facilitate movement and lubricate internal seal. Additional lubrication can also be applied to the new lock ring seal before fitting.

Fig 7 Bilstein Components

Clean strut internal lock ring thread, apply grease to the new lock ring thread.
Screw lock ring into strut body to ensure threads run smoothly. Remove. Place insert into strut and secure with lock ring using Bilstein mounting tool (fig 8), C spanner or tap tight with bar and hammer.

Stated torque is 130 +/- 10 Nm – which is tight!
Apply grease to exposed threads to reduce corrosion.

Fig 8 Bilstein lock ring mounting tool

Note: The lock ring does not seat fully down onto the strut body, leaving about 5mm exposed thread (Fig 9).

Fig 9 Fitted Lock ring

Compress insert enough to fit protective sleeve; apply grease to top of insert shaft to aid insertion into thrust bearing. Place insert shaft into thrust bearing.
Rotate steering gear back and forth to work shaft into thrust bearing.
Place jack underneath wishbone ball joint and raise strut until shock absorber is compressed home, rotating steering gear as appropriate.
Raise jack until shock absorber is fully compressed.
Fit notched washer, lock tab and 22mm nut (or new nyloc). Washer may need rotating to allow fitment of C spanner. Tighten nut to 78 Nm, holding washer with C spanner. Bend lock tab into position.
Lower jack. Refit wheels, raise car to remove axle stands and lower to ground.

Note: Both torque settings mentioned above can be difficult to achieve depending on tools used – so achieve the best tight fit you can. The above procedure should not alter the suspension settings although it is recommended by Porsche to check settings after any suspension work. You may also find disconnecting the flexible brake hoses gives more movement for removal/fitting of the inserts, however, bleeding the brakes after re-connection will be required.


Job complete

The above work was carried out on my 1983 911 SC Coupe, December 2021