The UK quattro Network
The UK's mobile Audi 5-cylinder mechanic - 07833 654800, 24x7
Specialist in turbos, quattros, electrics and non-starts.

Replacing the shock absorbers and/or road springs on an Audi ur-quattro

Parts required - per wheel:

• 857 413 031A Shock absorber (or after-market equivalent)
• 431 412 047B Retaining cap (often shipped with above)
• N 022 150 1 Self-locking nut (often shipped with above)
• 811 412 365 Slotted nut (always replace - correct torque cannot be achieved with a damaged nut)
• 857 412 323B Strut top mount
• 857 412 131 Bump stop
• 431 412 135 Gaiter

A variety of different road springs are available both from Audi (for cars with or without air conditioning) and from after-market suppliers

In this (recommended) procedure the strut remains on the vehicle - brake caliper, pad warning and ABS connections are undisturbed. Neither the anti-roll bar nor the wishbone bushes are demounted.

Tools:

• Tube socket for shock absorber cap, e.g. Hazet 2593-33. This is an external drive 33mm socket almost 30cm in length and weighing 1.8kg.
• Spring compressors, preferably turnbuckle type or with a captive rear end.
  
  The conventional type (above) may be difficult to use within the confines of an ur-quattro strut tower and may gouge, leaving a corrosion site. The turnbuckle type (below) has both left and right-hand threads and so does not still protrude into the strut tower when the spring is compressed.
• 22mm cutaway socket, e.g. Stahlwille 1051.
• 7mm long-handled Allen key (some aftermarket shock absorbers use 6mm).
• 22mm socket insert to drive slotted nut - available from most motor factors as a set of three.
• Trolley jack - small will suffice.
• Torque wrench to cover 60Nm to 180Nm.

Procedure:

• Loosen the road wheel nuts
• Jack the car and place an axle stand under the subframe mounting bolt.
• Remove the road wheel.
• Using the cutaway socket and holding the strut with the Allen key, remove the self-locking nut over the dished strut retainer.
• Apply the spring compressors over at least four turns of the road spring and tighten until the spring moves freely.
• Using the 22mm insert, cutaway socket and Allen key, remove the slotted nut.
• Tighten the spring compressors.
• Using the long end of the Allen key, press down on the old shock absorber until it is retracted. Quickly remove the strut top mount.
• Repeat the above procedure for the upper spring seat, bump stop and gaiter.
• Slide the tube socket down over the shock absorber until it locks into the retaining cap.
• Unscrew the retaining cap - removal torque may be considerable.
• Depress the shock absorber again using the Allen key and remove the retaining cap.
• Remove the old shock absorber by retracting it upwards through the top of the strut tower.
• If changing the road spring, remove it now, take off the spring compressors, compress the new spring and insert it.
• Read the installation instructions for the new shock absorbers carefully.
• Slide the new shock absorber down into the strut.
• Using the Allen key to depress the new shock absorber, slide in the new retaining cap and screw it loosely into place.
• Slide the tube socket down over the shock absorber until it locks into the retaining cap.
• Torque down the new retaining cap - note that the specified torque is considerable and very hard to achieve without the socket.
• Reverse the gaiter, bump stop, spring top seat and strut top mount removal procedure.
• Using the 22mm insert, cutaway socket and Allen key, torque up the new slotted nut.
• Place the road spring correctly against the upper and lower spring seats and release the spring compressors.
• Replace the dished strut retainer and torque the new locking nut to specification.

It may be useful on occasions to compress the strut using the trolley jack in order to fit or remove the spring compressors.

Kerbside Motors Home Page