Required tools, replacement fasteners and order bushes.
This is a straightforward repair, there are very few components that need to be removed. Metric spanners, metric socket sets in ¼ and ½ drive, a suitable torque wrench and two brake pipe clamps cover the vast majority of the work. Consideration needs to be given to, supporting the space frame, the weight of the axle, how the replacement bushes will be fitted and, how the bush will be removed.
Supporting the space frame, I would usually lift on the rear jacking points and provide additional support by putting a stand under the rear axle. For this job the lifting and supporting positions are reversed so I prepared some wooden blocks to protect the aluminium jacking points:
I accept they look a little precarious but they fit in the cup of the stands and were absolutely solid.
Supporting and lowering the axle, Audi recommend a gearbox lift but I found a motor bike lift perfect for the job. It lowers the axle right down to the garage floor, lower than if I had used a trolley jack and pad
Bush insertion tooling, I used a universal puller / press set. All of the necessary sizes for bush removal and fitting are included in this set:
Bush removal, the above set will also remove the bushes when combined with a large bearing puller. However if the bush is particularly difficult access to a selection of drill bits, a power drill, large hack saw and possibly oxy acetylene would be useful.
Torque wrench, check that your wrench range is correct for the task. Rear axle fastener sizes and torque specifications (not applicable for 1.2 TDi):
Audi recommend that all bolts, screws and nuts applicable to this repair are renewed if removed. The stub axle nut has a RH thread on both axles; it is safety critical that these nuts are renewed if removed.
Order new fasteners or reuse? The Audi manual states that all bolts, screws and nuts, relating to this job, are use once only. It is a good idea to order and collect replacement fasteners before starting work to avoid any risk of work being delayed parts on backorder. However if you are delayed by a fastener backorder or unsure of the need to to replace all fasteners then a summary of an A2OC group discussion on this subject follows:
It is important to replace all self-locking nuts, however some A2OC members suggest that the bolts are not Torque to Yield bolts, more commonly known as stretch bolts, and are therefore safe to reuse. Stretch bolts must not be reused, all bolts stretch but a stretch bolt is stretched beyond the elastic zone into the plastic zone.
The advantage provided is that the stress strain curve is much flatter in the plastic region so the clamping force is better controlled. The clamping force is set by a characteristic that is manufactured into the bolt; it is not variable depending on the friction felt by a torque wrench. The friction felt by a torque wrench is dependent on the condition and lubrication of the threads and so can be quite variable. Finally a stretch bolt provides a greater clamping force for a given bolt size. Stretch bolts when removed cannot return to their original length and strength and therefore must not be reused. If you have any doubts replace your fasteners as advised in the manual. For others I summarise a debate regarding stretch bolts here on A2OC.
A standard bolt stretched within the elastic zone generally has a single torque figure specified, ie 55Nm. The torque wrench can only respond to friction felt which in turn will be influenced by cleanliness of the threads, lubrication etc. The actual amount of bolt stretch achieved therefore can be variable along with the associated clamping force.
If tighter tolerances are required for the clamping force required from a standard bolt stretched within the elastic region then a lower initial torque followed by an amount of turn can be specified, ie 30 Nm + 90 degrees. A portion of the stretch is determined accurately by an angle of turn after a possibly less accurate torque wrench setting. As the stretch is tighter controlled overall then so too is the clamping force. A torque wrench setting followed by an angle of turn does not necessarily confirm a bolt is a stretch bolt. A screw is unlikely to be a stretch fastener because there is no thread free portion where necking can occur.
A torque wrench only setting cannot be specified for a stretch bolt. A torque wrench that takes a bolt to the point of necking will never click. It will continue stretching the bolt to the point of failure. Torque specifications for stretch bolts specify and initial clamping force followed by an angle of turn. A stretch bolt can generally be identified by a slightly reduced diameter unthreaded portion of its length between the head and the thread. This is a head bolt set supplied by Elring:
In the future I will be making a judgment based on this information and only replacing bolts that are likely to be stretch bolts.
Order replacement bushes
I no longer use Audi for parts such as this. I find Febi Bilstein offer a very good quality product at a lesser price. Their Parts Finder site allows you to set up an account, save your vehicles and then search for parts. The site does not take orders so you can then Google the part number for the best price:
Please visit the site and input the details of your A2 to ensure that you order the correct bush.
