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The ur-quattro propellor shaft is only available from Audi as a complete subassembly (part number 857 512 101D) including the centre universal joint and the carrier bearing. It is designed to last the life of the car, though as in many other instances our idea of life and Audi's idea of life may be different.
The carrier bearing is however available at a tiny fraction of the cost of a new prop shaft from BMW dealers under BMW part number 26 12 1 209 532.
It is also recommended that the constant velocity joint boots at the ends of the prop shaft be replaced - these are the same dimensions as Porsche 911 CV joint boots.
In the event the centre universal joint is damaged, it is available from GWB of Germany under part number 287000600000.
To remove the propshaft, first mark both ends so that they can be reassembled with the same orientation to the drive flanges. Tie up or prop the ends when undoing so that the prop shaft does not bend excessively. Place plastic bags over the ends and tie wrap them in place to prevent contamination.
Detach the centre carrier, noting carefully the position of any shims between the carrier and the body. These must be replaced exactly as found.
The centre nut holding the universal joint yoke to the section of propshaft carrying the carrier bearing can sometimes be undone using a ring (box) spanner with the shaft held carefully in a vice. Otherwise the universal joint will have to be dismantled by pressing out the needle bearing with an appropriately sized socket. It is advisable to keep each bearing's parts together for reassembly.
The carrier bearing is a light press fit on the front part of the propshaft. Derusting the propshaft and gentle drifting will remove it.
The grease nipple (zerk) on the universal joint should be pumped full of a standard LMP grease until clean grease emerges from each end of the "spider". This operation is often neglected during servicing, since it is only documented in the repair manual and not in the service worksheets. A parallel-sided grease gun tip must be used:
A spare propshaft grease nipple and the tip of gun required
This page was adapted with some new input and British English terminology from Chris Miller's original which should be consulted for any changes and for a more detailed description of disassembly of the universal joint.
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