There are several different manufacturers who have supplied the steering pumps for BMW XS vehichles and as far as removal and installation is concerned, most of the models are very much alike. First, you must expel the power steering fluid from the reserving rinsing it with a clean syringe, to make sure that the previously used fluid is not put back. Lift the front of the car and take off the under engine splash guard. Then, detach the accessory belt from power steering pump with a pointer to its rotation if the belt will be reinstalled, and, if necessary, unbolt the alternator cooling duct. On the power steering pump for the 6-cylinder engine, site the vehicle to remove the fluid hoses, maybe, require a bucket to hold the dripping fluid. Sic the fluid supply hose clamp, remove the pressure fitting and plug the openings in the pump and hose ends to minimize on contamination. Unscrew the bolts used to mount the pump and pull the engine down to take out the pump with the pistons when possible and it is advisable to also note the spacers or shims that maybe present. Installation is done in the reverse order of the removal; the pressure fitting seal and the hose clamp on the fluid lines are fitted back into position. Same goes with M62 TU VS engine power steering pump which could be of LUK or ZF brand: remove the fluid hoses in same manner but mind to seal the holes if any. Take off the front mounting bolts on the right side, the bolt of the fluid line support bracket, and the rear mounting nut. Be sure all thread bores, bolts, nuts, fluid couplings, and mating surfaces are clean and dry; also, clean the inside of the accessory belt where it contacts the mating surface of the joiner. Replace the sealing rings whenever you reconnect the pressure lines of the power steering; make certain that the hoses are sufficiently far away from the suspension; fasten the fasteners of the front pump and hand tighten the rear support nut of the knurled type; then install and tighten the rear mounting nut but do not over-tighten the banjo bolts. For the N62 V8 engine power steering pump, as with the A8 4.5L, remove the fluid hoses by severing the fluid supply hose clamp and then using the pressure fitting to stop the flow while removing the two pressure fittings from the supply and return hoses. If required, loosen and unbolt the pressure line bracket and the pump mounting nuts, as well as the top mounting nut or bolt. Remove the pump from the engine compartment and for its installation reverse the above process, while making sure the hoses are free from the chassis and have enough room to move around. Last but not the least, call up the power steering system with the specified fluid which also makes the system to bleed.