First to free the seat from the car one has to undo the side panels that are clipped on and also undo the screws followed by disconnecting the switches. Subsequently, pass the seat control unit from under the seat by utilizing tool 52 1 100 or any comparable and twist out the four bearing seats. It is necessary to drill out the rivets to take off the base plate and then the front seat height motor and the rails and finally the fore/aft motor. Pop off the backrest cover by unscrewing the two bolts on the side, if present, and lifting the cover over the top to unhinge it off the clips, and then unhook the wire connections if you have this feature. At the lower sides, operate the knobs in down direction to release backrest and then come out the headrest. Loosen the headrest gearbox cover, remove the bolts and get rid of the gearbox, also, get rid of the motor from the gearbox. Unscrew the bottom seat cushion, undo the bolts which are placed at the cable shaft retainer plate of the motor and pull out both the shafts. Take out the screws and the snapring at the backrest fittings and take off the motors. In installation, first in the motors, the Black is for the backrest position motor, the white one is for the seat up /down. Grease the splines for the backrest fittings and then fit the sleeve then the fittings and the snapring. Then fit the motor shaft and retainer plate, before fitting the seat cover. Next is the headrest motor and gear box, then the headrest shall be put in place. Screw the backrest on the seat bottom as well as join the wires noting the colors of the plug. Fit the backrest cover and screws and grease the splines , and fit the fore/aft motor the spring at the fore/aft motor and final tighten the mounting nuts. The height adjustment motor for the seat front should be installed, make sure the linkage is the same on both sides, the splines should be greased, and the sleeves put in. Last apply the base plate with new rivets or bolts, put the four bearing pins with tool 521100 or any other tool which is equivalent and do not damage the retainer or stops and then put the control unit and side panels.