Attention: When replacing the springs of one axle, always replace both springs. Be sure to install new BMW parts with the same numbers as those on the removed parts. For springs, the part number is on the end.
Withdrawal
Remove shock absorber.
In order to remove the shock absorber, you must first compress the coil spring. The coiled spring is compressed using a standard tool, eg HAZET 4900. Clamp the spring compressor in a vice as shown in the figure. HAZET plastic pads are used to protect the spring surfaces.
Attention: Never release the shock absorber mounting when the spring is not compressed.
Caution: Insert the grips of the spring compressor between the coils of the spring so that the coils are securely gripped and the grips cannot slip. The coiled spring is compressed with great force, so use only a serviceable tool. Never tie up the spring with wire. Danger of accident!
Note: Compress the coil spring only enough to relieve the thrust bearing. In no case do not compress the spring completely, its coils should not touch each other.
Loosen the retaining nut with a strongly bent ring spanner, while holding the shock absorber piston rod, depending on the version, either with an external hexagon wrench or an open ring spanner.
Attention: To loosen the nut, it is necessary to apply a significant torque; if necessary, loosen the nut with the help of hammer blows on the key. 1 - a torque wrench, 2 - a device for tightening the spring.
Remove puck.
Remove thrust bearing with O-ring and washer.
Remove the upper plate and spring lining, as well as the spring itself or remove the shock absorber from the spring.
Caution: If only the spring is to be replaced, slowly loosen the spring. If only the shock absorber is to be replaced, leave the spring compressed.
Remove the plastic elastic element, corrugated rubber boot and lower spring plate.
Installation
The new coiled spring is protected against corrosion by a pack. Before installation, check the integrity of the varnish coating and, if necessary, restore the coating.
Check bellows, plastic spring and lower spring seat for damage, replace damaged parts.
Insert the shock absorber with the lower spring plate, a plastic elastic element and a corrugated cover into a compressed coiled spring.
Complete the suspension strut according to drawings W-3B50 / W-3B51. When assembling, make sure that the coiled spring is in contact with the shoulders of the upper and lower plates.
Tighten the new self-locking nut a few turns.
Slowly loosen the coil spring until it rests on the discs. Ensure proper seating of the lower spring plate (rectangular notches).
Tighten the fastening nut to a torque of 65 Nm (with an internal hexagon on the piston rod: 45 Nm), while keeping the piston rod from turning. To achieve the prescribed tightening torque, BMW workshops use the HAZET 2593-22 interchangeable socket head and the HAZET 2927 holding tool.
Release the spring completely and remove the compression tool.
Install shock absorber.