Remove the retaining spring 1 (see photo), fork 2 and clutch release bearing 3.
Check the bearing height, i.e. size "B" and "C" (see photo), the values of which are indicated in the subsection "Detailed technical characteristics".
When installing, apply long-life grease such as Molykote BR2-750 to the inner groove "N" (see photo) of the bearing. Lightly lubricate the guide bushings and supports with long-life grease such as DC 44. Without lubrication, the clutch release bearing may seize on the guide bushing.
(Examine the original source using the link on the website «BMWMan.ru»)