Master Cylinder: Disassembly
WARNING: This page is about a different car, the 1994 BMW 525iT. However, it is still accessible from the selected car via links, so may be relevant.
Push in primary piston and remove plug. See Fig 1 . Remove retaining ring from end of cylinder. Remove primary and secondary piston assemblies and stopper washer. Disassemble piston assemblies, noting number and position of parts used for reassembly reference. See Fig 1 .
NOTE:
Replace master cylinder if cylinder bore is scored.