Simplify the refurbishment of the master cylinder, with new, correct specification parts that, when fitted correctly, will bring the brakes back to showroom fresh effectiveness!
For other master cylinder components that may need renewing, check the schematic for your model, and see all the parts clearly with the 'Big Image' facility, where they fit and, importantly, the correct part numbers!
Other parts you may wish to consider:
920091570
920151233
920331186
920371827
920550741
92075161
921501328
921511219
921520017
921701090
921710376
430950067
430950105
490161147
920021323
921530628
921701091
TIP: Fill the reservoir with brake fluid and leave for a few hours before bleeding. You will be surprised what gravity can achieve! Make sure you order all the parts you require at the same time and save money by avoiding multiple shipping charges.