Bleeding Brake Nipple (4 pot)
 

Can anyone tell me the size of the brake nipple on a classic (year 2000)4 pot caliper.

7 mm is too small and 8 mm is too bit, it doesnt look worn or rounded and I don't want to try using a pair of vice grips as they would probably knacker it.

Thanks in advance

Should be 8mm from and 10mm rear I think. If you use a small set of vise grips and don't over do it you will be fine.