5 replies to this topic

[eilz1999]

I have a 1980 mini 1000 with a single line metal master clutch cylinder. I am replacing the piston, GRK3007. See photo. Old one on the top. There seems to be a slight difference between the body and the lower rubber seal. Is this normal? Any help would be great. Thanks

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Edited by eilz1999, 19 September 2021 - 05:15 PM.

[croc7]

Based on the condition of the old piston, I would have a peek at the at the bore of the master cylinder. That said, the clutch master cylinder seals that I have replaced were a nice snug fit against the flange.

[eilz1999]

Thank for the reply. It would appear that this is deliberate. I have a diagram which points out that it is a narrower secondary seal. I've reassembled it and hope that I have no further issues.

[Ethel]

I've never noticed. If you're looking at the step on the piston it makes design sense as it would engage the seal, rather than on the lip when it returns to rest.

[sonscar]

I think that the end seal does the pushing and the second seal allows fluid to reach it and stops it leaking all over your carpets.It will probably be ok as long as it allows the return/feed hole to be open and covered at the right times.Its only the clutch so it may not be catastrophic if it fails.Steve..

[Spider]

There was 2 types of Clutch Masters that have the Tin Tanks fitted in production over the years. They are different internally, but off hand, I can't say if the 2 pistons shown here are from each of the types.