Apart from the position of the tank to the cylinder is there any differance between the brake and the clutch master cylinders, as in the volume each pumps ?
I wouldn't have thought so as both seem to have the same bore but i want to make sure.

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76 1275 Leyland S

Clutch master cylinders are all 0.750" bore (or should be...)

Brake masters varied- original 850 was 0.750", late 998 Cooper was 0.625", all others were 0.700". Many Clubbies had tandem (dual circuit) ones.

Brake masters all have a restrictor valve in the top, clutch ones do not.

<edit> brake MC sizes above do not apply to late UK imports- I know f'all about them.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

In the master cylinders with the metal body plastic tank both the bore sizes are the same, they are exactly the same unit except that the brake master cylinder has a non return valve and the clutch one doesnt. Not to sure about the tin tank master cylinders though?

The new plastic tank type replacement brake cylinders are 0.700" bore.
p/no is GMC171.
Clutch one with plastic tank is 0.750" bore, p/no is GMC1008.
They are not the same but do look it...

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Extract from Gregorys Workshop Manual Pg 131 states, The brake and clutch master cylinders are identical, except that the clutch master cylinder has no non-return valve. Who is right??

They were right back when the 850 was all you could buy....

But, since 1965, (when twin leading shoe front brakes were fitted) all Oz Minis have had a 0.700 bore master cylinder, not 0.750.
This includes Deluxe, Cooper S, Mini K, etc.
late Clubbie brake MCs were tandem, but still 0.700" bore.

Source- Leyland Australia's factory MINI workshop manual (the last one produced here, 1976- still available from Pitstop Bookshop)

My part numbers for the NEW cylinders are from Karcraft's current catalog.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Thanks guys.
I think all that info has helped ?

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76 1275 Leyland S