Is there any way to identify whether rear brake cylinders are 3/4", 5/8", etc. I have two new ones in a box but there are no parts numbers.

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-Alan
I blame my dad for my love of minis. I think I was conceived in the back seat of one
I also blame my Dad for me being 6' 1" - not really the optimum height for driving a Mini.

You're identifying the ones in the box and not on the car?

You can lift the rubber boot on either end of the cylinders and measure the diameter of the bore.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

Yup - in the box. I guess if they were intsalled on the car, I'd have to remove the brake pads first to do measure that.

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-Alan
I blame my dad for my love of minis. I think I was conceived in the back seat of one
I also blame my Dad for me being 6' 1" - not really the optimum height for driving a Mini.

I would suggest rather than looking at what has been fitted, look at what is correct for the car. 99% of the Mini's I see have the wrong rear wheel cylinders fitted.

Drums on the front - twin leading shoe = 3/4"

Discs = 5/8"

There were a couple of sizes for the rears when drums were on the front, but the 3/4" are about all you'll get now (for drum front end) and should work OK.

850s with single leading shoe front brakes had 5/8 cylinders on the back.
Twin leading shoe fronts had 3/4 rear
Discs had 5/8 rears, like Mr Mowog said.

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Have a Nice Day.
If already having a nice day please disregard.

I do actually know that but does anyone still run single leading shoe?

Considering how crap those old 850 front brakes were, you could probably fit BIG ones in the back and still not lock em up.

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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.

With the wheel cylinder in your hand, and the bleed nipple facing you and uppermost the 5/8 cylinders have the roll pin on the right hand side!!!!!
3/4 ones have it on the left hand side.
Obviosly back plates are different too but many have been redrilled.
Dave

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Now THAT is some useful info Thanks Dave!

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-Alan
I blame my dad for my love of minis. I think I was conceived in the back seat of one
I also blame my Dad for me being 6' 1" - not really the optimum height for driving a Mini.

i do and they are quite good as long as you have them adjusted correctly, have the "good" pads and never use them too much (just so they don't over heat)
drove the car to Brisbane like this, and probably will never change them for anything else. it is an 850 afterall

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