don't wait till you see what they're like, because the day you need to have smaller rear wheel cylinders is the day you end up going backwards instead of stopping..... take my word for it, change the rear cylinders now....

Minimad has the most bling brakes on this forum..... he wins hands down

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did I tell you that I won a trophy?

The ratio of the piston areas will determine if the rear cylinders need changing or not. To assume this is the same as std cooper s is not the correct way, I'm sure the new front calipers have bigger pistons.

In any case, when you take it to get engineered thats one test that they'll do, see if it locks front before rear.

Daniel

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Videos - Turbocharged A-Series on Dyno & at Wakefield
Mafs waz not my strong subgeckt at skkol

Well others have had success with S rear cylinders.... So thats wat ill fit. Im gunna order some and get them airbagged up here ASAP... Cause no 1 north of Brisbane has em.....

But its not like there is much in the way of choice for rear wheel cylinders, its either 5/8 or 3/4.....

Im not taking it to an engineer....

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http://www.youtube.com/user/Hanras

i wouldn't worry about your studs shearing either as they don't really take much of the load it is the clamping force on the face of the wheel to the disc to the hub that transfers the torque. thats why stud only shear when the wheel nuts are under torqued

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FOR SALE MInidlx, 1293, GR head, RE-13, GR worked Redline Manifold, 45 mm DCOE,pulsar dizzy , "S" Disc's, Mk II "S" box, 3.65 diff. Minator 10X6's On the loose

Yes the piston is bigger than S, but there's only 1 of em... not 2.
Not just to do with piston area though, the disc rotor diameter and hence the pad clamp radius come into it.
Trust me, a 9.1" Honda brake kills a 7.5" S one for retardation.

It's the weight tranfer rear to front that is the problem. Rear brake line pressure on an Oz roundnose Mini is limited to 375psi or so, it's not a proportional valve like a Wilwood etc.

ps. I had to do Barney's rears (replace em with 5/8" S ones) when I had Hondas on front, and they were turned down from 9.1" to 7.9" and the pads trimmed too.

Better safe than sorry. If rears lock up at speed in an emergency, you are then a passenger.

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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.

Yeah i still havnt driven it yet..... Need to bed the pads in but worried bout ending up sideways down the highway while i do some high speed heavy stops from 80 kph down to 20kph.....

Ill order some S cylinders 2morrow...

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http://www.youtube.com/user/Hanras

For reasons best known to Mr Issigonis and BMC, the dowel pins on S rear wheel cylinders are offset exactly opposite to the standard ones. So, you will have a pair of dowel holes to drill in the backplates in situ, carefully.
Don't be tempted to run without the dowels.. the cylinders will move around.

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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 for that Kev.... Not the news i wanted to hear.... But now im prepared for it..... BUGGER..... Im meant to have the car ready for a cruise this coming Fri..... Hmmmm...... Spewin

Kev, are the S cylinders still fixed to the backing plate with a big circlip....?

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http://www.youtube.com/user/Hanras

Yes, same setup, except the dowel pin is in an opposite spot.

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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.

Issigonis: Hey, Mr Lockheed, can I have a smaller diameter one of these?

Mr Lockheed: Sure, we've got these ones, the dowel is in a different spot to the ones you already have, cos someone else wanted them with the dowel over there.... if you want to move the dowel it'll be a heap extra dosh cos we'll have to remake patterns and junk,and it'll confuse the monkeys that we get to make them

Issigonis: nah, bugger that... I'll just drill the hole in the different spot

Mr Lockheed: no wuckas, when do you want 'em ?

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did I tell you that I won a trophy?

I had a few types of rear brake backing plate in my collection when buiding up Mokesta. I didn't look closely enough to notice the difference.

Not only were some of the dowel holes on opposite sides (so you don't fit the wrong ones I guess) but the plates were pressed to a different depth. One set of plates suited the 1.25" wide brake shoes and the others fitted 1.5" wide shoes. Confused the crap out of me at the time when trying to assemble the bits.

Oh, and go for the small cylinders. I didn't initially and ended up slewing past some granny who pulled out of a side street in front of me. The car was going straight past her but pointing towards her. Old girl looked as shocked as I felt. Mokesta has one of those Moke limiting valves with the ball and ramp inside. I'd love to be able to adjust it a bit. It still locks up rear first...

Some back plates have holes for BOTH dowells. The 72 Clubman van that donated many bits to my Moke had them. I have another pair like that too. Neither appears to have been drilled later.

Regarding the ball type limiter valve, you can adjust them by altering the angle of the valve. Vizard details this in "How to Modify Your Mini".

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Brett Nicholson
Greendale (near Ballan) VIC.
1971 Morris Mini Moke
1966 Austin Mini
1965 Morris Mini Traveller
1973 LR Series 3 88
2007 LR Freelander 2

So ive fitted 5/8in rear wheel cylinders this arv, found a place locally that stocked em.... UNBELIEVABLE!!!

The brake backing plates that im using have BOTH the dowel holes already there!!!! So i didnt have to drill new holes.....for once something was easy....

So just gotta bleed em 2morrow, wait for some fine weather n do some high speed stops to bed the pads/rotors in. Ant try not to do front flips down the highway.....

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http://www.youtube.com/user/Hanras

What ? Like this ? The finish at Rob Roy Hillclimb.
Full Cooper S setup, but cold competition pads that don't offer enough bite.

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Curly
'64 Cooper 'S' (Group Nb spec)
'67 Mini Marcos GT www.mm7056.wordpress.com

And the A032Rs go owwwwwwww