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harry33
PostPosted: Thu Apr 22, 2010 9:56 pm 
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Hi all,

I'm planning to do a 7.5" Cooper S disc brake conversion on my '76 Clubman. What changes to the hydraulic system should I make? I know I need to change the rear wheel cylinders, but I've read on other websites that the master cylinder and rear bias should be changed too.. What are people's opinions on this?

Cheers,
Harry
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drmini in aust
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PostPosted: Thu Apr 22, 2010 10:08 pm 
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On a `76 just change the rear wheel cylinders to 5/8" Cooper S ones, it'll be fine then. :wink:
The stock rear limiting valve is fine.

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harry33
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PostPosted: Thu Apr 22, 2010 10:18 pm 
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Awesome, that's what I was hoping for :)

Thanks,
Harry
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drmini in aust
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PostPosted: Thu Apr 22, 2010 10:38 pm 
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You will need to redrill the backplates for the cylinder dowels, S ones are in the other end of the cylinder.

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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. :mrgreen:
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GT mowog
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PostPosted: Fri Apr 23, 2010 7:26 am 
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This seems to be one of personal choice, but I'd also suggest fitting a booster.

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66S
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PostPosted: Fri Apr 23, 2010 9:02 am 
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Does anybody know what diameter the original Mk1 Cooper S rear cylinders were? There are no size references in the parts list but a few different numbers.

Regards
Al
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GT mowog
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PostPosted: Fri Apr 23, 2010 1:02 pm 
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66S wrote:
Does anybody know what diameter the original Mk1 Cooper S rear cylinders were? There are no size references in the parts list but a few different numbers.

Regards
Al


5/8"

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66S
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PostPosted: Fri Apr 23, 2010 1:19 pm 
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Thanks mate, I'll see what I have.

Al
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drmini in aust
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PostPosted: Fri Apr 23, 2010 2:02 pm 
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Yep the Cooper S and GT rears were all 5/8" out here, not sure about UK though.

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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. :mrgreen:
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66S
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PostPosted: Fri Apr 23, 2010 2:15 pm 
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Doc, under very hard braking, the tail of the car gets quite unstable and tends to wag !! I was thinking that there might be a little bit too much rear braking but any ideas? I've never really struck this before but the brakes are standard Cooper S and in ggo condition all round, factory Lockheed servo too.

Al
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GT mowog
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PostPosted: Fri Apr 23, 2010 2:46 pm 
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66S wrote:
.... under very hard braking, the tail of the car gets quite unstable and tends to wag !! I was thinking that there might be a little bit too much rear braking but any ideas? I've never really struck this before but the brakes are standard Cooper S and in ggo condition all round, factory Lockheed servo too.

Al


Sounds like the Pressure Limiting Valve in the Rear Subframe is either the wrong one or siezed. Even with the wrong rear wheel cylinders do they do this.

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