Brake question

On the brake master cylinder with the large (12mm) and small (10mm) union outlets (yellow band) can anyone tell me which should feed the
front brakes and which should feed the rears please?
Many thanks
Peter
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Whilst on the subject, is there a trick to removing the roll pin that holds the reservoir on to the body of the Master Cylinder please?
Mine seems pretty well rusted in. Need to get the top piston out to replace the seals.
Ideas appreciated.
Peter
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Easiest is to remove the whole booster assembly and knock out the roll pin with a roll pin punch. If it's an S you'll have to remove the air box and the shield behind the air box and the nuts on the inside of the vehicle or if it's a Cooper remove the battery and battery box and nuts.
Jay
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What battery box would that be then,,,, ?? Fitzy
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That'll be the one in the boot...
-Bob Rasmussen: all minis have the battery located in the boot, it is only the new BMW Binis that have the battery under the bonnet, except the S which does share the same quirk as the proper one.
RS
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The larger of the the two feeds the front brakes the smaller the back.
Jay
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Thanks all.
Yes. Sorry. I should have made it clear. This is a Mini Clubman Estate. 1979 V reg. As has been suggested, if this was about a new BINI, I would have posted on alt.autos.new-mini.
The battery is under the OS passenger seat.
I found a reference in Mini Spares web site wich confirms Bobs advice that the larger (top) feed goes to the front brakes and the smaller (bottom) feed goes to the rears. I anyone could confirm this that would be good.
The pin is a different matter.
It goes in from one side - and has to come out the same way it went in - because the plastic body of the reservoir gets in the way if you simply try to drive it through the same way it was put in.
So.
I'm now playing with a small G Clamp - to apply steady, yet increasing and, hopefully, unrelenting pressure - but I shall have to insert a packer piece - about 4mm thick - to support the plastic lug which bends as I apply the force through the G Clamp.
The plastic moves OK on the pin - but as yet, the pin is solid in the casting. Lots of WD40 last night. Fingers crossed but keep slipping off each other. Damned good stuff WD40...
Heat is not a good plan I fear as the plastic would shrivel and die.
If I had BINI I could take it into the BMW Emporium and let the man (or woman) fix it. But that wouldn't be restoration.
Thanks to all and any other ideas welcome
Peter
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Right. Pin is out. G Clamp worked a treat.
Battery is under the REAR OS passenger seat - not OS passenger seat. Doh!!!
Top union is 10mm. Bottom union is 12mm
Which one feeds front and which one feeds rears please?
P
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Hi pedro!
I had a quick check and assuming you have nothing too different then most cars run the rears on the primary circuit and the fronts on the secondary cirucit (top) You can normally feel this on a car if the rears need adjusting as the first part of the pedal travel gets stiffer! miniman
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Thanks miniman.
I stripped my CE down about 4 years ago and I've been 'restoring for fun' ever since. Now about to plumb the pipes and I have replaced the MC with a newer (yellow band) model.
Reading Kieth Calver's article on split brake systems and adjustable bias valves on the Mini Mania website he mentions that the top union is bigger than the bottom one. This isn't how mine is - its the other way round. 10mm at the top and 12mm at the bottom.
Interstingly, the Mini Spares web site has exacty the same article as Calver, under the name of bradley, with the same error re the unions. Not sure who copied who but it pays to check before posting someone elses work and passing it off as your own... :-)
Calver says as you do, that the top one feeds the fronts and the bottom one feeds the rears.
Given that Calver's article has the size of the unions the wrong way round (compared to the MC I have anyway) I felt I needed confirmation that his description of which union feeds which part of the circuit is correct.
You are talking to a man who almost plumbed an outside water tap to the hot system in error once... So I now try to measure twice, cut once...
After the false start in this thread with a kind chap telling me all about the BINI, I am grateful for your help.
Peter
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The main problem is that austin/morris/bl/rover/whoever over the years measured 17 thousand times and then did whatever the felt like at the time. It is possible that you and Calver are both correct. Sometimes, they picked whatever they had in the parts bin and turned it into a mini!
The Muffin Man

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mmmmm. hot water for washing the car, at least the outside tap would never freeze up in the winter! why has no one ever thought of that?!
And have you managed to get hold of a nice roll of kunifer to replace all your brake lines in?
It outlasts the standard replacement lines by lots, especially good if you drive on salted roads!
miniman
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Thanks again folks.
Yes I will be using the kunifer pipe thanks.
Can I just say I'm not doubting Kieth Calver. He has done quite a bit over the years and I am stumbling in the dark but there is a discrepancy and for this I need to be sure.
Just so I can get my head round this split sircuit braking malarky - I understand the idea. Two separate circuits in case something lets go. Better than relying on the hand brake at 70 mph :-)
Given that there are two distinct 'chambers' in the MC - one feeding the fronts and one feeding the rears - why does it matter which feeds which if you are starting again with a replumb?
Does one of the chambers produce a higher pressure than the other? Or is it that one chamber delivers the pressure slightly earlier than the other?
I'll do what everyone seems to suggest - top to the fronts - bottom to the rears - but I just wondered why?
I'm making up one of those adjustable bias valves for the rears and doing away with the regulator valve on the bulkhead.
And you wondered why I've been at this for nearly 5 years...
P
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