Which is the primary circuit - the top pair of pistons (one bleed screw) or the bottom pair (two bleed screws)?

I don't think there is a primary and secondary. The pistons are the same size and they were simply coupled as two halves of the dual circuit system.

Metro 4 pots and vented discs weigh a massive amount.
You would probably be better off with aftermarket alloy 4 pots and standard discs?
It's not as if the GTM is a big heavy road car.

Ta!

I know they're (very) heavy but I've got them so they'll do for now until I get it on the road

I changed my brakes last year to some huge 10 inch vented discs and 4 pot ally calipers, and saved weight on my std 8.4 setup almost 1kg per side, and im sure i could feel the difference when i first drove, in a good way with the reduced unsprung weight,

Std 8.4 are not bad on a GTM ran them for ages on mine, only reason to change to my new setup, were to increase brake feel with the increased size disc and to give more fade resistance for trackdays etc. plus to loose a little weight.

WEST

Do'nt forget some earlier Metros had 4 pot calipers and 8.4" solid discs

.......and it's a dead easy swap too. All you do is change the calipers using the ERA bolts (from Minispares) and couple up the hydraulics using one of the various conversion kits available. You can even use the original Mini dust shields if you trim a little metal away and bend the brackets slightly. For road use there is very little to choose between the solid discs and the vented.

So how do the metro calipers work with the 8.4" solid discs… are they not too narrow compared with the normal metro vented items?

And what drive flanges would you need to use?

J

Some Metros had 4 pots with solid discs, that's what you need to look for, these are a straight swap with the Mini 2 pot jobbies apart from the caliper bolts and hoses, read Johns post above Everything else remains Mini ie drive flanges etc

These are what to look for http://cgi.ebay.co.uk/PAIR-OF-METRO-FOU ... .m14.l1262

Oh, I see. I thought you meant that the normal 4-pot calipers used with vented discs could be fitted to standard mini discs.

Cheers

J

The calipers are almost the same but with a slightly wider slot where the disc goes. The first of the ones for vented discs actually just had a spacer put in between the two halfs of the caliper but later the spacer was incorporated into the casting.

Iain