Disc brakes on a standard Mk1

[miniminor]

Not saying I'm going to but idly considering upgrading my original single leading shoe front brakes to discs.

What is the easiest and most effective set up to put onto a standard mini, Cooper 7" discs, Cooper S 7.5" discs? Would need different outer cv joints for the S set up.
Is a servo totally necessary? I had a '87 mini with 8.4" discs and no servo and it was completely fine.

Thanks

[Polarsilver]

What about Twin Leading Shoe Brakes .. set up correctly they do the job

[Peter Laidler]

On the other hand and probably cheaper, what about a set of standard Cooper 7". Same drive shafts, trouble free and seemingly plentiful 2nd hand as Cooper owners seem keen to swop for S set-up. Wheel base/track and wheels remains the same. If you ain't got a servo presently, why bother. It doesn't make the brakes any better or more efficient. And better still, pretty well unnoticeable to the concourse stasi

[gs.davies]

I’ve got the 7” set up on my car.

Absolutely trouble free, no endless messing about with adjusting them up, no farting to one side or the other.

Wouldn’t want to blast round a track for ever on them but for road use, they’re perfect.

As others have mentioned, will also keep the track width and appearance of the 850, no drive shaft changes, just swap the hubs over, fit the drive flange, disc and calipers, job done.

['S'-type]

Easiest way is to buy a complete conversion kit from the usual suppliers (about £500).

Cheapest is to swap over a complete second hand 8.4 set up including drive shafts which should fit straight into rubber yoke set up. But you don't want 12" wheels.

Compromise - as above but also buy a 8.4 to 7.5 conversion kit about £200. includes flanges, discs , calipers and pads. Calipers will be pattern.
Or if you want more expensive calipers buy the parts separately and calipers of choice. 'Genuine calipers are expensive, Minispares branded are fine.

I would say you can do without a servo, just need more leg power.

Driving in modern traffic with SLS brakes is no fun. Mind you it wasn't even in the 70s when I managed to rear end someone who had suddenly emergency braked for no apparent reason.

PS with ET 31 wheels no need for arches.

[SMOKE GREY]

Plus 1 for the 7” cooper brakes, especially a road car.

[miniminor]

Driving in modern traffic with SLS brakes is no fun. Mind you it wasn't even in the 70s when I managed to rear end someone who had suddenly emergency braked for no apparent reason.

PS with ET 31 wheels no need for arches.

No it does need a good safety margin for stopping!
Won't be putting arches on it, keen to retain the standard looks, steel wheels with wheel trims. Guess the 7" Cooper set up would be the way to go.

[SMOKE GREY]

Driving in modern traffic with SLS brakes is no fun. Mind you it wasn't even in the 70s when I managed to rear end someone who had suddenly emergency braked for no apparent reason.

PS with ET 31 wheels no need for arches.

No it does need a good safety margin for stopping!
Won't be putting arches on it, keen to retain the standard looks, steel wheels with wheel trims. Guess the 7" Cooper set up would be the way to go.

Think I have some NOS callipers in the loft. Would need to check to check though.

[jamiestevens94]

I'm currently running drum brakes on my mk1 which are fine but I have been looking to upgrade to the 7" cooper set up to save on changing the shafts etc and to save on costs. I've found it difficult to find the parts I need to date though.

[Peter Laidler]

What parts exactly Jamie. As mentioned to me at Beaulieu last year is that those who have removed the 7 inch Coopers are willing to sell but only as a whole set.

And don't forget that because the 7" and 7.5" hubs are the same you can use S taper rollers too.

Drive flanges are not a problem now - as shown by a couple of mechanical maestros on this very forum

[jamiestevens94]

I can't seem to find any sets or individual parts on ebay, forums or facebook groups. So I am guessing it might be a case of who you know? Or I haven't seen any for sale since looking for them. Only thing I can find is the new pads and discs from suppliers.

If anyone has sets available, feel free to send me a PM. (sorry to jump on this post). Thanks

['S'-type]

If by any chance anyone PM'd me recently apologies if I don't reply. I think I got a notification but my inbox was full. When cleared it nothing new showed up. Is that how it works?
Sorry about the IT incompetence.

[miniminor]

Checked all the usual suppliers it seems to be only 'S' 7.5" disc conversion kits available.

[Peter Laidler]

I think that you'll find what you want on this forum within a week or so.........

[timmy201]

My limited experience is below:
Twin cylinder drums - excellent on the road if properly adjusted (for a low power car). Parts are easy to get, performance is decent and I never experienced any fade even down long mountain passes. Sure they aren't suitable for a track day, but neither was the rest of my mini

7.5" unboosted - similar pedal feel to the drums. I think it must have been my poor pad choice (green stuff) but mine are a bit dull when cold, and I don't tend to push the brakes hard on the road
7/5" boosted - similar to a new car, less effort and easy to modulate.

Changing to 7.5" takes a lot more work and money than simply the kit they sell however. Add on rear wide drums, studs, potentially new set of wheels etc. Then there's all the other things it makes sense to do at the same time like new rear shoes, wheel cylinders (especially if you have the wrong size for discs) and brake hoses

Standard 850 steel wheels fit fine with my 7.5" brakes and didn't stick out of the arches, so you should be able to keep them. Some can apparently be tight in clearance to the caliper but mine were ok
If you compare:
Minispares 4.5 x 10” ET 32
Standard steel 3.5 x 10” ET 24
The std steels will stick out 5mm less

[Chapmag]

Following, G

[Spider]

Checked all the usual suppliers it seems to be only 'S' 7.5" disc conversion kits available.

That's what I'd suggest running with as all parts are still readily available new. Fitting the 7.0" Cooper Brakes could become problematic down the track when looking for drive flanges or calipers.

As well as changing out the front brakes, don't forget the rear wheel cylinders need to be changed too, 5/8" here would be a safe size.

[W1NG3D]

Fitting a set of 7.5" S discs was the first mechanical upgrade I ever made to my Mk1, they're great to use, and spares are readily available along with upgrades. I haven't got a servo, and still use the old standard master cylinder with a plastic extension. I got mine from Minisport if I remember rightly, but all of the main sellers' "conversion kits" are probably more-or-less identical.

[mab01uk]

If you regularly drive the your Mk1 on modern roads I would also advise go with 7.5" discs (with or without a servo) and keep your old single leading drum set-up in a box to give to any future owner who wants to experience some extra excitement in modern traffic conditions and does not mind risking their no claim bonus in the process....

[Polarsilver]

often overlooked the rear subframe mounted brake regulator .. get the correct one to suit the brake setup ..however you control the rear brake bias never ever have a situation where the rear brakes lockup .