Classic Mini Rear Disk Brake Conversion


Well as i have something at the front of my car to look at (16v) I thought I should have something at the back for people to look at. So i though how about REAR disc brakes. I know the don’t give a performance gain, they add to the unsprung weight (whatever that is) but the door look bloody good !First problem i got is to find a calliper which will fit and work properly. There where ideas that i should use a 4-pot calliper of a metro, but i am still not sure if hydraulic handbrakes are legal ? even if they are i might have problems with uneven pad wear. What i needed was a calliper that works by cable and hydraulic. The one i have found is off a Ford, they come on the 4×4 Sierra’s and grandadas etc.. these are a single piston type which helps fit under a mini wheel. I have to say at this point i am fitting 13 inch wheels so do not have the stress of trying to squeeze them under 10 inch wheels… although i am trying to fit them under 12 inch wheels.

The disc i am using is off a Ford Fiesta Mk1/2 which has a diameter of 220mm. The pads for the above calliper fit on this with a few millermitres to spare.

So how is it all going to fit… well the idea is : (have all the bits will be fitting over the next couple of weeks) to re drill the disc to fit over the rear hub stubs e.g. mini stud pattern. I need to make up a locating ring to make sure that the disc is in the centre of the hub as well… but that is not to hard.

The next stage is to mount the calliper.. for cable reasons i am mounting the calliper under the radius arm so that the hand brake cable will run in its old position. I am going to make a plate that bolts onto the two bottom back plate mount holes and then that hold the calliper.

Well hopefully i will have pictures to follow soon so keep checking here !

User Contributed Notes: Rear Disc Brake Conversion
david.doherty4@ntlworld.com
08-September-2000 00:00
Hydrolic handbrakes are illigal
Ford rear calipers suffer from seizing because their position. poss more so if you mount them below the arm. you also need a special tool to replace the pads.
Alfa use some alloy calipers on the front of some of their cars. The handbrake operates on the front wheels.
Later 2CVs are fitted with fairly small calipers with are quite light.
Good luck Dave
markc57@hotmail.com
28-September-2000 00:00
my note's about the rear brake conversion , I was bleeding some brakes on a trans-am the other day and I noticed the rear caliper's connected to a normal type handbrake cable , they were vented as well , a bit overkill i know but you could always turn them down a bit , just another thought the wouldn't be that hard to get hold of either .
david.doherty4@ntlworld.com
14-October-2000 00:00
Another thought you will be unable to bleed the calipers unless you take them off and turn them round, the bleed nipple has to be at the top to allow the air to escape.
I think that with the breaking effort applied to the disc below the hub, as you brake, it will try to lift the rear up! Normally a sierra squats down at the rear when you brake.
I really do think that you need to reavaluate this plan.
Dave
David.doherty4@ntlworld.com
14-October-2000 00:00
When I have used these calipers before, on my Escort rally cars we have had to run 14 inch wheels to clear the calipers.

Dave

matthewgreen@1gladstone.freeserve.co.uk
16-October-2000 00:00
Thats ok Dave... more thoughts the better.
I was worried about mounting the calipers underneith .. that bit i will just have to suck and see.
On the bleeding side.. will have flexi hose to them so worst case can take them off to bleed ... as you don't bleed them very much i can't see much of a problem. The other thing i thought of was to swap the bleed nipple to the other hole ? what do you think ?
And fitting under your escort wheels... i bet you discs where allot bigger.. my discs are 8.45 inchs.
david.doherty4@ntlworld.com
16-October-2000 00:00
Matt I hope you don't think that I am just knocking your work/plans. I know what its like to spend time/money on work and then find out that it doesn't work.
Good luck Dave
David.doherty4@ntlworld.com
17-October-2000 00:00
Unsprung weight means the weight that is not acting on the supension when the car is standing, ie:- brake,drums,discs,calipers,wheels
Dave.
david.doherty4@ntlworld.com
17-October-2000 00:00
By the other whole do you mean where the brake pipe fits? If so I doubt it will fit, remember the bleed nipple seals into a funnel, for want of a better word, Memeory tells me the hose has a sealing washer?
We used XR2/3/sierra discs with 13inch wheels and XR2 calipers (illugal for road use, no handbrake, and cossy discs with 14inch.
I still feel that those rear calipers are too big for the rest of the system, at the very least you will have to fit a adjustable valve in the rear brake line, there is a description how to modify an early Mini one on a web ring site, can't remember which one!
Talk soon Dave
blackmin@hotmail.com
17-January-2001 00:00
Hi am also looking at putting discs on the back of a mini... I have found that early model Magna (australian) callipers look about right, all alloy, single spot floating.. handbrake cable fixture etc... only problem i am having is trying to gain enough clearance so that the wheel will be able to travel upwards inside the rear wheel arch... am looking at a large offset out towards the rim...

Dave good point about the breaking forces pushing the wheel up i hadn’t thought about that, i was planning to mount them vertically at the rear… ie max leverage… am not 100% sure about the reasoning and actual effect of it though… but sounds reasonable…

blackmin@hotmail.com
23-January-2001 00:00
Hi again.. the magna calliper was no good... but went back to wreckers and found a R31 skyline/pintara calliper which looks the goods... designed a bracket up to be made out of 6mm steel, and am still searching for a disc rotor that has a 39mm offset hat, to hide my spacers that are needed to keep the wheel from hitting the trailing arm...

Seems to be a goer, will be using the handbrake cable from the car, although will be running sort of where mini one does.. ie under the trailing arm, but as it has an inner and outer, it doesn’t need to run through the subframe etc… giving much better leverage and efficiency 🙂

phil@erinues.dyndns.org
22-February-2001 00:00
It doesn't matter where the caliper is mounted (top, bottom etc.), as the force is in the same direction whatever. i.e. it is a rotational force that it is producing in the opposite direction to the wheel rotation.
Blackmin@hotmail.com
27-February-2001 00:00
Phil yeah that is the conclusion i came to aswell... hence caliper still on the rear most section...
minimonster@zonnet.nl
14-March-2001 00:00
If you don't want 2 use a coil over conversion for the rear springs, it does matter where the caliper is mounted!
matt@16vmini.co.uk
25-March-2001 00:00
I did phone them when i was thinking about rear discs... theres is not road legal yet.. although they did say they where designing a pair for raod use... I guess they are not going to be cheap as the don't do cheap stuff 🙂
Djdave@freenet .co.uk
25-March-2001 00:00
Hello, what about the KAD conversion, have seen it in the mini mags, haw and where do they mount theirs and what paarts do they use... I know its sort of cheating but it's got to be worth a look eh?
matt@16vmini.co.uk
26-March-2001 00:00
They do good stuff, i have heard nothing bad about them. What do you mena the qucik shift is not road legal ? first i heard.
Djdave@freenet.co.uk
26-March-2001 00:00
Hi matt, Yep I know what you mean about KAD stuff being expensive!... I brought a quickshift some years back, but the quality seems quite good :)Did'nt realise that they are not road legal... Oh well that's that out the window eh? BTW...Great site... really good!
djdave@freenet.co.uk
27-March-2001 00:00
Hi Matt,
Sorry... I was talking with regard to the rear brakes... not the quickshift!
When do you hope to have your car ready and on the road?
pc_willow@hotmail.com
02-April-2001 00:00
What brake bias are you planning to use? I am currently restoring a mini van, that will run a metro turbo engine and rear discs.
chip@uksite.co.uk
25-April-2001 00:00
A brake bias valve is readily available from any mini shop, normally about 30-40 quid or so.

Chip

smitty354729778@aol.co.uk
29-May-2001 00:00
Good luck and the rest, isnt there a kit due to be released by 'KAD'? i know it wont be cheap! So i hope it works for you, have yo looked at the 205 1.9 Gti rear brakes?? the disks could be turned down, probably a long shot

Matt.

Pat_j_griffiths@hotmail.com
14-July-2001 00:00
Are Hydraulic handbrakes legal?
Cos if they are another way of rear discs is to use a disc brake front end, chop of the towers etc and fabricate new mountings to match the existing mountings in the floor.
I've got a front subframe under the back of my mini, although 've cut out the boot floor and rear seat so I can mid mount the engine.
Pat
prwilkinson@netscape.net
09-August-2001 00:00
I have had a chromoly beam rear-end fabricated for my Mini deJoux GT. I am currently thinking about a rear-disc conversion (must be road legal ie. mechanical handbrake) My problem is that I am using 10' wheels. I was thinking about using standard Mini discs, flange etc and trying to find a modern caliper that has a low enoughprofile and can handle the 7.5' diameter without pad overhang.
My questions are: is a disc set-up going to weigh less than Mini drums with minifins and does anyone know of any calipers which may be suitable for my application.
If a disc set-up weighs more then I will bin the whole idea as I am trying to reduce unsprung weight. If the handbrake wasn't an issue I'd use motorcycle brakes!
Cheers for any thoughts.
Paul
maxsini@optusnet.com.au
01-September-2001 00:00
re where to mount calipers: - i am no expert in chasis design but surely it does not matter about the location of the caliper relative to the suspension arm mounting. what does affect the way the suspension (and car) behaves when you brake is the type and geometry of rear suspension - currently you ( and me) are stuck with trailing arm suspension - unless of course you want to play around with double wishbone suspension or motorbike type suspension and have pivoted calipers that use levers so that braking reaction forces act against brake dive
max
peterbenn@tinyworld.co.uk
29-September-2001 00:00
Hi Matt,
I like the way you have done the rear disk brakes. I am currently putting a Nissan Cherry Turbo engine in my pick-up, I am going to be doing a rear disk brake conversion (simmilar to yours. If you were to put the callipers ontop of the radius arm do they foul against the shocks? i am going to be running coil overs all round you advises would be greatly appreciated.
Peter
commited@eircom.net
13-January-2002 00:00
Kad do a disc conversion for £581
prwilkinson@netscape.net
31-January-2002 00:00
I have ordered a KAD set-up, can't wait to get my grubby hands on it!
malvdog_99@hotmail.com
30-April-2002 00:00
I have heard (and seen pics)on message boards of people using 4mm thick M/C or kart discs and and M/C calipres. Much liter than some proposed systems using ford discs calipres etc but it probably will take a bit more fabrication etc.
try2contactme@hotmail.com
07-May-2002 00:00
Take a look in the Kit car mags at GTMs Kit cars... theu use Mini Frontends as rear ends .. I did one ages ago and used Fiat X19 rear allipers with some "top hats" to make the pistons longer
adamtoggers@aol.com
29-July-2002 00:00
Your mini is a brilliant bit of mechanical wizardry, but do you have any sujestions on how to fit rear disc brakes to a 1970 Truimph GT6 mark 2 Rotoflex if you do please let me know as I am a bit frustrated
nova1.6gte@bellisnet.freeserve.co.uk
10-August-2002 00:00
With regards to hydraulic handbrakes:
It's my understanding that they are legal for road use providing they have a mechanical latching mechanism (ie emulate tha ratchet mechanism of a cable handbrake system). You only need to consider the rally cars, they use a three cylinder brake system with their 'fly-off' handbrakes but still need to be road legal (even the WRC cars do) and so use a wedge (for want of a better word!) to hold the handbrake on. Check out the Demon Tweeks Motorsport catalogue for a better idea of how it looks.
Feel free to correct me if I'm wrong, Danny.
mini_pickup_turbo@hotmail.com
07-October-2002 00:00
What about using VW/Peugeot rear calipers they have an intergrated manual handbrake, will they fit is the only question?
BERTSMINI@AOL.COM
09-October-2002 00:00
HEARD THAT EARLY MK1 GOLF GTI DISCS AND CALLIPERS WORK,I WILL BE TRYING THESE ON MY 16V CONVERSION.
chibi_kitty2002@yahoo.com
31-October-2002 00:00
How much does the Ford Fiesta weigh?
pumdriver@aol.com
27-November-2002 00:00
Did you try Front BX citroen Calipers...
The Hand brake is on the front wheel onthis shitty cars...
Best regards, Good job...
nitthinkarkal@indiatimes.ocm
02-January-2003 00:00
notes regarding car chasis design using
FEM
jukka.harkola@polartest.fi
16-January-2003 00:00
The best option ´that I have seen so far is in late ´90s small 16V Citroen/Peugeot models. They have a very slim rear calibers that mount at the stub axle height, and have the hand brake level at about where the mini cable is. Furthermore, the size looks like it will not foul the subframe. I have fitted a pair of VW calibers to my Morris Minor but they are a very tight fit into a mini plus the hand brake cable is above the wheel centreline, not below as it should be.

Jukka

playtime@xtra.co.nz
07-March-2003 00:00
You could look at using the rear brake setup, off an early Austin A35,as the rear brakes are operated by cable to hydraulics ???
playtime@xtra.co.nz
07-March-2003 00:00
I mean just to use the hand brake setup which is lever or cable to hydraulic,which then operates cable ,
It must be legal ,they built hundreds of thousands of them ???
reg.summers@euphony.co.net
23-August-2003 00:00
have you thought of using the rear brakes from a peugeot 205 1.9 GTI this brake system must be legal and could possibly fit
john.auty@talk21.com
04-October-2004 00:00
you can buy a rear brake conversion kit from minimania.com