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I've moved this up here because it's an interesting conversion.... a lot of people will say "why bother, minis don't need a lot of rear braking" but in the case of engine conversions, we need all the braking we can get

I have a set of Honda rear calipers set aside for my conversion, they're very neat, fit over an S rotor perfectly and very neatly under a 10" Cooper S steel wheel

as you can see here, not hard to do

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That's a interesting conversion. I have done one using the rear calipers and discs off a magna[4 stud wheel] the calipers are aulmin with hand brake lever, but they were still 9" to fit 13" wheels. I used a trailer stub axle machined to fit mini arm. The brgs were the same.
Simon you keep giving us ideas. Get your lathe going and knock some up, you have them almost finished

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I might ask the dude some questions. He probly wont take me seriously because of the distance but it might be worth a shot.

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thats a great idea would be worth the effort of doing a shame ther isnt much info floating around on how that is done.

it's really not complex - it's done in the same way a front drum upright is converted to take a caliper

the trailing arm has 3 threads used to hold the standard backing plate, all that is needed is an adapter plate to mount up the caliper, and fit a rotor to the mini wheel hub, or a different stub axle/hub as David has suggested

and yes David, my lathe is a happening thing, just too much on the go...

here's a honda caliper in an S wheel - I'm planning on using an S rotor because I need CV's at the back, but the caliper is a neat little unit, and a wreckers will sell them for about $30 each. Basically all hondas with rear disks (including late model ones) have the same rear caliper. These came off an early CRX

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And dont forget the other options Simon, like Skyline etc.

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pfft.... you know I don't consider anything that requires a wheel bigger than 10"

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did I tell you that I won a trophy?

So if you went the Honda Disk options front a rear, could you re-drill the hub's/flanges to 100mm PCD (Honda Stud Pattern) and use the bigger 10 or 12mm Jap Studs instead of the 3/8 originals. This would open up your choice of 13" Wheels to basically anything on an 80's or early 90's Jap car?

could you expand on that a little?


I want to do this.

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basically anything that has rear disk brakes could be adapted - like David suggested above, using Magna stuff...

I was given some Skyline rear calipers that were a nice unit, I gave them to Tricky cos they wouldn't fit under a 10" wheel

you need to look for one with a cable handbrake that operates on the caliper - so not from commodores etc. which have a drum brake setup inside the rotor hat for a handbrake.

Notice that ebay one has an ENORMOUS spacer, this is because the hat on that rotor is very short you'd have to see it disassembled to tell what the setup is.

David's solution of using a Magna wheel hub may overcome this

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I went and had a fiddle in the garage, using a Honda caliper (as pictured above) one way to do it would be to machine up a wheel hub to suit an S rotor, to take normal rear wheel bearings. Mount the new hub to the rotor with 4 screws the same way as for a front drive flange - dunno if the stub axle is long enough tho

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What I did for the conversion was to use two trailer stub axles and fit to mini hubs to them with different size taper rollers. One was a std ford inner and the outer was a hi-cap taper roller[not too sure of the id no. got it somewhere]

The original idea was from a set-up that I do for a front disc brake conv. I make a new stub axle to take mini hubs/brgs with a spacer shoulder machined on it to mount the std brake back plate and drum. Just use longer bolts to mount it to the arm. The backing plate can be now positioned to suit the new front track. It gives more clearance for shocker area[coil over shocks] and fair less weight instead of using mini spacer drums.

I agree with the bigger dia. wheel studs. I normally fit 7/16"[holden] or 1/2" [ford] to the discs. It is stronger and easier and cheaper to buy studs and nuts to suit

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Research is the difference between speculation and investment. Anyone who copys some one else will always be second
www.minisprintgt.com

Dicko,

Thats my intention, even though Simon is still in the dark ages with his 10" wheels

Simply, its a matter of machining up a mountig bracket to mount the new Jappo caliper onto the old Mini disc brake hub. Then remachine and redrill the drive flange to suit 4 x 100 pcd and 12mm studs which then opens up a multitude of wheels you can you use.

I will take a pic of my skyline hub (generously donated by Kerr Enterprises) and post. But, as Simon says (pun, ), they will not fit under a 10" wheel. Not many rear calipers will, but Civic/CRX is one that does.

Cheers,
Tricky

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Ok, finally got Photobucket sorted and working (albeit from work: naughty )

Anyway,
Here are some shots of the skyline rear disc and caliper that I intend to use of the Honda-powered, AWD ute conversion that I am doing.

As you can see, the caliper is nothing special, a typical sliding caliper type with single piston. The difference with this and say, a Commodore rear disc caliper is that with the Holden, the park brake is situated inside the hat section of the disc rotor, and operates that same as what a drum would. With this caliper (and the other Jap ones like Simon's CRX one) the handbrake cable actuates a cam, which leverages against the disc pad to grip the rotor. It works very effectively, and is very light and compact with fewer moving parts. Bear in mind that this caliper is not off a GTR, it is a GTS caliper. The GTR caliper is a twin opposed setup made by Brembo, and an awesome bit o' kit!!




And this is the rotor. It is a cast steel unit, with integral hat section as per the norm for mass-produced cars. PCD is 4 x 100, and the stud diameter is 12mm. The rotor diameter is 240mm (or 9 3/8 inches in the old mesurement for those old farts among us that are living in the dark ages ) which is quite large for a rear disc (but then again, the Skyline is a large car). Disc thickness is 9.8mm.




This is the rotor and caliper sitting inside my 13 x 7 Superheavies. As you can see, there is a little bit of room here, but not much. I would say that with this caliper, 250mm (or 10") rotors would be the absolute maximum you could use. If you used slimline calipers, I doubt you would gain any extra. Anyway, this type of setup, and that of Simon's using the CRX setup, would be more than enough braking for the rear end of a Mini, even with a mid-mount RWD setup with more weight over the back axle (actually, it would work better!!)


And this is the gap, about 10mm to the inside of the rim. I am using 14" rims on 4 Paw, so this would be a bit larger (by about 12mm). Large enough to stop small bits of gravel lodging between the brake caliper and the rim and scoring the rim, which is a real issue on tubeless tyres.


Any questions, please ask (Simon)!

Cheers,
Tricky

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