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Mk2 Golf GTi rear brakes 
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Post Mk2 Golf GTi rear brakes
I know a few people have tried various back brakes, but I'm sticking this here to show how, I'm going about it.
I'm using a set of MK2 Golf GTi rear brakes, the later cars have different calipers but I believe they would work.
I've had them squirreled away now for a while, as I took them when I saw them in the scrapyard.

Cleaned and painted, replace one bleed nipple.

Image


First the difference between standard Mini flanges and Metro "Vented" flanges, I refused to pay the Turbo premium, as they are the same part.

These from Rimmer Bros

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A few minutes to remove the extra lugs and we are good to go.

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Quick measure to show difference in size.

Mini flange

Image
Image

And Metro flange

Image
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Quick Maths 34.65 - 25.98 = 8.67 mm of difference not the 20mm I've seen said online

I also use a less that scientific method of measuring between the rear of the disc and the "steering arm"

Image
Image

Mini = 18.75mm
Metro = 27.60 mm
27.6 - 18.75 = 8.85mm, this is without the hub nut torqued up so 0.18mm of give.

So once the Metro flange is on, you have a small gap where the Golf brake carrier will fit.

Image

Next step is to machine up a spacer and move the hole in and drill them 10mm to fit the new bolts.
For reference the Golf uses M10 x 1.25 or M10 fine bolts on the carrier.

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Mon Mar 20, 2017 10:58 pm
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Post Re: Mk2 Golf GTi rear brakes
Watching with interest here. I ran the MGF calipers for a good while and whilst they are spot on and pretty easy to fit to a Mini disc brake hub the handbrake cable position is a real pain now I've got a CG13 engine in there (it's wider than the A-Series). From the pictures so-far these look like they may solve the problem.

Any idea what sort of diameter the piston is? Might give an idea how they will compare with the MGF ones from a hydraulic point of view.

Iain


Wed Mar 22, 2017 2:36 pm
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Post Re: Mk2 Golf GTi rear brakes
Golf piston size = 36mm
MGF piston size = 38mm

Mini front (What I had before) 2 x 20.6mm

remember area of circle = Image

So
Golf = 1017.88
MGF = 1134.11
Mini = 2x333.29 = 666.58

So a bit more fluid per mm of movement.

I have a brake balance bar, and can change master cylinders if needed to adjust the balance/feel a bit.

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Wed Mar 22, 2017 3:44 pm
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Post Re: Mk2 Golf GTi rear brakes
Ok managed to get a little time tonight on the brakes.

Drilled the holes to 10mm and moved them in toward the hub, the top by about 5mm, the bottom by about 10mm
Bolted the carriers up and stuck a pad in.
Could do with a little more inwards, but I'm using hex headed bolts, and there's not enough to swing them around.
If I can find/buy a set of socket headed bolts, M10x1.25 x 30mm then I could gain a little more space.

At the moment the pads just sit fully onto the disc, I would like a little more.

Spacer at the moment is the hi-tech 3 washers method, but this is pretty close to whats needed.
If my memory serves me right a M10 washer is 2mm thick, so 6mm spacer required.

Image

Image

Image

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Fri Mar 24, 2017 12:38 am
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Post Re: Mk2 Golf GTi rear brakes
Ken555 wrote:

remember area of circle = Image



Heard a joke about this..... "It's wrong,,,, pie are round - _bread_ are square"

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Fri Mar 24, 2017 5:44 pm
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Post Re: Mk2 Golf GTi rear brakes
Managed to get a set of cap head bolts, and along with removing a little of the fillet at the back, I have managed to get all the pad on the disc.

Made up a couple of spacers, hewn from a bit of 0.176" / 4.5mm steel plate.
The could of been smaller, as only the lugs touch, but I felt it was easier in one piece, to fit.

Image

Wait for the paint to dry, then bolt them into place and see how it goes.
Will make up a short M10 to 3/8" pipe, to test, and order up a custom flexi if/once it works.

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Tue Mar 28, 2017 12:04 am
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Post Re: Mk2 Golf GTi rear brakes
Any chance of a picture of the hub and what the mounting holes look like now?


Tue Mar 28, 2017 10:56 am
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Post Re: Mk2 Golf GTi rear brakes
ibrooks wrote:
Any chance of a picture of the hub and what the mounting holes look like now?


Will do, hopefully will assemble one side tonight and will grab a pic then.

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Tue Mar 28, 2017 11:53 am
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Post Re: Mk2 Golf GTi rear brakes
These are the holes as they stand.

Image

Spacers fitted

Image

Didn't take a picture but the carrier is dead centre on the disc.
Not sure how big a problem it would be on a single pot, sliding caliper anyway.

Plenty of clearance for the wheels I have, will try one of my Minilite copies on later.

Image

Need to make up the brake pipes and move the handbrake cables over from the other car.

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Last edited by Ken555 on Thu Mar 30, 2017 10:33 pm, edited 1 time in total.

Tue Mar 28, 2017 7:25 pm
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Post Re: Mk2 Golf GTi rear brakes
Looks like the holes need to move quite a bit more than for the MGF calipers not sure I'd be comfortable with the mounting lug left so thin.

It's not too critical for the disc to be central in the carrier - as you say the sliding caliper will compensate for a mm or two in either direction.

Wonder if the Golf caliper would fit on the MGF carrier - you just know it would be too easy.


Wed Mar 29, 2017 2:25 pm
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Post Re: Mk2 Golf GTi rear brakes
They are moved in approx 6mm, but no loss of thickness, but I'll keep an eye on it.

Handbrake cable modifications next. Looked at using the Golf Cables and decide to go with the Coupe (Morris Minor ?) cables.

Chopped the nipple open with a cold chisel, just to get a clean end, wasn't convinced I could clean the end from the years of grease and grime.
This allowed me to pull the cable back inside the outer spiral, and chop approx 30mm off.

Image

Welded a washer on 12mm from the end, and welded on a couple of nuts as a replacement nipple, the first was squashed in the vice to grip the cable, the second was welded to the splayed end of the cable.

Image

Final, temporary thing was to make a short M10 Male to 3/8" female adapter pipe, this is to keep me going until I get a custom flexi pipe made.
Planning to soldering the bracket to the pipe, that's why it's copper.

Image

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Thu Apr 06, 2017 10:06 pm
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Post Re: Mk2 Golf GTi rear brakes
Ken,

Why the two large spacers under the Rossabits arm? Is this some subtle geometry tweak?

Steve


Fri Apr 07, 2017 9:32 am
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Post Re: Mk2 Golf GTi rear brakes
To get rid of bump steer at the rear.

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Fri Apr 07, 2017 1:17 pm
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Post Re: Mk2 Golf GTi rear brakes
Just as a final remark on this topic.

MOTed the car (was on my 4th tester before I got one that fitted in the car, in fact he got the youngest tester/mechanic who runs a drift car, to get it in/out of the test bay) and the brake test figures were.

Front 180 kgf / 181 kgf - wheels locked
Rear 136 kgf / 137 kgf - wheels locked

Total service - 634 kgf

Parking - 104 kgf / 103 kgf
total 207 kgf - Wheels locked.

In every test the wheels locked before the max brake force was recorded, but as it was the tester thought that 106% !/ 34% efficiency was good enough, pass limit is 50% / 16 %

I gave him the weight as 600KG so maybe a bit optimistic, planning a trip to the local weighbridge to check it out.

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Thu Jun 29, 2017 10:57 pm
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