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CUB 16V

g40 rear discs?

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CUB 16V

does anyone know of a conversion that can be done to fit rear discs on a g40? i heard that a mk 2 gti rear beam will fit??

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DKnight

hmmm, i have discs brakes on my G40, an easy mod really, just get some mk2 golf stub axles, they bolt straight on, then discs etc to match, and the mk2 calipers brakes etc fit aswell, but ideally get some mk3 ones they work better, or mk4 i think? (best check I'm not sure)

All just bolts on, only thing that needs making to fit is handbrake cables.

But general braking gains, are minimal if none, only gain is service time, as drums are a shit to do....

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DKnight

oh and whoever said that a mk2 gti rear beam will fit, I'm hoping they were trying to tell you the stub axles fit, and their point got confused.

But if not please stamp "i know nothing about cars" on his forehead to warn others

:D

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gofasterpinch

hmm not quite as simple as people make out if you use mk4 calipers they dont fit under 13" wheels and you need mk4 pads with mk2 discs, mk2 carriers and mk2 stub axels. i used mk3 golf handbrake cables suitably shortened and some motorbike solderless nipples drilled out to suit. the cables are quite easy really, mine are a hybrid of standard polo and mk3 golf cables essentially

oh and you WILL need a 22.2mm master cylinder off a 16v golf to match otherwise you wont push any fluid through the rear calipers

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CUB 16V

cheers guys

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jez1272gt

As the lads above have stated pretty much,

I'm using,

Golf II rear stub axels

Golf II rear wheels bearings

Golf II rear carrier brackets

Golf II rear solid discs

Golf IV rear calipers (for 10/12mm solid discs - aluminium)

Golf IV rear pads

Custom handbrake cable

Custom rear braided hoses

I'm using a brake balance bar set up so i'm removing the servo and using two wilwood m.cylinders of approriate size (one front, one rear) , also removing the load approtioning valve as my car will be fully stripped, corner weighted and no load variance other than fuel... but as said above, a normal system will need to be speced with a 22.5mm from a golf or vento!

As stated above also, the rear disc conversion will not give much if any gain in efficiency but many prefer the ease of service and also the asthetics of discs.

Another aspect to look into is wether or not there are any weight gains from using discs over drums. I suspect that the drums are lighter than the disc set up and even if they are not, due to the caliper sitting at the rear end of the disc, i would expect the unsrung weight to increase due to the centre point of load?!

Obviously the effects of unsprung weight is important (especially to such a light vehicle as the mk3 Polo), an increase in this weight should be as minimal as possible to retain the handling characteristics..

Hope this helps..

Edited by jez1272gt

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gofasterpinch

whoever says that the disc conversion is no more efficient is full of rubbish. they are far more efficient the back end of my car is massively over braked for its weight.

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hayesey

I guess what they mean is that the standard drums offer plenty of braking effort for the back end of a mk3 polo but yeah I agree with you, discs and calipers have more braking force than drums. Otherwise car manufacturers would probably still put drums on the front.

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Brownyg40

I think you mean progresion (with discs)

they still use drums on lories and they are stopping 40 tonnes

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gofasterpinch
I think you mean progresion (with discs)

they still use drums on lories and they are stopping 40 tonnes

air brakes :lol:

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jez1272gt

lol, what i meant was that £ for £ you will not be getting a better efficiency over drums. The difference may be noticable but nothing to write home about in my opinion..

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gofasterpinch

well i think mine were well worth the money! they look smart, easy to service, and my hydraulic handbrake is lethal

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pete_moore16

disc brakes are less efficient thn drum brakes because drums have a self servoing affect. what this means is as the brake is pressed the drum drags the leading edge of the shoe towards the drum making the car stop better where as discs dont have this effect discs are alot more to do with the fact modern cars use servos to make the car more pleasent to drive an like has already been said the ease of service obviously with high performance cars there is also the fact they disperse heat better in the end there are a number of reasons but if u take a car such as an old mini some have no servo and the ones with drums all round stop much better thn the discs that are on the coopers sorry for my rant been studying this at college thought the information was needed lol

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MikeyMK

If you need grippier rear brakes,you can just fit the bigger drums from a MK3 Golf,as i have. Wider too,they've far more surface area and are easy - no custom handbrake cables,they're a straight fit.

I dont know why people find them a problem to work on,and its not like you'll change shoes regularly anyway.

Heat dissipation isnt a factor in this case,so just cosmetics then.

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gofasterpinch

i was having to change the shoes every 3 weeks......

  • Haha 1

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breadman

Maybe Pinches, but you use your handbrake to turn corners. Most people use the steering wheel!

Disc brakes are far more efficient, there can be no doubt in this. However, I don't think that the mk1-3 Polo will stop any better with discs on the back - at least not on the road, the rear brakes do very little work anyway. They do even less when the car interior is stripped out like a lot of them on here.

If you improve the efficiency and bite at the back it'll increase the likelyhood of locking up. You can balance this out with an adjustable bias pedal box, but then you might as well have left them alone in the first place - unless you have fitted larger brakes on the front first.

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jez1272gt
Maybe Pinches, but you use your handbrake to turn corners. Most people use the steering wheel!

Disc brakes are far more efficient, there can be no doubt in this. However, I don't think that the mk1-3 Polo will stop any better with discs on the back - at least not on the road, the rear brakes do very little work anyway. They do even less when the car interior is stripped out like a lot of them on here.

If you improve the efficiency and bite at the back it'll increase the likelyhood of locking up. You can balance this out with an adjustable bias pedal box, but then you might as well have left them alone in the first place - unless you have fitted larger brakes on the front first.

^^Exactly what i am in the process of doing, 256mm Wilwood 4's up front with discs at the rear with an adjustable brake balance bar.. One mc for the front, one for the rear (both suitably specced) and then use the adjustment of the balance bar to get the feel at the back perfect!!

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breadman

That sounds a very nice setup jez. Expect your rear pads to have a long life!

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Guest G-spot

I believe that Porsche use drilled/vented drums on the 356's which would certainly be effective at clearing brake dust from tyhe drums...... any thoughs out there..?????

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VeeDubGeezer

i think Brembo used to do "sprira" drums with groves in the drums (and may still do)

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KiZ

yer - but discs look kool as fuck!

i used a mk2 golf setup which bolted straight on - and then used an audi TT handbrake lever with a3 cables - which involved modification of the floor.

why?? just coz my interior allowed me to do it - but i was initially going to just use the original lever with modified drum cables.

might be worth someone making up a set of the cables to allow people to do the conversion as there would be a lot of interest by the sounds of it.

id do it myself but i just dont have the time

KiZ

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gofasterpinch

the cables are EASY

buy mk3 golf cables shorten the outers to suit

shorten the inners and use motorbike clutch cable solderless nipples JOB DONE it cost me £15!!!

oh and:

IMG_3035.jpg

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TomW
hmm not quite as simple as people make out if you use mk4 calipers they dont fit under 13" wheels

do mk2/3 golf rear calipers fit under 13s?

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LiamnBully
hmm not quite as simple as people make out if you use mk4 calipers they dont fit under 13" wheels and you need mk4 pads with mk2 discs, mk2 carriers and mk2 stub axels. i used mk3 golf handbrake cables suitably shortened and some motorbike solderless nipples drilled out to suit. the cables are quite easy really, mine are a hybrid of standard polo and mk3 golf cables essentially

oh and you WILL need a 22.2mm master cylinder off a 16v golf to match otherwise you wont push any fluid through the rear calipers

Do you need 16v golf master cylinders because your using mk4 callipers? or do you need a master cylinder if your using mk2 calipers aswell. thanks

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gofasterpinch

the cast iron calipers are a bit skinnier so fit under 13s.

You will need the 22mm master cylinder with any rear disc conversion, purely because the pistons are so much bigger and the standard MC doesnt shift enough fluid

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