Upgrading to Rear Vented Brakes

[TimmyQ]

Hi all,

 

Just wondering if anyone has experience changing out the solid 272mm rear rotors of most 5E Octavia RS models with the bigger 310mm vented rotors of other VAG cars such as the GTI PP or even the RS 245 etc? I know this requires a caliper, carrier, shield, pad and rotor change. And I know it'll be a marginal performance upgrade at best. Are there any reasons why the RS 245 parts would not just be a straight bolt-on? I know there have been changes to some parts of the rear suspension compared to earlier models, but not sure if that would affect the fit of the caliper/carrier at all.

[TonisT]

Hello,

Tampering with brakes takes more know how than people usually realize. Just throwing on bigger diameter disks to the rear without thinking about front will throw off the whole braking system. You need to maintain bias and you might throw off ABS and stability control systems. You will not gain much with bigger rear discs anyhow except better heat management that you do not need, and might end up with fubered bias and electronics behavior.

If you would do front and rear, then it could be a different story but might require comparing if abs pumps and software's are the same as your car and donor car.

You wanna read up this article: https://www.brakes-shop.com/brakepedia/bbk/abs-and-brake-kit-fundamentals

and maybe brows up little bit more in that site concerning brake kits. Pretty good read.

Edited 27 November, 2018 by TonisT

[fabdavrav]

dead easy swap between MQB platform cars......but the rears are soo over braked even on the estates that its not worth upgrading the rears to PP/R/CCS spec ).......fronts..yes..rears no..

[Chimble]

Just wondering why you feel the need to upgrade. I have done 40 laps of the Nurburgring with my mk3 Octavia and brake performance has never neen an issue. Heat can be a problem but better pads is the answer. The driver is usually the weak link in the chain regarding performance, muself included.

[ChoonDoode]

The fronts do the vast majority of the job of braking. Inertia dictates that.

 

You'd get more benefit from putting on a set of 4 pots on the front than touching the rears.

 

The main question to ask yourself is what are you trying to achieve?

 

As pointed out above, the heat generated from the brakes is an issue. I took my Hyundai i20 around Oulton Park loads of times and I quickly experienced on my 2nd trip there, brake fade and the excessive pedal travel.

That was April and I returned in the following June, equipped now with EBC greenstuff front pads and I'd replaced the stock fluid with Castrol react Dot 4. There wasn't a grooved disc replacement, so I stuck with the standard discs. The return from those upgrades was brilliant though. A better bite from the brakes from the moment you touched the pedal and very little fade throughout the event.

BUT..........because I was getting better performance from the front brakes, it was showing up the tyres for what they were (cheap Nexens). You had to be careful on the final bit of braking (certainly at Cascades and Hissie's) as it did want to lock up (I'd unplugged the ABS sensors, as you don't need ABS on track, just an adaptive right foot).

 

Now this is where it gets important. I threw a set of greenstuff pads on the rear (as I was thinking if the fronts did good, so must the rear) and I could honestly say, they didn't make an ounce of difference. 

[JohnnyType2]

if you want better performance as mentioned decent pads will make a much better option, if its tits and teeth your after get some dimpled rotors and stay well away from grooved (trust me!) as the extra noise can be unbearable. I have grooved & dimpled for 10K miles now and the noise is still there even with brembo pads.

[flybynite]

Yes they fit, all the way back to the MkV Golf R32, anything with a mechanical handbrake (stay away from MQB Audi, VW and Seat as they are electric handbrake) and use suitable (4x4 or 2wd) dust shields,

 

and yes they make a difference. 

 

However rather than just sticking them on you need to be clear what problem you are trying to cure, fade? balance? or just shrinking the gap between disk and wheel for looks. For most problems there are easier and cheaper options.

 

It would help to know what you are starting with, a couple of different front setups have the 272mm rear.

 

I wouldn't worry about the ABS, modern ABS systems (and for a good 10 years now) monitor so many variables and process them so fast that they will cope with most things you can bolt to it and adjust on the fly without batting an eyelid. I have yet to fool one, even when trying

[TimmyQ]

Thanks for the replies. FYI I have the 340x30 fronts (it's a TSI RS). 

 

To be honest, it's 85% aesthetic and 15% performance motivated. So the performance benefit is not really a big deciding factor. I know the rear brakes don't do a lot because I've almost done 70k kms, and my rear rotors and pads pretty well look unused  

 

I just don't know if there are any cheaper options for shrinking that gap between rotor and wheel. Honestly, if the front brakes weren't so wheel-filling it probably wouldn't bother me haha.

[TonisT]

Smaller wheels?

[Redboy]

On 28 November 2018 at 13:19, Chimble said:

Just wondering why you feel the need to upgrade. I have done 40 laps of the Nurburgring with my mk3 Octavia and brake performance has never neen an issue. Heat can be a problem but better pads is the answer. The driver is usually the weak link in the chain regarding performance, muself included.

 

Refreshing to read a pertinent reply, particularly the weak link comment.  Amazed there's been no response stating that Chimble wasn't trying hard enough around the Ring...

[ChoonDoode]

14 hours ago, TimmyQ said:

I just don't know if there are any cheaper options for shrinking that gap between rotor and wheel.

 

I wonder if you could add a bigger bracket, so you could add 310mm discs and keep the same calipers.

 

11 hours ago, Redboy said:

 

Refreshing to read a pertinent reply, particularly the weak link comment.  Amazed there's been no response stating that Chimble wasn't trying hard enough around the Ring...

 

Going around the ring takes some guts. I'd love to go around it, but it's crazy seeing some of the tricks people do. Seen some bad crashes.

Edited 30 November, 2018 by tunedude

[Redboy]

15 minutes ago, tunedude said:

Going around the ring takes some guts. I'd love to go around it, but it's crazy seeing some of the tricks people do. Seen some bad crashes.

 

A bit of courage. Like most things, practice and remaining within skill levels help a lot. Generally people who crash on the Ring are lacking in these.

[Chimble]

11 hours ago, Redboy said:

 

A bit of courage. Like most things, practice and remaining within skill levels help a lot. Generally people who crash on the Ring are lacking in these.

It can become addictive. Like I posted, I have been round 40 times and it scares me every time. It is very narrow, the elevation changes really unsettle the car at speed and many of the corners are blind. A smooth drive is the key, no braking once entering a corner, don't lift off in a corner, trust the car, and as stated above, drive within your limits. Knowledge of the track is key.

I changed my pads for EBC Bluestuff on the fronts and Yellows on the rear. That gave me a good balance.

[flybynite]

22 hours ago, tunedude said:

I wonder if you could add a bigger bracket, so you could add 310mm discs and keep the same calipers.

 

No that won't work, the 310mm rears are vented and 22mm wide. The standard brakes are solid and only 10mm wide . You need the caliper to fit over the disk as well as the correct carrier for spacing. Just use the correct parts, they are ready made and fit.

 

On 30/11/2018 at 05:32, TimmyQ said:

I just don't know if there are any cheaper options for shrinking that gap between rotor and wheel.

 

It is about the cheapest thing you can do, calipers and carriers are available used, disks are standard mainstream bits 

 

However the 340F and 310R take a bit of power to rotate and add to the unsprung mass for the suspension to cope with, patently obvious if you have lifted one, (or dropped it on your foot). If it is effective performance you are after the Boxster 4-pots on 312 fronts and Caddy rear calipers on the 272s is a lightweight progressive solution, proven on track a few times.

[ChoonDoode]

1 hour ago, flybynite said:

 

No that won't work, the 310mm rears are vented and 22mm wide. The standard brakes are solid and only 10mm wide . You need the caliper to fit over the disk as well as the correct carrier for spacing. Just use the correct parts, they are ready made and fit.

 

Worth a try any road...... I forget the disc thickness was different.

 

I've tried before to find the correct parts, but I've always struggled. Ebay has loads of 2nd hand parts, but I wouldn't trust them. If I bought 310mm calipers and carriers, have you any idea what the correct vw / audi part numbers are? I know when I've looked, some have the electronic handbrake and you don't want those ones.

 

 Brake Caliper Performance Kit 310mm VW Golf MK7 GTI R Audi S3 RS3 8V

 

Wasn't sure if they'd be appropriate?

Edited 1 December, 2018 by tunedude

[flybynite]

14 hours ago, tunedude said:

Wasn't sure if they'd be appropriate?

 

No they won't fit (not unless you want to retrofit the electric handbrake) MQB rear calipers DO NOT WORK  (unless the VRS245 ones fit - have not checked since the track width change)

 

You need:

 

Calipers and carriers from a mk5 Golf R32. (There are other cars around that era with the same brakes, most have the V6) They bolt on

 

Dust shields from VRS245/Golf GTiPP if you are 2wd or S38V/Mk7R if you are 4x4. Older dust shields do not fit

 

New stretch bolts etc (should go without saying)

 

15 hours ago, tunedude said:

Ebay has loads of 2nd hand parts, but I wouldn't trust them.

 

Neither do I. Second hand stuff is always stripped, checked and rebuilt with new consumables. Anything marginal is binned and we start again. Only way to do it. Some of what I work with, new parts are NLA and you have to work with second hand.

 

These parts are available new if you want. Dust shields and consumables and cheap enough, buy these new anyway.

 

It is a mighty heavy setup, you really do have to have the need. The ATE front calipers of the R32 are better than the MQB TRW ones and also bolt on but are even heavier.

[shyVRS245]

My advice would be trade up to a 245 and fit HEL braided stainless lines and DOT 5.1 motorsport spec brake fluid (cost me £300) and the braking is epic, confirmed around Snetterton race circuit and have only triggered the hazard lights once when trying really hard.

[ChoonDoode]

1 hour ago, shyVRS245 said:

My advice would be trade up to a 245 and fit HEL braided stainless lines and DOT 5.1 motorsport spec brake fluid (cost me £300) and the braking is epic, confirmed around Snetterton race circuit and have only triggered the hazard lights once when trying really hard.

 

Out of interest, are they hoses intended for a Golf Gti? 

[shyVRS245]

1 minute ago, tunedude said:

 

Out of interest, are they hoses intended for a Golf Gti? 

Not sure because the first one's ordered by AmD would not fit so they were probably sent thinking the Golf PP Gti model and Vrs245 were compatible and probably aren't due to wheelbase/front/rear track differences.

[flybynite]

4 hours ago, tunedude said:

 

Out of interest, are they hoses intended for a Golf Gti? 

 

Most good places can make up HEL brake lines to spec (in any colour you want). If you have a manual I would do the clutch line while you are at it.

 

Put good fluid in it too, but one of the best fluids on the market is Dot4 for good reason

[johnmb]

9 minutes ago, flybynite said:

 

Most good places can make up HEL brake lines to spec (in any colour you want). If you have a manual I would do the clutch line while you are at it.

 

Put good fluid in it too, but one of the best fluids on the market is Dot4 for good reason

Son in Law works for HEL down in exeter , always happy to share details if required 

[ChoonDoode]

27 minutes ago, flybynite said:

 

If you have a manual I would do the clutch line while you are at it.

 

You learn something new everyday. Didn't realise it was a hydraulic clutch. I suppose I've never thought about it.

 

I assume you just get more control, the same as replacing the brake lines, because there is significantly less hose bulge, If any.

[Paulbrown]

I have recently fitted the 345mm front kit and I am just finishing off the 310mm vented rear callipers for fitting.

fronts made a huge difference 

i know mines a MK2 and will be different but if your planning on fitting fatter discs then you will need fatter callipers 

[TimmyQ]

Just a little update:

 

So I did eventually go to the 310 rears from the RS245 but needed the dust shield from a GTI PP since the 245 has the different track and different "wheel bearing housing"/knuckle, so the RS245 dust shield doesn't actually fit. I think the ABS module or something had to be re-routed too. I then went to ATE ceramic pads / ATE plain discs front and rears.

 

What I did want to mention is that a) like I thought, the stopping power doesn't feel drastically different, although I figure the ceramic pads are less 'bitey' than the stock pads; and b) the brake bias is noticeably different with the 340/310 setup. The car feels more balanced on the brakes, rather than being nose-down with the 340/272 setup - although I can imagine this could actually be beneficial in terms of shifting weight to the front axle.

[nidza]

Interesting experience, thanks for sharing.

 

But, what is very important to underline: Ate ceramic pads aren't intended for performance vehicles, but for lifestyle and luxury limousines, as they are silent, make very little dust residue, environment friendly etc. 

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