Of brakes and men.

Robin_Cox said:
And here we have it after months of waiting until the right time to get it done : the 310 (and presumably 312)mm brake set up fits cleanly under 6-spoke SE 16" rims by at least half an inch clear air outside the caliper. I also have new brake discs & pads (standard 256mm) fitted to my project car a week later on the same rims, both sets fitted using braided WG/Hel brake lines, which means I have a direct comparison to how they were previously and the bigger brake setup.

Firstly - in normal commuting - the big brakes feel more progressive - there is very slightly greater pedal travel range as predicted by @DuncanA2 above, but it feels to me as if there is more precision / feel over the pedal movement range. Ironically the pedal now feels almost exactly like the one in my A6 which has 312mm brakes. On my project car, the key thing is more firmness and bite to the brake pedal (unsurprising given the state of the discs / pads that came off it). Both are an improvement in perceived pedal feel, but in different ways.

Herewith a photo of the new setup while I was swapping to winter wheels at the weekend ; they are barely visible when the wheels are in situ which is what I was looking for - I just can't get a good angle to take a photo with the wheels on right now owing to driveway occupancy.

View attachment 88162
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Hi Robin what hub carriers and bearings were used as I've bought the s1 calipers all help appreciated cheers Terry
 
Robin_Cox said:
Bearings were SKF VKBA3569 currently with a very good additional 15% discount on Ebay

www.ebay.co.uk

2x Wheel Bearing Kits VKBA3569 SKF 6Q0407621AH 6Q0407621AJ 6R0407621A 6C0407621 | eBay

Find many great new & used options and get the best deals for 2x Wheel Bearing Kits VKBA3569 SKF 6Q0407621AH 6Q0407621AJ 6R0407621A 6C0407621 at the best online prices at eBay! Free delivery for many products.
www.ebay.co.uk

hub carriers I got these -

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Hi Robin thanks so much for the info much appreciated is there anything else I should know about the conversion or that I need to get back plates etc cheers Terry
 
terryjake1 said:
Hi Robin thanks so much for the info much appreciated is there anything else I should know about the conversion or that I need to get back plates etc cheers Terry
Click to expand...
Depends what you mean by "need to know about the conversion" - by all means ask a question if anything comes to mind. I'm no mechanical expert - I worked out what was needed from a variety of threads here and other reading (detailed in the posts above including the entire parts list and sources), and ultimately having put the pile of parts together, my local mechanic assembled them into a whole then swapped them on.
Back plates were the one thing where I drew a blank. Recommended backplates for the larger discs from the diagrams were obtained from Crewe Audi, and they don't fit - fortunately not that expensive so I've swallowed that one as having sourced the wrong part.

I can definitely recommend the HEL brake lines as well - these were retrofitted onto the other A2s with conventional brakes in place of 20-year old originals and look better at the very least.
 
Robin_Cox said:
Depends what you mean by "need to know about the conversion" - by all means ask a question if anything comes to mind. I'm no mechanical expert - I worked out what was needed from a variety of threads here and other reading (detailed in the posts above including the entire parts list and sources), and ultimately having put the pile of parts together, my local mechanic assembled them into a whole then swapped them on.
Back plates were the one thing where I drew a blank. Recommended backplates for the larger discs from the diagrams were obtained from Crewe Audi, and they don't fit - fortunately not that expensive so I've swallowed that one as having sourced the wrong part.

I can definitely recommend the HEL brake lines as well - these were retrofitted onto the other A2s with conventional brakes in place of 20-year old originals and look better at the very least.
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Hi Robin are the brake lines for an a2 or s1,did you find the correct backplates in the end
 
Robin_Cox said:
Back plates were the one thing where I drew a blank. Recommended backplates for the larger discs from the diagrams were obtained from Crewe Audi, and they don't fit - fortunately not that expensive so I've swallowed that one as having sourced the wrong part.
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The brake plates are all the same on the Audi A2 256mm front brakes, and the VW Polo MK4 239mm/256mm/288mm/312mm front brakes.

I suspect Crewe Audi sent you front brake plates from a different car, such as VW Golf MK4 or Audi TT MK1, which are different.

Do your brake plates look like the photos below which should be correct? Have you got the OEM part numbers of the front brake plates that Audi Crewe sent you?

There shouldn't be any need to purchase different front brake plates with a 288mm or 310mm/312mm big front brake conversion, as the front brake plates from the Audi A2 with 256mm front brakes should fit correctly.

Left front brake plate 6Q0615311D (from Audi A2 with 256mm front brakes)
thumb


Right front brake plate 6Q0615312D (from Audi A2 with 256mm front brakes)
thumb

 
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carlston said:
The brake plates are all the same on the Audi A2 256mm front brakes, and the VW Polo MK4 239mm/256mm/288mm/312mm front brakes.

I suspect Crewe Audi sent you front brake plates from a different car, such as VW Golf MK4 or Audi TT MK1, which are different.

Do your brake plates look like the photos below which should be correct? Have you got the OEM part numbers of the front brake plates that Audi Crewe sent you?

There's shouldn't be any need to purchase different front brake plates with a 288mm or 310mm/312mm big front brake conversion, as the front brake plates from the Audi A2 with 256mm front brakes should fit correctly.

Left front brake plate 6Q0615311D (from Audi A2 with 256mm front brakes)
thumb


Right front brake plate 6Q0615312D (from Audi A2 with 256mm front brakes)
thumb

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don't have a clue - from very distant memory was looking for the ones with a 6R (?) or 3C starting suffix. Whatever they were didn't have the correct bolt-hole pattern to fit the hub carriers, so in the end I stopped worrying about it after experience on a number of cars of the back plate exacerbating corrosion and trapped gravel chip noises on front brake discs. MOT tester wasn't bothered about it being absent as long as the brakes were in good condition so that was that.
 
Just the part numbers were updated, newest are 6R0615311A and 6R0615312A. I installed Topran 116445 and 116446 on my 288s.
 
DuncanA2 said:
I use the Polo GTI WRC combinatioin whithout any issues with the ABS or use of 16 inch rims. If you choose the 288 configuration you will still be able to use 15 inch rims. The 312/310 configuration will need at least 16 inch.
If you go this route it is wise to change the master brake cylinder at the same time. Not necessary but advisable. The throw of the brake pedal will be a tad longer as what you are used to with the original brake setup. For me this was not an issue, because to my experience it makes dosing the brakes more smoothed when applied. Original has the tendency to bite a bit.
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The Audi A2 uses a 22.2mm piston bore in its master cylinder for all models including the 1.2TDI with its small 239x15mm front brakes.

The Polo MK4 and the various clones normally use a master cylinder with a smaller 20.6mm piston bore in their master cylinders, including such cars as the Fabia MK1 VRS 130HP (288x25mm front brakes), Fabia MK2 VRS 180HP (288x25mm front brakes), Polo MK4 1.8 GTI Cup Edition 180HP (310x25mm front brakes).

If anyone was finding their oversize 310x25mm front brakes too sharp they would need to go to a larger piston bore in their master cylinder, not a smaller one. However, as already mentioned the Audi A2 is already using a relatively large 22.2mm piston bore in its master cylinder.

The Polo MK5 came out with a 22.2mm piston bore in its master cylinder, ie. matching the Audi A2's piston bore...so you could say the Audi A2 was ahead of its time...although I suspect the Audi engineers chose the 22.2mm for the Audi A2 because of its light weight where a smaller 20.6mm piston bore could have made the braking too sharp even on the standard 256x22mm front brakes.
 
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carlston said:
The Audi A2 normally uses a 22.2mm piston bore in its master cylinder.

The Polo MK4 and the various clones normally use a master cylinder with a smaller 20.6mm piston bore in their master cylinders, including such cars as the Fabia MK1 VRS 130HP (288x25mm front brake discs), Fabia MK2 VRS 180HP (288x25mm front brake discs), Polo MK4 1.8 GTI Cup Edition 180HP (310x25mm front brake discs.

If anyone was finding their oversize 310x25mm front brakes too sharp they would need to go to a larger piston bore in their master cylinder, not a smaller one. However, as already mentioned the Audi A2 is already using a relatively large 22.2mm piston bore in its master cylinder.

The Polo MK5 came out with a 22.2mm piston bore in its master cylinder, ie. matching the Audi A2's piston bore...so you could say the Audi A2 was ahead of its time...although I suspect the Audi engineers chose the 22.2mm for the Audi A2 because of its light weight where a smaller 20.6mm piston bore could have made the braking too sharp.
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Well that answers that one then. I've got another 312mm setup parts collection with refurbished calipers ready to go on my project A2 once I've saved the pennies - I do really notice the difference now in bite-feel on the brakes between the two Tdi A2s, my A2 with the 310mm brakes described above and my project car on which the brakes are still standard.
 
Robin_Cox said:
Well that answers that one then. I've got another 312mm setup parts collection with refurbished calipers ready to go on my project A2 once I've saved the pennies - I do really notice the difference now in bite-feel on the brakes between the two Tdi A2s, my A2 with the 310mm brakes described above and my project car on which the brakes are still standard.
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Did you keep the brake pad wear warning contact on the 310x25mm brakes?

As shown below, the brake pad wear warning contact cables look the same on both the 256x22mm and 310x25mm brakes...presumably because the 256x22mm and 310x25mm brakes are both ATE brake systems and both from the same generation. Even the length of the cables is the same at 145mm.

ATE 13.0460-7117.2 front brake pads with wear warning contact (256x22mm front brake discs)
1728062996621.png


ATE 13.0460-7122.2 front brake pads with wear warning contact (310x25mm front brake discs)
1728062853931.png

https://www.autodoc.co.uk/ate/956204#brake-pad-set
 
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carlston said:
Did you keep the brake pad wear warning contact on the 310x25mm brakes?

As shown below, the brake pad wear warning contact cables look the same on both the 256x22mm and 310x25mm brakes...presumably because the 256x22mm and 310x25mm brakes are both ATE brake systems and both from the same generation.

ATE 13.0460-7117.2 front brake pads with wear warning contact (256x22mm front brake discs)
View attachment 129490

ATE 13.0460-7122.2 front brake pads with wear warning contact (310x25mm front brake discs)
View attachment 129486
https://www.autodoc.co.uk/ate/956204#brake-pad-set
Click to expand...
From memory, and recommendation from my mechanic, cut the old sensor connector off the old pads, stripped and soldered the wire ends together and plugged it into the pad wear socket to eliminate the error. I'd never had a car previously with wear diagnostics, so going to continue replacements at regular intervals promoted by actually looking at the discs and taking braking feel into account.
 
Robin_Cox said:
From memory, and recommendation from my mechanic, cut the old sensor connector off the old pads, stripped and soldered the wire ends together and plugged it into the pad wear socket to eliminate the error. I'd never had a car previously with wear diagnostics, so going to continue replacements at regular intervals promoted by actually looking at the discs and taking braking feel into account.
Click to expand...

Your mechanic might not have realised that brake pads with a suitable wear warning cable are available for those Audi TT front brake calipers, because it would be quite common for mechanics who do big brake upgrades to be unable to find pads with a plug and play wear warning contact cable...hence I suspect the default mode for them is to simply cut the cable.

On amazon.de (the German version of amazon) it's cheaper to purchase these ATE brake pads without the wear warning contact...as shown in the links below.

ATE 13046070812 front brake pads without wear warning contact 310x25mm (44.54 Euro including shipping to the UK)

ATE 13046071222 front brake pads with wear warning contact 310x25mm (57.41 Euro including shipping to the UK)

I agree with you though, wear warning systems aren't really necessary if you keep an eye on the condition of the brake pads, and these systems don't tell you if the discs are worn out before the pads.

In my post below, I've made a list of OEM part numbers to help anyone thinking of going for the old Audi TT 310x25mm big front brake upgrade. I haven't included information on the steering knuckle (wheel bearing housing), which would also be needed if going from 256x22mm to 310x25mm. 288x25mm discs weigh about 7.2kg each and 310x25mm discs weigh about 7.9kg each...so only about 0.7kg more for each disc.
 
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OEM part numbers for 310x25mm big brake upgrade

ATE 11.9541-9595.2 left brake caliper (54mm piston diameter)
1J0615123B
1J0615123C
1J0615123D
1U0615123
8L0615123
8N0615123
https://www.autodoc.co.uk/ate/955174#brake-caliper

ATE 11.9541-9596.2 right brake caliper (54mm piston diameter)
1J0615124B
1J0615124C
1J0615124D
1U0615124
8L0615124
8N0615124
https://www.autodoc.co.uk/ate/955175#brake-caliper

ATE 11.0230-0451.1 brake caliper carrier (left and right is the same)
1J0615125A
4B0615125A
8L0615125
8N0615125
https://www.autodoc.co.uk/ate/12769955

ATE 13.0460-7081.2 front brake pads (without wear warning contact) (standard brake pads)
1J0698151L
3A0698151
3A0698151A
8N0698151
https://www.autodoc.co.uk/ate/956177#brake-pad-set

ATE 13.0470-7081.2 front brake pads (without wear warning contact) (ceramic brake pads)
1J0698151L
3A0698151
3A0698151A
8N0698151
https://www.autodoc.co.uk/ate/956453#brake-pad-set

ATE 13.0460-7122.2 front brake pads (with wear warning contact) (standard brake pads)
1J0698151K
1J0698151M
1J0698151Q
8N0698151A
8N0698151C
8N0698151E
https://www.autodoc.co.uk/ate/956204#brake-pad-set

ATE 13.0470-7122.2 front brake pads (with wear warning contact) (ceramic brake pads)
1J0698151K
1J0698151M
1J0698151Q
8N0698151A
8N0698151C
8N0698151E
https://www.autodoc.co.uk/ate/956463#brake-pad-set

ATE 24.0125-0123.1 front brake disc (310x25mm, 5/100) (standard version)
6R0615301B
6R0615301E
8L0615301
8N0615301A
https://www.autodoc.co.uk/ate/957594#brake-disc

ATE 24.0325-0123.1 front brake disc (310x25mm, 5/100) (powerdisc version)
6R0615301B
6R0615301E
8L0615301
8N0615301A
https://www.autodoc.co.uk/ate/958232#brake-disc
 
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carlston said:
Your mechanic might not have realised that brake pads with a suitable wear warning cable were available for those Audi TT front brake calipers, because it would be quite common for mechanics who do big brake upgrades to be unable to find pads with a plug and play wear warning contact cable...hence I suspect the default mode for them is to simply cut the cable.

..
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Not my mechanic's problem to be honest. The nicely painted "S1 calipers" I bought had brake pads in them. However, it was clear afterwards that these didn't have the sensor things in them. Caveat emptor. I was able to create sensor negators at his behest as described above. Something I will add : since fitting the 310mm brake system on my main A2, the visible and tactile wear on the disc has been negligible compared to that on the first set of 256mm discs fitted in equivalent mileage - and they weren't cheapos fitted previously. No groove / ridge whatsoever.
 
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