Last MOT it was noted that one of my Bilstein B4 front shocks was showing some minor seepage (it's done 20-odd thousand miles in a couple of years and there are some ropey roads around here so I'm not entirely surprised). They also commented that the front pads (Pagid) fitted at the same time were getting towards needing to be replaced. With that in mind, I thought about getting the same again, and then noticed various threads on here (including @Skipton01 , @A2Steve, @rosscanning and the like) talking about larger discs than the 256mm originals and the parts-bin-specials approaches that can be used to achieve this. I also did some reading on parallel fora on diverse vehicles such as the TT, Polo, and Fabia VRs. The rabbit hole beckoned.
The consensus is that the hub mount (a.k.a knuckle) casting on the A2 features an integral caliper mounting point for the FSIII calipers, so fitting something larger is not directly feasible. However, by swapping these for similar equivalents in the VAG family there are possibilities using Fabia VRs (Polo GTI) parts to get to 288mm discs and on vehicles already similar to this, to 312mm discs (ie., MkI TT) that also have 5x100 hubs but use the larger ATE caliper system. I started to get a little confused at this point because there were some indications that the similar hub carrier component from the Golf IV / MkI TT could also be used - with occasional comments about issues with ABS compatibility that I didn't fully understand - with the quoted advantage that the TT casting has a slightly longer bottom ball-joint mount that means you get slightly less understeer as the outside bottom arm in this configuration doesn't influence the tyre to lose the parallel tread contact surface with the ground under cornering forces as easily. (This is best explained in the Briskoda 230hp build link lower down the page with photos - but I didn't read this article until a couple of days ago).
With all of these half-truths in mind, I priced up and bought a pair of Golf IV hub carriers and some Eicher 312mm discs (in the run up to Christmas there were some silly deals on Ebay outlets for Eurocarparts or their competitors that meant these and other contemporaneous purchases were quite cheap). A set of braided HEL brake lines in black arrived following discussion with Ross. The bearings for the hubs though weren't what I was expecting for the A2 (the 5x100 face is similar but there is an external ABS ring), so I then got cold feet and bought a set of the 6Q Polo hub carriers and the usual SKF 72mm bearings / stub axles, a pair of rusty 312mm carriers to refurbish and some ECR calipers allegedly for Golf IV upgrades along with a kit of seals, pistons and other bits. Various other bolts arrived from TPS, and then the whole lot went in a box in the garage for Christmas.
Nearly 4 months later, here we are again.
Reading various other threads made me decide to stick to VAG oem parts, so I bought an Ebay set of TT 312mm calipers and carriers to refurbish. Minutes later I had an epiphany when browsing 7zap parts lists at the same time as reading a skoda page ( https://www.briskoda.net/forums/topic/43733-312mm-brakes-pictorial/ ) on a similar upgrade because I've always been a little wary that going to 312 may cause clearance issues with 16" SE rims (even though 16" clearly do fit over these brakes on the Fabia VRs - but not all do). I already had the 6Q hub carriers used in the Fabia build thread. I noticed that these same carriers were used on the early 8X S1 (which remains 5x100, unlike the limited edition A1 quattro which has 5x112 hubs), meaning that the lovely black S1 calipers for 310mm brakes I had just seen flash up on Ebay would fit. In a piece of man-maths logic, the 310mm brakes would also fit better under 16" rims than 312mm ones (you cannot deny that 310 is smaller than 312) - and they are already painted, with pads and carriers, so I wouldn't have to refurbish the other carriers before being able to use them.
The next question then arose - what is the ABS issue that has been mentioned but not explained in what I've read elsewhere. For this, we need to compare the 6Q (Polo) part with the 1J / 8N (GolfIV / TT) part . The 6Q part (with caliper attached) is on the left ; the Golf IV part is on the right. The caliper will attach to both. You can see some small differences in the location of threaded holes for the brake disc shield, but other than that these parts are broadly similar in most of the major dimensions. However, the lower image shows us what the problem is. On the polo part (left), there are two holes machined into the casting of the bearing housing itself - one passing all the way through to the bearing, the other threaded into the casting. This is the location of the ABS sensor in the 6Q part, and there isn't one on the GolfIV part. A skilled machinist would probably be able to drill and thread two similar holes - but it is when feeling this around this area and then use calipers that you realise the second difference : the 6Q casting wall is slightly more than 2mm thicker than the Golf one, and the bearing housing diameter is just shy of 72mm on the inverted calipers. Consequently, the 72mm bearing will slide all the way into the Golf housing (just under 74mm) and rattle around where you need to press it into the Polo component. So it wouldn't work, unless you get (the slightly larger) Golf IV / TT bearings, whatever ABS sensor is used on that car and then presumably also more mucking about as well.
From another Skoda thread (https://www.briskoda.net/forums/topic/470429-230bhp-dad-wagon/) who tried that approach to begin with - it was possible to cobble something together, but resulted in all sorts of warning lights and daft things like the fans not working properly. In that particular example, they ended up using the S1 (8X) bearing carrier which has the same modified geometry for the ball joint as the TT to give the grip advantages when cornering but also features the ABS sensor location seen here - and on paper that could be an interesting parts choice for someone wanting an A2 more compatible with lowered springs, which I don't.
The ABS sensors have two reference numbers - WHT003861 and WHT003860. These are the same as the 6Q927803B / 6Q927804B components on the A2, but for more recent models they seem to use the WHT code instead.
This is where I've got to so far. This is the first time I've prepared a (genuine) project thread starting something from scratch rather than just fixing stuff, even if my posts are normally quite rambling and verbose at the best of times.
The consensus is that the hub mount (a.k.a knuckle) casting on the A2 features an integral caliper mounting point for the FSIII calipers, so fitting something larger is not directly feasible. However, by swapping these for similar equivalents in the VAG family there are possibilities using Fabia VRs (Polo GTI) parts to get to 288mm discs and on vehicles already similar to this, to 312mm discs (ie., MkI TT) that also have 5x100 hubs but use the larger ATE caliper system. I started to get a little confused at this point because there were some indications that the similar hub carrier component from the Golf IV / MkI TT could also be used - with occasional comments about issues with ABS compatibility that I didn't fully understand - with the quoted advantage that the TT casting has a slightly longer bottom ball-joint mount that means you get slightly less understeer as the outside bottom arm in this configuration doesn't influence the tyre to lose the parallel tread contact surface with the ground under cornering forces as easily. (This is best explained in the Briskoda 230hp build link lower down the page with photos - but I didn't read this article until a couple of days ago).
With all of these half-truths in mind, I priced up and bought a pair of Golf IV hub carriers and some Eicher 312mm discs (in the run up to Christmas there were some silly deals on Ebay outlets for Eurocarparts or their competitors that meant these and other contemporaneous purchases were quite cheap). A set of braided HEL brake lines in black arrived following discussion with Ross. The bearings for the hubs though weren't what I was expecting for the A2 (the 5x100 face is similar but there is an external ABS ring), so I then got cold feet and bought a set of the 6Q Polo hub carriers and the usual SKF 72mm bearings / stub axles, a pair of rusty 312mm carriers to refurbish and some ECR calipers allegedly for Golf IV upgrades along with a kit of seals, pistons and other bits. Various other bolts arrived from TPS, and then the whole lot went in a box in the garage for Christmas.
Nearly 4 months later, here we are again.
Reading various other threads made me decide to stick to VAG oem parts, so I bought an Ebay set of TT 312mm calipers and carriers to refurbish. Minutes later I had an epiphany when browsing 7zap parts lists at the same time as reading a skoda page ( https://www.briskoda.net/forums/topic/43733-312mm-brakes-pictorial/ ) on a similar upgrade because I've always been a little wary that going to 312 may cause clearance issues with 16" SE rims (even though 16" clearly do fit over these brakes on the Fabia VRs - but not all do). I already had the 6Q hub carriers used in the Fabia build thread. I noticed that these same carriers were used on the early 8X S1 (which remains 5x100, unlike the limited edition A1 quattro which has 5x112 hubs), meaning that the lovely black S1 calipers for 310mm brakes I had just seen flash up on Ebay would fit. In a piece of man-maths logic, the 310mm brakes would also fit better under 16" rims than 312mm ones (you cannot deny that 310 is smaller than 312) - and they are already painted, with pads and carriers, so I wouldn't have to refurbish the other carriers before being able to use them.
The next question then arose - what is the ABS issue that has been mentioned but not explained in what I've read elsewhere. For this, we need to compare the 6Q (Polo) part with the 1J / 8N (GolfIV / TT) part . The 6Q part (with caliper attached) is on the left ; the Golf IV part is on the right. The caliper will attach to both. You can see some small differences in the location of threaded holes for the brake disc shield, but other than that these parts are broadly similar in most of the major dimensions. However, the lower image shows us what the problem is. On the polo part (left), there are two holes machined into the casting of the bearing housing itself - one passing all the way through to the bearing, the other threaded into the casting. This is the location of the ABS sensor in the 6Q part, and there isn't one on the GolfIV part. A skilled machinist would probably be able to drill and thread two similar holes - but it is when feeling this around this area and then use calipers that you realise the second difference : the 6Q casting wall is slightly more than 2mm thicker than the Golf one, and the bearing housing diameter is just shy of 72mm on the inverted calipers. Consequently, the 72mm bearing will slide all the way into the Golf housing (just under 74mm) and rattle around where you need to press it into the Polo component. So it wouldn't work, unless you get (the slightly larger) Golf IV / TT bearings, whatever ABS sensor is used on that car and then presumably also more mucking about as well.
From another Skoda thread (https://www.briskoda.net/forums/topic/470429-230bhp-dad-wagon/) who tried that approach to begin with - it was possible to cobble something together, but resulted in all sorts of warning lights and daft things like the fans not working properly. In that particular example, they ended up using the S1 (8X) bearing carrier which has the same modified geometry for the ball joint as the TT to give the grip advantages when cornering but also features the ABS sensor location seen here - and on paper that could be an interesting parts choice for someone wanting an A2 more compatible with lowered springs, which I don't.
The ABS sensors have two reference numbers - WHT003861 and WHT003860. These are the same as the 6Q927803B / 6Q927804B components on the A2, but for more recent models they seem to use the WHT code instead.
This is where I've got to so far. This is the first time I've prepared a (genuine) project thread starting something from scratch rather than just fixing stuff, even if my posts are normally quite rambling and verbose at the best of times.