RS2 Brake Upgrade - Help Please

[minim]

Measure the bolt pitch. If its 1.5mm and the bracket is different its probably a 1.75mm pitch. Difference between fine and coarse. Difficult to measure unless you just happen to have a known pitch bolt to compare!

Yeah its hard to measure inside the threads. It just felt like the bolt moved a bit hard when I tried to fit it by hand and it looks like bigger pitch on the threads on the bracket. Will measure and test with other bolts when I'm in the garage.

[minim]

Test mounted now. The calipers from Hansen Motorsport is using 1.75mm pitch on the threads and stock bolts/Porsche 996 bolts are using 1.5mm pitch. I'm glad I only tested with finger tithing and not using any tools so I ruined the aluminium caliper brackets.

I had 12.9 umbraco bolts with 1.75mm pitch and perfect length in my garage so I got it mounted to test the clearance to rims and how it fit on the disc. It looks ok but it's not a perfect lineup. As this photo shows the calipers could be moved in another 1,35mm so the clearance was 2.65mm on each side. My reference points are the "studs" that are holding the brake pads since they are what is going closest to the disc. Anyone think this clearance matters a lot? Ideally the disc/calipers should not move at all so no clearance is needed but with hot discs I guess they do expand a bit. More than 1mm?

[twoqu]

Personally I would take the time/effort to centralise the disc in the caliper.
As suspected, clearly those brackets were not designed for the application. Fortunately you can use a washer/shim to get the clearance.
Guess the brackets were in effect for the S2 using A8 disc which would sit further inboard then the stock items. Oh well as long as they are ok radially you should be able to get away with it.

[minim]

Personally I would take the time/effort to centralise the disc in the caliper.
As suspected, clearly those brackets were not designed for the application. Fortunately you can use a washer/shim to get the clearance.
Guess the brackets were in effect for the S2 using A8 disc which would sit further inboard then the stock items. Oh well as long as they are ok radially you should be able to get away with it.

Yeah could shim it but I'm not sure thats a better solution if the clearance doesn't matter. Shim would make it a not so good "connection" but it will still be good enough. What comes to my mind is the KISS principle and not adding another weak point if it's not needed. The pads and piston will adapt to the clearance so they will have exactly the same force as if it was aligned.

[twoqu]

Well its your car!
Let me put it like this. When you buy an AP Racing kit they supply a range of shims to allow precise centralisation of the disc within the caliper. Thats how significant it is.
Do some research to see what the drawbacks are. The obvious one being that one set of pistons is more likely to pop out than the other when the pads get worn!

[minim]

Well its your car!
Let me put it like this. When you buy an AP Racing kit they supply a range of shims to allow precise centralisation of the disc within the caliper. Thats how significant it is.
Do some research to see what the drawbacks are. The obvious one being that one set of pistons is more likely to pop out than the other when the pads get worn!

Ok I'll look into it I'm pretty sure 1,35mm is to little to make the pistons pop but there could be other things like changing the points force (when braking) are on the caliper when it isn't centered. I will see if I get time to machine two shims tomorrow if I got 1,35mm or close plates lying around.

[minim]

Bleh You woke me up abit when you mentioned S8 discs and radially and I realised that I didn't measure this good enough earlier.

Was out in the garage to do some quick measurements else I wouldn't be able to sleep tonight

When looking at the pad from the outside you see that the top of the brake pad isn't in contact with the brake disc.



From the inside showing the same offset as on the outside picture.


From what I see this is how it needs to be adjusted. I'm tempted to ship it back and get something proper done. I could shim it to get the proper centration of the caliper but I would also have to make oval holes to move it 4,5mm towards the centre of the hub to adapt it to a 322mm disc. If I had a 330mm disc it would be a perfect fit

[twoqu]

Again ideally the brake pads should sweep to the very edge of the disc, or within a mm. So that could be accomplished with another shim to space it out radially. Its a bit of a compromise but thats what happens when you adapt different discs/calipers. I thought the 996TT pads were larger than the 993TT. It may well be that the 993TT are deeper so sweep more of the annulus but overall have less swept surface.
Of course all these issues would have been solved if there was such a thing as correct brackets, which there appears to be subject to cost and availability!
I suppose one issue is whether any of this helps in terms of clearance within the stock wheel.

[minim]

Again ideally the brake pads should sweep to the very edge of the disc, or within a mm. So that could be accomplished with another shim to space it out radially. Its a bit of a compromise but thats what happens when you adapt different discs/calipers. I thought the 996TT pads were larger than the 993TT. It may well be that the 993TT are deeper so sweep more of the annulus but overall have less swept surface.
Of course all these issues would have been solved if there was such a thing as correct brackets, which there appears to be subject to cost and availability!
I suppose one issue is whether any of this helps in terms of clearance within the stock wheel.

Can't use spacers for getting it closer to the centre of rotation. This adapter seems to be made for 330mm discs and I'm using only 322 discs so that is why the pads (from 996) is comming 4 to 4,5mm to far out. I don't think it is a issue of wrong pads but I could be wrong of course.

To get the caliper down those 4mm it should for the pads to fit perfectly on the disc surface I think it's just to make the holes that mounts to the featherbone (hole in adapter that is for the bolt that is fitted to the car, not sure about the english word for that) shaped like a "0" instead of "o" so I got some slack to adjust them on there. I do not want to machine off 4mm of the flat that the caliper is mounted on as that part is only 13mm thick and holding threads so there will be only 9mm of threads left on a aluminium bracket and that's not great for the strenght. The easiest thing would be to get a couple of 330mm discs and replace the hub/bell on it with the original RS2 322 disc hub :=)

[twoqu]

To get the maximum leverage the pads need to sweep the outside of the disc, the furthest from the centre. Moving the pads towards the centre decreases the leverage in effect. It happens on the S2 as well when the A8 disc are used that there is a portion of the disc that is unswept by the pad.
I reckon these brackets were designed for A8 314X30mm disc on an S2. Deduct 4mmX2 from 322mm! To be honest I don't even like the lack of support of the caliper itself but thats another issue! The biggest issue is that the retailer sold you items that are not fit for purpose other than the fact they just happen to have the bolt holes in the right places. I did try to warn you previously that unless they were confident to state exactly what disc these fitted then you were in trouble. Now you have an even longer frustrating wait to either source or produce correctly specced ones.

[twoqu]

The only way you are going to get everything correct is to use the matching components. Unfortunately you cannot do that. Had Porsche had the foresight to make the 996TT disc with the correct offset it would have been a different story. The options have been discused. The 965 discs (or 322 two piece) and 996TT calipers seem to be the only solution within a stock wheel without spacers.
The only option would be to go back to the 993TT Big Red calipers with the potential corrosion issues but then everything would match and you could use the RS2 original brackets. No one would be able to tell the difference!

[minim]

To get the maximum leverage the pads need to sweep the outside of the disc, the furthest from the centre. Moving the pads towards the centre decreases the leverage in effect. It happens on the S2 as well when the A8 disc are used that there is a portion of the disc that is unswept by the pad.
I reckon these brackets were designed for A8 314X30mm disc on an S2. Deduct 4mmX2 from 322mm! To be honest I don't even like the lack of support of the caliper itself but thats another issue! The biggest issue is that the retailer sold you items that are not fit for purpose other than the fact they just happen to have the bolt holes in the right places. I did try to warn you previously that unless they were confident to state exactly what disc these fitted then you were in trouble. Now you have an even longer frustrating wait to either source or produce correctly specced ones.

I think we misunderstand eachother. The problem isn't that they are not far enough out but they are going on the outside of the breakdisk (to far out). Look at the picture again where you can see that they do not go far enough in on the breakdisc (towards centre of wheel) and on the outside it sticks out of the disc with 4mm-4,5mm or so. This means that I need to get the caliper in towards the centre of the wheel to get the brake pad to touch the whole brakedisc as it should. I did send a email with pictures to Hansen montorsport now asking what to do. I can return them so it was just ordered to see how it fitted. A lot easier to do that within Norway since I do not have to pay VAT/customs fee for it that's why I didn't want to do the test with the VRS adapter.

I need to wait to work on it anyways as I'm going out for 14 days of work again so won't see the car then I should find out what to do quickly tho so I can get the parts when I get back home tho. Atm I'm even more tempted to get them machined at my spec so I can get a perfect fit without trying 3-4 different adapters first just to find out that none fit.

I'm pretty sure that there is a lot of RS2's out there in Norway driving around with this adapter without knowing that they didn't really fit the car as it should. I bet they even use the 1.5mm pitch bolts into the 1,75mm pitch threads so it sits even worse

[twoqu]

AH! So the pad is overhanging or sticking out past the edge of the disc. Must be my eyes. The one side of the pic I am looking at it appears to underhang. Bit of an illusion or my Meds!
Yep not much you can do then. Its odd as we know the 330mm discs are in the region of 9mm less deep so those brackets woud not even work on them as far as I can tell. I am trying to do the maths but I was wondering if in fact they would work for Jade. That would be very odd, especially as we know he appears to have the Worlds only pair of those discs!

[minim]

AH! So the pad is overhanging or sticking out past the edge of the disc. Must be my eyes. The one side of the pic I am looking at it appears to underhang. Bit of an illusion or my Meds!
Yep not much you can do then. Its odd as we know the 330mm discs are in the region of 9mm less deep so those brackets woud not even work on them as far as I can tell. I am trying to do the maths but I was wondering if in fact they would work for Jade. That would be very odd, especially as we know he appears to have the Worlds only pair of those discs!

I can make the bolt holes oval (0 shaped not o shaped) so I can move the caliper 4mm closer to the centre or make 2mm this way and machine off 2mm on the surface where the caliper is mounted on the adapter. It is doable but it comes with tradeoff in strenght. Will have to look more into it when I'm awake tomorrow as it's to late for thinking now on a saturday evening

That is correct. The only thing I can imagine is that these are made for S2 with some odd discs and has nothing to do with RS2. Maybe the seller tried them on a RS2 and didn't notice or ignored what I have discovered now. It will work and it won't be possible to notice these problems when driving.

They would be perfect for Jade from what I can see. A 330mm disc with the stock RS2 offset will only need 1,35mm spacers on the adapters and it should sit perfect. For the radial mount it now is making the caliper sit approx 4mm to far out. A 330 disc will have 8mm bigger diameter and 4mm bigger radius so it should be correct for a 330mm disc since I'm now using a 322mm disc and measuring that it sits 4mm to far out.

[twoqu]

I didn't like the info from the start! Bit of a ****** trick to sell something safety critical that doesn't fit. As the end user you shouldn't have to modify anything but thats what I was trying to warn about. The brackets must be made to suit the application. The fact they couldn't tell you what discs they were for on the RS2 set the alarm bells ringing.
Oh well, I guess all you have lost at the moment is a bit of time. Send them back and cross Hansen of your Yuletide list.