I know there is a nice brake upgrade available for the 2wd Cosworth, using Focus RS discs together with 4 pot Brembo calipers from a BMW e38 735i.

Unfortunately you cannot use those discs on the 4x4 as the disc offset is too much. So I thought it might be possible to use the e38 calipers with some Hispec or AP discs that fit the 4x4. But it turned out the calipers are also too wide (again due to the disc offset) and will touch the spokes of the wheels.

Does anyone know if there are other OEM calipers that will fit on the 4x4? It seems like all 4 pot calipers are too thick and will have the same problem. Of course you can get some AP or Hispec 4 (or 6) pot calipers that will fit, but I think it will be a lot cheaper to use calipers from a different car. I was also looking at some Porsche Cayenne 6 pot calipers, but cannot find what size it is.

 

Think Reyland does a few cheap options for the 4x4 Marc but i got bored of looking for info in the end for a diy kit so just got a AP kit in the end

 

What AP kit did you get? Looking at the AP site it looks like both the 4 and 6 piston sets have the caliper stick out 57 mm past the disc. That is almost as much as most OEM calipers. I currently don't even have 57 mm between the disc and the wheel spokes. I have only about 50 mm. And with the AP kit you also get 28 mm thick discs, which is again another 4 mm closer to the wheel.

Are there a lot of people having clearance problems with the AP kits on 4x4's, or is it just my wheels that cause the problems (17x8 Hochenheim R, ET35)?

 

I have the 4 pot kit with a 38 et and a 5mm spacer and i had to fit longer studs though

 

I looked into the AP 4 pot kit, but it seems like the caliper will stick out much more. In fact I think I would need to fit 15 mm spacers behind the wheels to make them clear the calipers. And with those 15 mm spacers the wheels would stick out quite far.

So I have been looking into other options and found a set of calipers that may be useful. The calipers of a BMW E38 750i (not the Brembo 4 pots) have 2 pistons, both on the inside of the disc so are still of the sliding type. I'd rather have 4 pots, but the fact it's a sliding caliper means it doesn't need much room between the disc and the wheel. The BMW also runs 334 mm x 32 mm discs, so that also seems good.

The 750i caliper is the one in the middle.



But there is only one problem. The brake pads of the BMW have a pad swept area of 73 mm and the only rotors with bells I can find upto now have a pad swept area of 60 mm. For the inner pad it's probably not really a problem, it just sticks out a bit on the inner side of the rotor. But the outer pad will hit the aluminium bell. And I'm not sure if cutting the inner 1.5 cm of the brake pad is such a good idea...

Other options would be single piece discs from an other car that fit. But those aren't really easy to find...

Anyone know of any options for the discs to use?

 

can't help much with what fits but them 2pot jobs stop my 750i well, for the weight of the car!

 

It seems like brake discs from an Audi TT 3.2 aren't too far off. They are 334 mm diameter, 32 mm thick and 35 mm height. They only problem is that they are 5x100mm PCD and a 65.1 mm centre bore. Drilling them to 4x108mm seems a problem as the disc has more than just the 5 holes in itm which doesn't leave much room for drilling more holes. Besides that I don't know if the 1.8 mm too big centre bore would be a problem.

Would it be possible to get brake discs suppliers to drill a blank disc to 4x108mm and a 63.4 mm centre bore?

 

I've asked a few suppliers and Hispec is able to supply rotors and bells to suit. The only thing I don't know yet is what the price would be. But I can imagine this would be a nice upgrade for all 4x4 cossies. Perhaps if there is a lot of interest they could supply a kit. The rotors I would be using are 335x32mm.

The main problem on the 4x4 is the low disc offset which means there is basically no room for a 4 (or 6) pot caliper unless you have one of the few wheels that provide a lot of room. These calipers are of the sliding type, meaning you only have the brake pad and a relatively thin metal part to hold the brake pad outside the discs surface. I think they stick out about 4 cm of the disc compared to 6 cm for most 4 or 6 pot calipers.

 

I used ap rotars and bells on my Escos with Evo 9 brembo callipers, made all the brackets etc myself, tight squeeze but have been ok for a year or so, no spacers just 63mm studs.

 

Silly question,

Could you use Rover MG discs get the PCD changed and just relocate the caliper?

They are showing:
Dia: 325mm
Height: 35.1mm
Thickness: 25mm
Centre Bore: 64.2mm

Compared to the Cossie:
Dia: 278mm
Height: 35.2mm
Thickness: 24mm
Centre Bore: 63.7mm