BREMBO BRAKES

[jimbo1234567]

Ive had to do an overhaul on my front brakes due to the pads becoming metal on metal with the discs. the rs4 has some non standard calipers fitted which i think are porsche gt3 spec brembo 6 pots, when i took the pads out i found that the leading edge (bottom)were worn down to the metal and the top of the pads had still 5mm of pad left.the discs have now been skimmed and whilst putting it all back together with some new pads im finding that bottom of the caliper sits fine with the outside edge of the disc sitting level with the edge of the pad but the top of the pad is a good 3mm out making the pad over hang the inside edge of the disc and this can be seen by the way the pad has worn in the photos.
Looking at the calipers i noticed that the pots are different sizes bottom being 35 mm middle being 30mm and top being 25mm which will explain a stronger braking force at the bottom and more pad wear.
are the calipers the wrong way round and should the larger piston be at the top, the reason i ask this this that the writing on the caliper is upside down and this is the same both sides and the bleed nipples and link pipe could easily be swapped round, do the calipers come as a kit and need to be built up
lastly the flexi hose goes in at the middle of the caliper so again could easily be swapped over
could these have been fitted wrong , any help on this much appreciated as to me this is the most important part of the car. jim

[jimbo1234567]

photo

[ChipHazzard]

Jimbo,

It might be worth checking that none of the pot's are seized as I had a similar problem with the 6 pot's on the front of my motorbike which caused the pads to wear in a similar manner, I ended up stripping and rebuilding the cailpers. the quickest way to check is to take the caliper off and leave the pads in then gently press the brake pedal and make sure they move out evenly

HTH

Mike

[jimbo1234567]

all the pads move freely. but the other thing i noticed is as the pads wear in their triangular fashion the pistons in the caliper will not be sitting squarely on the pad which may cause them to stick?????????

[jimbo1234567]

just had a thought . do porsche mount the calipers in front of the disc . if so the small pistons would be on the leading egde of the pad instead of the large ones and would make the pad wear even. all i need now is someone with a porsche

[Corey]

Your calipers are the wrong way round, whoever fitted them didn't allow for the fact that your car needs a trailing caliper, whereas the Cayenne caliper on the Cayenne is a leading caliper.
You need to remove them and swap the crossover pipes over to enable them to be correct.

I imagine they have the calipers on the incorrect side also (even part number on lhs and odd part number on the rhs, which is incorrect also).

[Corey]

To swap the crossover pipes over lay both calipers in front of you and remove all 4 bleed nipples.
Now remove the crossover pipe from the lhs caliper and attach it to where the nipples once were on the rhs caliper.
Now remove the crossover tube from the rhs caliper and attach it to where the nipples were on the lhs caliper
Put the nipples back and attach the even part number caliper to the rhs and the odd part number caliper to the lhs.

Hope that helps

[jimbo1234567]

cheers corey that all makes sense to me .i never thought the brakes were as good as they should have been, jim

[mikeyquattro]

Do you know who fitted the calipers?

[jimbo1234567]

it was done by dialynx

[MarkB]

What disc's are you running with those calipers please?

[jimbo1234567]

std rs4 but the top hole on the caliper has to be elongated by about 3.5mm for the pad to fit properly on the disc, theres plenty of meat to take off the caliper.

[MarkB]

Great info, thanks. Most people turn the disc diameter down a little.

Can you see if the offset of the caliper has been changed? Also can you confirm that the disc is still the standard 360mm dia?

[MarkB]

Also, what pads are you going to use? Are the Ferodo DS2500's available?

[jimbo1234567]

ive just measured the disc and its a piddley 350mm???????????????????? if someone was going to do a brake upgrade why make the disc smaller it doesnt make sense to me pad wise ive chucked the pagid blacks that were on it and am now going to use up the pagid yellows that came with the car. before long i can see myself taking it all off in favour of a b7 setup