I'm in the planning stages of a brake upgrade for my dad's 86 or 87 (can't remember) C4. From what I've read on here we're looking at the j55 or C5/C6 front calipers, retain stock rears, change a spring in the master(?), and of course wheels big enough to fit the bigger rotors/calipers.




Right out of the gate I'm leaning towards the C6 brakes (depending) because I've got CTSV 6 piston calipers on the front of my 05 GTO, which left a set of (apparently?) C6 calipers available. The abutment brackets are different however, the spacing looks the same but the bolt holes are in different spots, so to use the available adapter brackets I'd have to acquire some C6 brackets, or make new adapter brackets to fit the GTO abutment brackets. I'm leaning towards getting the C6 abutment brackets. If that will work, what rotors do I use?

I say "depending" because I wasn't able to find solid information on whether the C6 calipers are literally identical to the 05-06 GTO calipers. If they're not then I may start looking into finding some j55 stuff.

As for wheels, my dad really doesn't like aftermarket. So I would have to retain a stock C4 appearance as far as that goes. From my research here it seemed like the sawblade 17s would fit both the j55s and C5/C6 calipers using a spacer. The GTO had 17s so hopefully 17s with the correct back spacing will work for this too.

Oh and as far as a spare, when I installed the CTSV brakes on my car the factory 17" spare also went up for grabs so I think I've got that covered too.

I think I remembered everything, what do you guys think?

 

Btw I will definitely be using some Russell or Goodridge braided stainless lines, I just didn't mention it because that's pretty straight forward.

 

Bump,

I think I've confirmed that my leftover 05 GTO calipers are in fact identical to C6 non Z06 calipers so It's looking like I'd still need to get the abutment brackets to work with the adapter brackets. I assume I just use stock C6 rotors? And can anyone confirm that 17" sawblades will fit on this setup with spacers? I could maybe convince my dad to go with some C5 or later wheels but I think the sawblades would look best anyway. Thanks

 

Well never mind, he didn't like any of the other factory wheels offered on the C4 so that's kind of a deal breaker. I told him we could just put some Russell SS hoses on it, flush all new fluid and get new pads and rotors front and back and that would probably be a decent upgrade from where it's at now. It would have been fun but it is what it is, I can't live vicariously through my dad lol