Xman

A concern many have about the conversion to 05 OEM brakes is the 04 caliper brackets are secured with 12mm bolts and the 05 with 14mm bolts. There is no safety concern about using the 12mm bolts with the 05 brake system. All the aftermarket brake upgrades use 12mm bolts with their system, some with even more braking power than the 05 OEM braking system. Some GTO owners have purchased the 05 knuckles with their 05 brakes as a package deal from the salvage yard and swapped these assemblies to avoid adding the shim to the 12mm bolts. If you go down this route, you most likely will need to get a wheel alignment.

I wanted to see if I could find a simple way to shim out the additional .040 (radius) difference between the 12mm 04 bolts and the 14mm 05 bolts. The 05 bracket bolt holes are .555 inches in diameter, which is only .055 over ½ an inch. I called around to some pipe fitting shops and found there was stainless steel tubing used in commercial air conditioning that had a ½ inch outside diameter and a .035 wall thickness – close enough to .555 and .040 for me. It only came in 20-foot lengths but the local shop was friendly enough to cut me off a 6-inch piece at no charge. My plan was to use this tubing to fab and press a sleeve over the 12mm bolts.

The tools you need for this task are a hacksaw, hammer, a punch that is more than a ½-inch in diameter, and a vice. You can get them all at Sears. If you don't want to get a vice, ask to borrow a friend’s. I have had a vice for years and don't know what I'd do with out it. Your other option is to go to a machine shop and ask them to do it for you. I had one as a back-up if my plan did not succeed.

The first thing you need to do is flair the tubing slightly so you will be able to start it over each bolt since the tubing’s inside diameter is smaller than the bolt’s. I did this using a large punch. I would drive it into the tubing, knock the punch back out, and then cut off a little more than a half inch off the tubing and deburr it. The length is not critical as long as the sleeve is not cut longer than the bracket is thick. I repeated this 3 more times. The sleeves pressed on very easily using a vice. I’m not even sure I needed to put lube them. I would recommend finding a way to flair both ends of the sleeve so you have a wider base to lip the tubular sleeve, making it easier to tap the sleeve up the threads of the bolt. I had a special metal base that just happened to have a matching hole in to that would let the 12mm bolt go in but not the sleeve. It would have been easy enough to complete this last step of knocking the sleeve up the shaft of the bolt by using the two sides of the vice set just wide enough to let the bolt pass but not the sleeve. How far you knock the sleeve up is not critical. Once you get some thread showing, the sleeve will travel up the bolt shaft as you tighten the bolt back into the knuckle. Remember to use some blue Loctite on the threads before you re-install the bolts back onto the knuckle.

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05 Brakes w/ C5Pads, K&N CAI, TBCoolantByPass, -CAGS, , +Outlets, DeadPedal, UnSpoiled, GasCapHook, PedalsRightSideUp, HitchToGo,