Can some one please tell me the inside mesurement of the GA rotors? I need to get started on my hubs and I need to know how much I have to take off them. So if anyone remembers what the final mesurement was for their hubs I would apriciate the help. Otherwise I will have to wate untill I get the rotors.

If it's done the same way as with Walt's 11.25" upgrade, you part the rotor section off about 5/8" back from the face of the mounting flange. In other words your cutting the cylinder section, NOT cutting through the machined sections.

As I understand it, you want a fairly close fit. With the wide variety of parts tolerances you may want to wait and match the rotors.

I looked at three motor mounts yesterday for the same app and all were noticeably different.

I am planning on making it so if i need to change the rotors again I can and the way they are made it should be fairly consistant. I dont want to have to have them mach. everytime I have to change rotors.

They looked different because rotors are NOT centered by the flange and hat. They are centered ONLY by the middle hole.

If you center by the inside of the hat you are very likely to have to screw around with them every time you need rotors in the future. Even if you get future rotors from the exact same maker.

As yet, I've seen no one propperly address this problem.

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11-Sept-01, The day the world as we knew it ended.

What about pressing a coller on to the outer part of the hub? Like what used to be used to fix a worn crank shaft at the front seal. So that it centers it the same as on the grand am?

"What about pressing a coller on... so that it centers it the same as on the grand am?" I've been thinking the same thing. Does anyone have any info about this?
Disclaimer: I know the GA brake conversion has it's problems, but I feel I need to do it to match the brakes between my 85 chassis, and the 88 craddle I'm about to put in.
Scott

[This message has been edited by AnimalGT (edited 12-21-2002).]

quote Originally posted by theogre: They looked different because rotors are NOT centered by the flange and hat. They are centered ONLY by the middle hole. If you center by the inside of the hat you are very likely to have to screw around with them every time you need rotors in the future. Even if you get future rotors from the exact same maker. As yet, I've seen no one propperly address this problem.

When the front Fiero rotors are turned down to make a hub, the idea is not to center the new rotor on this machined surface, but to clearance it so the new rotor will center on the middle hole. When doing the 11.25" brakes on the rear, a collar needs to be made because the LaBaron rotors have a larger hole in the center than the fiero rotors.

If you do it right there is no problem to be addressed, the rotors will center themselves just like the factory rotors do.

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-Brian, Toolmaker
Lincoln, NE
Silver 87' GT- Turbo Charged, Modified 2.8- 235 HP w/ 8 psi Boost, 11.25" brakes.
Maroon 87' GT- 5.7 liter TPI V8, 5-speed