Machining a Solid Drum-in-Hat Rotor Down into a Rotor Hat

[CTX-SLPR]

Howdy,

Another generally crazy idea born out of my desire to integrate a Q45 IRS into my '64 Riviera. There is a limited direct upgrade path with putting later Q45 vented rotors under 300ZX calipers and keeping the parking brake but that's the end of the line. The stock rotors are solids and the idea hit me to machine them down so they are just rotor hats to keep the drum in hat parking brake then put Wilwood or someone's bolt on rotors on to the outside to get a rotor diameter and thickness that is more balanced with the possibilities of the C7 front hubs and custom uprights. Obviously there's the weight penalty of having a cast iron hub but I do value that parking brake enough to put up with that as this is more of a 8.5/10ths car vs. a 10/10ths car.

Thanks

[Vimes]

https://www.speedwaymotors.com/Ford-9-Inch-Pinion-Mounted-Emergency-Brake-Kit-1310-Series-Yoke,44784.html

Why not put an emergency brake on the pinion? It's true that an emergency brake at the tire is best, but this would be better than cutting up parts into adapters.

Does the Q45 not have an emergency brake already? 4 wheel disk setups usually have either a little tiny drum brake integrated into the hub, or a mechanical lever built into the caliper. Drum to disk conversions often used 1980s Cadillac rear calipers for the integrated lever operated emergency brake.

Since you mentioned the C7 Corvette front brakes, here's a pic of their rear brakes that shows the little drum brake that fits inside the rotor.
https://static1.pt-content.com/images/pt/2024/11/c7rearpng800x450-1.png

This one is the mid 80s Caddy El Dorado rear caliper. The spring assembly is the lever for the emergency brake. This one will use your Buick's existing emergency brake cabling, although you may have to fiddle with cable lengths, or use an 85 El Dorado rear cable assembly for the wheel side of the cable. Underneath there is a single cable from the pedal that hits a bracket that lets the one cable pull both cables for the wheel side.
https://static1.pt-content.com/images/pt/2024/11/91031046_L1600_d46d176334624eb0b814c8a4c-1.jpg

[CTX-SLPR]

The little drum brake inside the rotor is what I mean by drum-in-hat which is what the Q45 already has, this would just be turning the solid (i.e. the disc is solid without the ventilated webbing between the friction surfaces) rotor into an adapter to work like ones of these:
215364
To mount this
215362

I really don't like those Eldorado style calipers, I could do the math to see if they are a good balance fit for some of the front brakes I'm considering but I'd rather go with a set of VAG Brembo's for 4 piston fixed rears as I'm also considering the fronts since the complete upright will be fabricated I can make a mount for anything.
215363

[Vimes]

OK, I misinterpreted what you were going for then. My bad.

You might look at the 2010ish Mustang rear rotors. Baer Eradispeed sells them as a 2 piece with an aluminum hat and they say the emergency brake functions normally, and it has the same 5x4.5 inch lug pattern. You'd want to compare an Infiniti rotor to a Mustang rotor in person to see if they'd fit though.

[CTX-SLPR]

Looking at Centric, the only Mustang parking brake shoes I can find are 15+ and are listed as 9.0in OD. The entire housing on the Q45 is 7.5in OD so definitely not going to fit. However the Eradispeed rotor discs are another option to throw in along with Wilwood and Coleman Racing.