Intro:
After the last Celica meet, I was able to snag a few parts that would help me develop out an affordable big brake kit for the 7th Gen Celica. Tom let me borrow a TRD TC2 (Second Gen Scion TC TRD Big Brake Kit) caliper, a DBA Subaru Rotor (“DBA rotor” going forward in this article), as well as a Cadillac ATS Brembo caliper. The intent of this project is to take as many OEM parts as possible and adapt them together using custom bracketry, lines, and parts. Here is the detailed goal list:
- Use OEM Rotors
- Use OEM Calipers, Brake Pads, and Hardware
- Find the Most Affordable and Easily Accessible Parts
- Design Custom Parts to Meet or Exceed OEM Standards
- Keep Custom Parts Minimal
Combinations (On Hand):
My first goal was to grab the parts I had and start mocking them up to see how they fit together. Below, I’ll try to go through the combinations I had on hand to give you an idea of what I was working with.
DBA Rotor / TRD TC2 Caliper:
This was an easy go/no go check. When you attempt to put the TC2 caliper on the DBA Rotor, the DBA rotor doesn’t fit due to its thickness. I couldn’t find specifications on the TC2 Rotor, but they must not have much thickness to them at all. By the way, this check was done WITHOUT the brake pads loaded in the caliper, which may add additional thickness to the caliper slot (didn’t even look). For all intents and purposes, the TC2 caliper might not be worth the work to get it to fit due to the thin rotor required.
DBA Rotor / ATS Caliper:
This combination was the one that I originally thought would work. There is a website that already does swaps like these: CTSV Brake Swap. In fact, they even have products for Subarus and FRS/BRZ/86s, so the feasibility of this idea should be good! Well, after doing some mockup, this is what I’ve found:
1. This is the closest you can get the caliper and rotor together, by clocking the caliper past the hub mounting ears. 
2. As you can see, this hangs the caliper too far out from the rotor 
3. This is the more preferred position, but even after milling about 1/8″ off the caliper ears, is no where close 
4. This is how much the pad overhangs on the non-clocked mounting position 
5. Without the hub in the way, the caliper and rotor fit together really well 
6. Again, without the hub, you can see there is room to move the caliper out to match the rotor. However, this caliper actually requires a 32mm thick rotor
As you can see from the slideshow, the DBA rotor/ATS Caliper won’t work well together on the Celica Hub. When I was mocking everything up, it became apparent to me that to get something like this to work, I’d need a larger diameter rotor to bring the caliper out and give clearance to the OEM mounting ears.
Research/New Parts:
First thing’s first, I need to find all the dimensions for the DBA rotors that I have:
I was then able to take a quick measurement to see approximately how much more space the ears needed before there was some clearance and it seemed like ~1″ (25mm) would work. Then, I went to a website tool that allows you to search all rotors based on size dimensions (Search Brake Rotors by Size | AllRotors.com) and added the two major constraints for this project: 350mm rotor diameter and 32mm thickness.
Now, we have a small list of OEM rotors to choose from. If you look through them, none of them are 5×100 bolt pattern (this requires additional research). However, if we remember our DBA Rotor has a height of 53mm (which has a few millimeters of clearance to the ball joint), we can see that basically any of these rotors will work. The rotors we have to choose from on this list are Mitsubishi Evo, Mercedes (multiple) and Dodge Durango/Jeep Cherokees. Knowing how the aftermarket works, the Evo rotors and the Mercedes rotors are going to be twice as expensive as the Durango/Cherokee rotors. Let’s dive into this more.
Durango Rotors:
To make it simple, we need to make sure that the hub bore is larger than the Celica and that the bolt pattern is larger, as well. The Durango rotors are 5×127 and the bore is 71.6mm. The Celica has a bolt pattern of 5×100 and a bore of 54.1mm. That means, in order to make these work, I’ll need to machine the 5×100 pattern into the rotor and create a 54.1mm ID / 71.6mm OD ring that will center the rotor on the hub flange.
The best part about the Durango rotors is they were used for 9 years on two different models, meaning that the supply will be readily available, and they should remain affordable in the long run. I was able to get a pair of them for $120, yes, a PAIR.
Outro:
This post talked about borrowing some parts in order to create a DIY Big Brake Kit for the Celica. In the next post, I’ll discuss the machining operations I needed to do to fit these parts together as well as additional challenges as I move this product through R&D.