CRX HF-Si Rear Disc Brakes
I’ve always been a big fan of the CRX HF as a platform to build upon. It’s lightweight and lacks the extra luxury components from the Si, yet is outfitted with MPFI (multi-point fuel injection) instead of the CRX DX/STD’s DPFI (dual-point fuel injection). With a little creative swapping, the CRX HF shell can be made into a lighter, more purposeful driving machine than an Si or a DX with less work.
The stock CRX HF brakes are small, light, easy-to-maintain brakes that suit the stock 1900-lb HF perfectly. The stock drums do suffer from brake fade as soon as the car is driven moderately roughly, so an upgrade isn’t a bad idea. The problem is that the trailing arms (which are the parts that your brakes bolt to) are completely different designs.
The CRX Si rear brakes use a stronger, heavier trailing arm to mount onto. The whole assembly needs to be swapped for it to work on the CRX HF.
At the end of the day, this setup just makes maintenance simpler and decreases brake fade.
These images offer a look at the differences in the rear braking system setup between the CRX HF and Si. The first notable difference is the trailing arms, the part that supports all of the bearing housing and the area that the brakes bolt to are in fact different. The holes around the si “axle” hold the brake “plate” on, then the caliper covers that and the brake system is complete. Also, in doing this swap, be aware that the brake lines will be vastly different. I think the parking brake is shorter on the HF also.
Just for reference know that the lower control arms are also different. The parts are interchangeable (you can fit SI lca’s on the HF) but the HF lca’s don’t have the hole for the rear sway arm. If you are switching everything from an SI to HF the sway bar also wont bolt up to the body. There are holes for it, but they are only empty holes and are not threaded..
I didn’t get as many pictures as I would have liked, so if you do this swap and don’t mind sharing your pictures let me know and I’ll post up more details.