October 1, 2014

CRX HF-Si Rear Disc Brakes

Posted on March 4, 2010 by in In the Garage, News and Events

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.

HF Rear Brakes

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.

Si Rear Brakes

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.

Installation

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.

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7 Responses to “CRX HF-Si Rear Disc Brakes”

  1. UrbanVibe 6 April 2010 at 6:26 pm #

    Awsome, i just finished a b16a swap into a 1989 crx hf, only thing is i would like to stop. I have been looking into several ways of doing a rear disk conversion. If you have any more details / pictures or a parts list i would much appreciate it. The wheels i have are 14″ alloys, im not sure if that would cause a problem. Thanks!!

  2. Jesse 6 April 2010 at 8:26 pm #

    You shouldn't have any issues with the 14″ alloy wheels, unless they protrude really far toward the interior of the car.I don't have much regarding the rear brakes, mostly because I'm of the opinion that rear discs are a bit of a waste on these cars, I'd focus on the wheels that do all the stopping anyway: the fronts. The rears are a ton of work, and unless you're doing extremely heavy track racing, drums are perfectly suited to the rear of a CRX.

  3. UrbanVibe 7 April 2010 at 4:00 am #

    Ok awesome, thanks for the good advice, just today i finished putting the last touches to my b16a1 swap, had to replace the throttle body gasket and tps sensor. As for looking at the front end and brakes, would you suggest a wider tyre, sticky pads with drilled / slotted rotors and perhaps tower brace? I thank you for all your help and really like your write up! Thanks once again!

  4. Jesse 7 April 2010 at 12:46 pm #

    For brakes, I'm a big fan of swapping to DA Integra brakes (which you most likely did when you swapped the b16a1 in). Slotted/drilled rotors aren't an improvement on the street, but a better brake pad and braided stainless steel lines will make a MASSIVE difference.As far as tires go, I'll offer the same suggestion to you that I offer to everyone: Get the widest tires you can make overfenders for. For the Civic/CRX, that would be 949racing's 6ul line of wheels, designed for the Miata/MX-5. They're lightweight, 9″ wide beasts that will really help you stick to the ground. You'll have fender clearance issues, so I really recommend fabricating some overfenders while you're at it. I've always been partial to ZG-style overfenders, personally.

  5. UrbanVibe 7 April 2010 at 3:36 pm #

    The axles and front brakes had already been put on the car, the guy who had her before me was a bit of a ricer and spent his money destroying the hood ( another project) and ran out of money for the b16, so bought the shell and did the rest my self. Is there a way to tell what knuckles im running? im pretty sure the axles are integra's. As for the wheels now they are simply beautiful. I saw you mention them in one of your crx posts, very slick! I've written the pads and braided lines down on my list for the next few weeks. With the over fenders, do you know where i can find a “how to” as this is all new to me and have never done any “real” body work. I really appreciate your time, as many people in forums do not provide the detail and care in which you do (added with common sense).

  6. Jesse 7 April 2010 at 6:33 pm #

    That's part of the reason I created this site. Forums tend to lack a whole lot, when it comes to cohesive information. It's too easy for members to build up an off-topic post count and pretend they know everything under the sun when they're really only as smart as you or I. I think I'm going to write up a post about flaring fenders, different methods you can use to do it, and most importantly WHY to do it. Give me a bit and I'll get that published.

  7. UrbanVibe 7 April 2010 at 6:37 pm #

    Excellent, thank you once again! Im trying to find out if i can source a set of those rims, is there a way i can find out what calipers i have with out removing the pads and disk?


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