6 replies to this topic

[armegedon667]

Ok, so after a long absence I have acquired a very nice red 86 Si once again. This forum is such a huge resource I thought I would add some items as I make some changes to my new CRX.

I recently came across some very nice rear drums with backing plates and front calipers from a '00 Insight. As we know these drums are aluminum. I verified weights on my handy digital scale and the Insight drum weighs 4lb 11oz while the CRX drum weighs in at 7lbs 1 oz. The brake assemblies were in very nice condition. I had pulled my drums and found 2 leaky wheel cylinders so I was due for a full rebuild. Having the all-Honda parts Insight drums in my hands I thought it made the most sense to do a full insight rear brake conversion.

The first issue is that the backing plate bolt pattern and center hole diameter are dramatically different.

https://drive.google...?usp=drive_link

To utilize the Insight backing plates would realistically mean welding in a new adapter plate given the mounting hole locations. Ok, I can do it but it would be very time consuming. Using the CRX backing plates is possible but you must remove the inner water deflection ring and use the CRX shoe retention pins. Given I will likely never have this car out in inclement weather I decided to utilize the CRX backing plates and remove the inner ring.

https://drive.google...?usp=drive_link
https://drive.google...?usp=drive_link

Ok, so far so good, the drums will fit, however I wanted to use the insight shoes, cylinders, etc. Upon examination the Insight uses an 11/16" wheel cylinder while the CRX uses 3/4. The width of the two units is slightly different with the Insight unit being a bit narrower.

https://drive.google...?usp=drive_link

If you attempt to use the CRX wheel cylinder the Insight shoes cannot be adjusted back enough to clear the drum. Therefore: to use Insight shoes you must use Insight wheel cylinders. These cylinders are mounted in the same location but use bolts not studs, and the position of these is 3/8" higher center to center than the existing holes. Luckily, with the hole being 1/4" you can drill new holes with plenty of material remaining and mount the Insight wheel cylinder into the CRX backing plate.

I thought was looking good at that point but soon realized that the lower shoe stop is also correspondingly narrower on the Insight.

https://drive.google...?usp=drive_link

This must also be swapped onto the CRX backing plate.

https://drive.google...?usp=drive_link

Interestingly, on the CRX the e-brake bracket sits below the stop and serves as a surface that the shoes ride on. On the Insight this bracket sits on top of the stop and serves as both and e-brake bracket and the lip so the shoes cannot exit their channel. Both stops are riveted in place. One must drill out the rivets and carefully preserve the parts from each backing plate. To assemble the new backing plate stop you will utilize the CRX e-brake bracket, the Insight stop, and the Insight e-brake bracket with the e-brake channel cut off to serve as the upper lip. You will need to source 2 bolts and nuts to hold this assembly in place unless you have a giant rivet tool.

https://drive.google...?usp=drive_link

Once this work is complete you will have Insight rear brakes on you CRX. Interestingly, this smaller wheel cylinder should compensate for the larger piston volume on the front calipers to give close to a proper braking feel on the stock MC. Proportioning is another matter.

Next up will be Insight aluminum front calipers on adapters with Mirage 9.9" rotors. Should be fun. I will document that as well.

[CSPCRX]

Nice right up and good luck on the project

[armegedon667]

Thanks.

I can now verify that insight calipers weigh in at 4lbs 7oz, the stockers are 5lbs 8oz. Piston diameter is 51mm for the insight calipers and 44mm for the stockers. Once bled and adjusted the braking pedal travel and feel is very similar to stock.

[CSPCRX]

With a larger piston bore you may see less actual pressure at the pad for the same amount of pedal travel.  If your not tracking the car this may not matter for you.

[armegedon667]

I think in this case it seems to be offset at least somewhat due to the smaller Insight drum wheel cylinders. They are 11/16 vs 3/4 on the CRX units. I just checked and the CRX HF's all used 3/4 wheel cylinders as well. I wonder why Honda ran smaller wheel cylinders on the Insight...

[CSPCRX]

Okay I miss understood what you were saying so yes should be okay

[greasemonkeyreborne 5x1g's]

Armegedon,   Thnx for posting your findings!,  totally agree. Great resource here for future ref and comments