89 CRX Si – rear disc brake conversion

[kmoallem]

Hello,

I’ve managed to score a set of rear disc brakes from a 91 CRX Si (complete trailing arms with all lines/cables/rotors/calipers). And, I would like to throw this into my 89 CRX Si.

I just need a little reassurance here, do I also need to change my master cylinder, brake booster and proportioning valve? Or will I be ok with just swapping the trailing arms?

I’ve already done a bit of research on the web regarding this … but I didn’t find much information about the master cylinder/booster/proportioning valve.

Thanks in advance

 

[kmoallem]

Ok a bit more information ... my current MC is 13/16 and the Prop. Valve is 1725.
Do I need to change these for a PROPER rear disk
brake conversion?

Thanx.

 

[buckn8ked]

I have read you will need a "4040" prop valve and may wanna use the MC from a 90-93 teggy

 

[kmoallem]

Thanks for the reply. I have a chance to pickup a 7/8” MC and a 3540 Prop Valve. The seller says that it is the correct setup for a CRX rear disc conversion. The parts came out of a 91 Integra (the MC at least). I would like to keep this conversion as close as possible to a CRX with stock rear discs …. Does any body know the stock MC and prop valve specs for a CRX with rear discs?

Cheers

 

[buckn8ked]

I think theCRX SI has rear disks ... I am not sure but i think so

 

[eg6sir]

the 91 had discs in the rear

 

[kmoallem]

Yes, the 91 SI had rear discs ... I have an 89 SI with drums and the trailing arms from a 91 (with discs) that I would like to throw into my car. So my questions are:

1) Does my current master cylinder (13/16") and proportioning valve (1725) need to be replaced for a proper conversion?

2) What are the stock specifications for the MC and Prop valve for a 91 CRX SI?

cheers

 

[Periculum]

You shouldnt HAVE to replace the booster or master cylinder for the brake conversion, but it would be a great idea. The proportioning valve would be a must though else you wont get near the full power of the rear brakes. right now i have a teg MC and brake booster on my HF fronts (until i get the rear disks) and its an outstanding difference alone (perception more than performance difference, you just have to press the pedal less) I would suggest changing out those as well if you can, all at the same time would be easier than separating the tasks.

EDIT: I keep forgetting the SI had disks too, Youll probably be able to just use the MC out of that. If you change to a teg MC youll HAVE to change the booster as well because the MC mount on a teg is exactly opposite of that on the civics. unless you know how to keep brake fluid in while its upside down.

 

[kmoallem]

Thanks for all the suggestions! This is not an urgent upgrade … so I’ll take my time and try to find the integra MC/brake booster and a 4040 prop valve. I’ll pick up new front & rear rotors / pads and change over to steel brake lines too!