Possible DIY rear disc conversion

[brushforhire]

Okay so since I can't just sit still, and leave my car alone. I want to do a rear disc swap. I want to be able to provide everyone the ability to also do this, and follow along. That being the case, I was to do everything I can using all the shelf parts. Except the caliper bracket, but I will get to that.

Being that this is a figure it out as I go kinda project, please feel free to correct me and add any thoughts you would have to this.

If this works I will make another "just the facts" type thread.

So this is what I am thinking so far:

Rear rotors - 91-95 rear Honda civic EX/si rotors. They are 4x100 bolt pattern. They are 238.8mm tall. The hat is 160.8mm tall. They are 47.6mm from the front of the hat to the back of the rotor surface. The center bore is 61.0mm. (more on this later).

or

Possibly even yaris front rotors. They are 255 mm tall. 46.4mm front hat front to rotor rear. The hub bore is already 54.1mm.

Calipers and pads - 95 Civic ex/si rears. I want to go with these because they have the e-brake built right into the caliper housing.

The mounting bracket - Okay so what I am thinking is a 1/4" plate steel bracket that would mount sandwiched the hub and bearing and the axle beam. It would end up being like a 6.35mm spacer. Gotta see how this will affect alignment of the caliper and rotor.

Possible issues I think might come up, is the fact that the rotor hat might not clear the hub mounting surface. Also depth, etc.

With the civic rotors the center bore is 61.0 mm because the civic uses a weird stepped hub ring. The rotors are 61.0 mm and the wheel bore is 56.15 mm. I have found 60.1mm to 54.1mm centering rings, I am thinking possibly a wrap of tape would bring it close enough it may not be a problem.

Also gotta modify the e-brake cable to work with the civic e-brake lever.

Process - I have a spare hub and bearing I kept when I replaced one of mine. I will make up a jig of sorts to mount it up, so I can mock up the bracket and align everything.

So those are my thoughts so far.

[NYC-SE]

Why not use the rear discs from a 3rd gen SE model? The rear axle / suspensions are the same as the 2nd generation so I'm thinking the brakes should bolt right up with limited complications. Correct me if I'm wrong.

[brushforhire]

You have to get the entire rear axles assembly. They run about $700 used without calipers, if you can even find one. I had one shipped to my work, that was supposed to be complete and loaded, and they took the calipers.

Where the hub mounts has the caliper mounting tabs right on the there on the SE, where the normal Yarii don't. I did take some tracings of the the surface, while the axle was here before I sent it back, so worst case scenario, I just make a weld on piece for our normal axles.

Edit: Here is a pic of the built in ears I am talking about.
20150806_123114.jpg

[NYC-SE]

I stand corrected.

[enviri]

i've been juggling the idea of a rear swap for others for years. I might as well share my idea.

ncp91 rear discs: 260mmx9mm non vented...It will look extremely funny with stock yaris front brakes @255mm.

ncp91 part numbers (japan, 2009):
47830-52161 (rear caliper R)
47850-52161 (rear caliper L)
47803‑52030(dust cover R)
47804‑52030(dust cover L)
47821‑12151(caliper bracket RH)
47821-12151(caliper bracket LH)
04466-52130 (pads)
04948-52040 (shims)
04948-12060 (fitting kit, pad clip)
04948‑52040 (caliper clips)

ncp131 part numbers (Canada/USA):
47830-52161 (rear caliper R)
47850-52161 (rear caliper L)
47803‑52030(dust cover R)
47804‑52030(dust cover L)
47821‑12151(caliper bracket RH)
47821-12151(caliper bracket LH)
04466‑52140/04466-52141 (pads)
04946-52080 (shims)
04948-12060 (fitting kit, pad clip)
04948‑52040 (caliper clips)

*special
04466-02310 (rear pads off 2013 ZRE172 Corolla) fits too.
(only difference there's a lack of a..metal piece stuck to 2 out of the 4 pads. Some aftermarket sports/race pads for the vitz RS in japan dont even have the metal piece)


I've gone pretty far..

a '12+ rear caliper is pretty much, similar if not same as an '09 corolla xrs/matrix xrs.
...rotors are off a '12+ yaris SE...sound familiar?
so basically, the tools needed to use toyota, is actually an idea of using the same principle as a penguin hub spacer. something about 10-13mm in thickness, with ears for the caliper. That will give the drum equipped guys a wider rear track to match the fronts. The swapper will also need to get a set of new ebrake cables (part #46420-52370, 46430-52360) since there's no more drum, and the cables are fit directly to the caliper. Brakelines may have to be changed, as it is something i have neglected to look at when i swapped. I still used aftermarket rear brake lines meant for rear drum yarii, though.

OF COURSE, i have zero clue about the engineering side, regarding torque ratings and the material needed to keep its strength while braking, and such. HELL, runstop made the adapter pretty thin, so its possible!



as for using brakes off another toyota, i have made notes a few years ago, but since disappeared, so going off memory...

I recalled researching scion TC2, and seeing their caliper mounts in the rear are off of the disc dust cover, not a beam. It also uses a drum setup for an ebrake.
EDIT: TC2 rear brake epc pics



I also did research with using a mr2 spyder rear setup or a celica last gen...but that research paper is looong gone.

[ilikerice]

This is very interesting to me right now. Especially the diagram you posted enviri.
I am definitely following this one. Not sure on how the civic setup will go, but interesting none the less.

[brushforhire]

Okay, so the rear calipers on a Miata 94-97, 99-05, seem like they would be a good choice, the brake cable attachment looks like it would be an easy fit. I can come up with a bracket to even mount the cable on, using the little silver mount.

I am thinking yaris, or older corolla front rotors. They are about 255mm and the same bolt pattern of course. Will probably have to grind down the rear hub a little. I think the hat on the rotors will just not fit.

caliper.jpg

[enviri]

Here's rotor sizes for miatas. Miatas have an advantage with sharing the same bolt pattern+center hub size...

NB (1999-2005)
Front disc Sport brakes = 270 mm
Rear disc Sport brakes = 276 mm

Front disc Non Sport brakes = 255 mm
Rear disc Non Sport brakes = 251 mm

NA 1.8 (1994-1997)
Front disc brakes = 255 mm
Rear disc brakes = 251 mm

NA 1.6 (1990-1993)
Front disc brakes = 235 mm
Rear disc brakes = 231 mm

[brushforhire]

I saw that. The only thing is that the inner measurement of he rotors is smaller. So i was hoping to find a toyota rotor that had a bigger inner to clear the rear hub. The hub face it about 5 1/4", I believe when I used my digital caliper it was about 135mm. I want to see if I can find a rotor to clear that, while keeping it no more than 255mm tall. Otherwise I will have to grind a little off the hubs. I don't mind, but I really want to find a setup that will be as easy as possible for anyone to do.

[CrankyOldMan]

As for the TC1, the calipers may be usable, but the hubs are definitely not. There's a tremendous amount of material that is not shown for simplicity of the illustration.

[enviri]

well for simplicity then i would say a hub spacer adapter will be the most straightforward...so far. It's made for the rear hubs that already exist in yarii.

[brushforhire]

Tomorrow I will compare the wooden mock-up of our hub mounting to some other toyota rear hubs and see how the holes line up.

[brushforhire]

Okay, so I did some more digging. I think I am gonna pursue the camry rear option. The camry rear hub holes a little off, but not by much. I should be able to ream the holes and get it to mount up.

The wider holes on the yaris are 83.7 mm dead center, and the camry is 90 mm. The closer mounting holes are 70.5 on the yaris, and 66 mm on the camry. So really no too much to ream out.

I believe the hole sets are the same distance apart on both hubs.

The rear of the hub, where the sensor cup would be, is 74mm on each.

Edit: I just ordered both rear 99 Solara knuckle assemblies from one my local yards. Will post pics when I can everything broke down.

Hub specs-
Yaris:
YARIS HUB BEARING SPECS2.jpg

Camry/Solara/Avalon/others:
camry hub.JPG

Newer camry hub with sensor on back:
07 camry hub.jpg

[fnkngrv]

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[brushforhire]

Got my rear hubs today!
Tear down shortly.

Quick pic:
20160602_151634.jpg

[brushforhire]

Okay so I did a quick tear down of one side, and the center hole on the 02 and older vehicles is really small. I will try and get knuckles from 05 or newer camry and that should have the 74mm hole to line up my hub. It would make the hole drilling much easier.

Also, I just about totalled my car this morning, so it kinda puts this project back. I am gonna get it towed to my house and see if I can fix it up. If not road worthy, at least make it a track car.

[MedMantle]

Oh no, what happened yo'?? Glad you're okay though! :O

[brushforhire]

Easy answer is I hydro planed. Glad I'm okay also. And that I didn't hurt anyone else in the accident. Live and learn, I suppose.