Alternative rear disc conversion?

[Compeer]

Originally Posted by Neinris

I just realized I could run just one long rubber hose per side to the rear calipers instead of having multiple couplings. I’ll buy the Corolla rear brake lines and see if they’re long enough.

Just go to a brake shop and have hardlines made at that point and move the tabs at the same time, you would need to make propper mounts to hold the hose correctly may as well just get little hardlines made and move it, but personally I just went back to stock holes. Need to put my tein flex z back on soon, I want some 5mm spacers.

[Neinris]

Originally Posted by Compeer

Just go to a brake shop and have hardlines made at that point and move the tabs at the same time, you would need to make propper mounts to hold the hose correctly may as well just get little hardlines made and move it, but personally I just went back to stock holes. Need to put my tein flex z back on soon, I want some 5mm spacers.

I actually have all the hardware I need to do the disc brake swap, minus the brackets for the hose lines. I wanted a different approach to reduce the coupling from hardline to rubber, to hard line again, then rubber to the caliper.

[sh0rtlife]

ive got a shop local that i get custom braided lines from for CHEEP..so that would be my fix lol

[Neinris]

Originally Posted by sh0rtlife

ive got a shop local that i get custom braided lines from for CHEEP..so that would be my fix lol

My suggestion to you is to not go steel braided line in the rear, but the front, to soften the braking power in the rear since you’re hell bent on keeping your 14s.

Most likely, I’ll be installing my conversion next weekend. I think I know what I’m going to do with what I have.

[sh0rtlife]

Originally Posted by Neinris

My suggestion to you is to not go steel braided line in the rear, but the front, to soften the braking power in the rear since you’re hell bent on keeping your 14s.

Most likely, I’ll be installing my conversion next weekend. I think I know what I’m going to do with what I have.

when i flushed everything and put the drilled n slotted up front and new drums in the rear i put all braided lines on it because something was feeling "off"..turned out one of the lines was deteriorating on the inside..which is more common than you think....so ive allready got the braids

i think at this point im more curious as to how the hand brake cables and your adapter go together

[Neinris]

Originally Posted by sh0rtlife

when i flushed everything and put the drilled n slotted up front and new drums in the rear i put all braided lines on it because something was feeling "off"..turned out one of the lines was deteriorating on the inside..which is more common than you think....so ive allready got the braids

i think at this point im more curious as to how the hand brake cables and your adapter go together

I hope this pic helps. I didn’t put the cable through the hole yet, because it’d be a bit of a challenge to remove. Now what is the concern again? Worried the cables will be too short? The mechanism pulls from the top, but it’s clocked closer to the parking brake cables. So I think they’d be just right.
Get the calipers meant for the Yaris, and the cable length will not be of any concern.

[sh0rtlife]

good thinking on the dual clocking

brz twin pots on such a lil gokart would be down right insanity....you would have to be running atleast a 245 to be able to even use them!!!!

[Neinris]

The twin pots caliper are for the front though right?

The BRZ's front rotors are 326mm in diamenter!!! But they're 5X100 PCD.

The 2nd GEN Scion xB's front rotors are only 275mm in diameter compare to the BRZ/FRS, and they're 5x114.3 PCD. I wonder how far the BRZ's front calipers will stick out when mounted on the Yaris' steering knuckles? I hope not too far out for 275mm rotors...

You'd definitely would need to get at least 16in wheels for them to fit.

I'll keep this in the back of my mind...

[sh0rtlife]

its not about sticking out its about bolting them onto the correct mount to bring them down to the 275 rotor

[Neinris]

Originally Posted by sh0rtlife

its not about sticking out its about bolting them onto the correct mount to bring them down to the 275 rotor

I'm getting my threads mixed up...

Well, that's what I kind of mean or need to know. How far will the caliper move out when it's mounted on a Yaris' steering knuckle? Will it be the same as the BRZ where you can house a 326mm rotor or will it be in like the Yaris SE/Corolla/xD? Or is there a different caliper carrier that it can be Frankenstein with and dial it for a 275mm rotor if you want to do a 5X114.3 PCD. Could I just make an adaptor plate and move out the xD calipers that I have to house 275mm rotors? But then the pads won't follow the same contour as the rotor. Would that really matter?

I've thought about using a 2nd GEN xBs steering knuckle, but looking at the holes, I don't think it'll mount to the Yaris' strut. You could probably use the xBs strut, but use the Yaris' top hat?

For the rear rotors, since it's solid, I could just mill down the xBs 279mm rotors down to 259mm, and still use the stock Yaris SE calipers. I don't think I can do that to the front rotors since they're finned. Or use the 279mm rotors, but will definitely need to install a proportioning valve, since the rear rotors are bigger.

[Neinris]

I made the brackets out of aluminum angle, I couldn’t find anything else that’s 1/16in thick. Well at least I know they won’t corrode, and they’re strong enough that I can’t fold them by hand. I cheaped out and made my own retaining clips too…
Once I position them on the axle frame, I’ll drill holes on the base and rivet them down. Yeah I know not welded, but it should still work.
I also made two extra ones with smaller hole, incase the hoses I’m relocating are differently designed than this hose. The hose in the pic is one that will connect to the caliper.
I don’t know why the first pic is upside down…

[Compeer]

Originally Posted by Neinris

I made the brackets out of aluminum angle, I couldn’t find anything else that’s 1/16in thick. Well at least I know they won’t corrode, and they’re strong enough that I can’t fold them by hand. I cheaped out and made my own retaining clips too…
Once I position them on the axle frame, I’ll drill holes on the base and rivet them down. Yeah I know not welded, but it should still work.
I also made two extra ones with smaller hole, incase the hoses I’m relocating are differently designed than this hose. The hose in the pic is one that will connect to the caliper.
I don’t know why the first pic is upside down…

The clips atleast need to be the original hardened spring steel, Alu cannot work as a spring.

[sh0rtlife]

Originally Posted by Compeer

The clips atleast need to be the original hardened spring steel, Alu cannot work as a spring.

exactly true, the aluminum is just going to let it go under pressure, or bend back n forth till it breaks off...it may not be "quick" but eventual inevitability

if you want "new" look for street rod hose mounts, if you want quick n dirty either cut some off a TRUCK/SUV...or even a car..tho on a car its hard to get enough materiel left to mount them

you can even look at clutch hose mounts, it only needs to fit the hose not the car, alot of the street rod ones are either studded for mounting or threaded for mounting so its easier to slap em in and be done

also aluminum on aluminum can and WILL corrode in fairly short order

[Neinris]

I forgot to put into account that the drum brake back plates has some thickness to them, about 2mm. With the 1/4in plates (6.35mm), I’ve only added 4.35mm to each sides. The front are still .65mm wider at each side, 1.3mm wider total.
A7CAC2E1-A66E-46F2-BBB6-EC1A01BC0EB1.jpeg
The back of the hub dowel?, I don’t know what to call it, protrudes about 8.15mm, about .5mm is taken by the splash guard, so there’s still at least 1.3mm inserted in the axle beam. So the weight are not all on the bolts.
67C3E5E3-991B-49DC-9B20-E4A723ED7F7B.jpeg

[remcafee]

glad you finally got your rear discs done, never adjust and clean stupid drums ever again!

[Neinris]

Originally Posted by remcafee

glad you finally got your rear discs done, never adjust and clean stupid drums ever again!

Thanks remcafee… you were the first to reply to my thread 2 years ago almost to the day. I appreciate your inputs and assistance, along with everyone else.

Most have mentioned that these tiny cars don’t need rear disc brakes. That might be true, but it’d be so much more convenient to replace the brake pads now, and like you mentioned, no more adjusting and cleaning the stupid drums ever again!

The other factors I want to share are the fact that my fuel consumption has improved, not because the car is lighter now, but the fact that my drum brakes apparently overtightened themselves, which was causing some drag. Also, I’m no longer staying in 4th gear anticipating having to stop in my city driving.
I do have to get used to how quickly I stop now, before I was afraid of hitting the car in front of me, now I’m afraid of cars rear ending me…
I’ve mentioned that I don’t have ABS, I've tested if my rear wheels would lock up first, but I couldn’t get the wheels to lock up at all, granted I was only going 45mph. I’ll try to test again some other time.

The other “alternative” that I want to present are the fact that the Prius and 2nd Gen Scion xB (xB2) has the same mounting holes bolt pattern like the Yaris. If I’m a betting man, the rear axle beam from those vehicles will fit in the Yaris. So they present as an alternate to the Yaris SE rear axle beam.
My new neighbor has an xB2, I’ll see if he’s willing that I’d take measurements and take pics. I’ll post pics here if or when I get the chance.
Next project is 5X114.3 PCD conversion.

Oh, and I went ahead and painted the front calipers red. I took the brake pads off and put a bag over the rotors.

[Compeer]

Originally Posted by Neinris

Thanks remcafee… you were the first to reply to my thread 2 years ago almost to the day. I appreciate your inputs and assistance, along with everyone else.

Most have mentioned that these tiny cars don’t need rear disc brakes. That might be true, but it’d be so much more convenient to replace the brake pads now, and like you mentioned, no more adjusting and cleaning the stupid drums ever again!

The other factors I want to share are the fact that my fuel consumption has improved, not because the car is lighter now, but the fact that my drum brakes apparently overtightened themselves, which was causing some drag. Also, I’m no longer staying in 4th gear anticipating having to stop in my city driving.
I do have to get used to how quickly I stop now, before I was afraid of hitting the car in front of me, now I’m afraid of cars rear ending me…
I’ve mentioned that I don’t have ABS, I've tested if my rear wheels would lock up first, but I couldn’t get the wheels to lock up at all, granted I was only going 45mph. I’ll try to test again some other time.

The other “alternative” that I want to present are the fact that the Prius and 2nd Gen Scion xB (xB2) has the same mounting holes bolt pattern like the Yaris. If I’m a betting man, the rear axle beam from those vehicles will fit in the Yaris. So they present as an alternate to the Yaris SE rear axle beam.
My new neighbor has an xB2, I’ll see if he’s willing that I’d take measurements and take pics. I’ll post pics here if or when I get the chance.
Next project is 5X114.3 PCD conversion.

Oh, and I went ahead and painted the front calipers red. I took the brake pads off and put a bag over the rotors.

Looks good, Ive been lazy and haven't painted mine yet...not sure what colour Id do other than red.

[Neinris]

I was hoping to drop this comment yesterday to commemorate the two year start date of this project, but I got too busy.

Anyway, I know there's other threads out there that discusses what parts are required, etc., here's my version of what's required:

Rear disc conversion
Parts required:
Yaris SE parking brake cables (right) 4643052360 (left) 4642052370 [will require swapping hangers if not the same GEN Yaris]
Yaris SE rear axle beam 4210152160 or adaptor plates made
Yaris SE hard brake lines (right) 4732352110 (left) 4732452100
Brake hose retaining clips (2) 9046808035
Yaris SE brake hoses (2) 9094702E11
Brake dust shield (right) 4780352030 (left) 4780452030 [optional]
Yaris SE rear rotors (2) 4243152080
Toyota hub bearing mounting bolts (8) 90119A0350 [longer w/ washer (cut the washers out), not required if doing axle swap]
Yaris caliper carriers/bracket (2) 4782112151
Disc brake caliper pins (4) 4783512150
Bush dust boots (4) 4787512150
Caliper bracket mounting bolts (4) 91552C1035 [require washers if using adaptor plate vise axle swap]
Yaris Calipers (right) 4783052161 (left) 4785052161
Caliper mounting bolts (4) 90012AA102
Yaris SE rear brake pads (set) 0446652170
Yaris SE rear brake pads shim kit (set) 0494652080
Yaris SE rear brake pads anti-rattle clips (set) 0194812060
Toyota brake caliper banjo bolts (2) 90401A0001
Toyota caliper copper crush rings (4) 4738950020
Brake fluid of your choice
Note, these are all Toyota part numbers (according to parts.toyota.com), which are expensive. Aftermarket can be found for much cheaper and sometimes much complete where you don’t have to buy them piece by piece. I used a combination of RockAuto.com and EBay to get my parts. I was in no rush to get them, I did this over time when I have a little bit of money for myself, and so my pocket didn’t take too much toll.
Another option is you could go to the junkyard and pull them. If you’re looking for calipers in the junkyard, you could actually grab the 2nd GEN Scion xB’s (xB2) calipers, but use the Corolla rear caliper brackets, the xB2’s caliper brackets extends farther out to accommodate the 279mm diameter rotors, Yaris and Corolla rear rotors are only 259mm. The first pic right below shows the Corolla, xB2, and Yaris' calipers, then the Yaris's caliper over the xB2's caliper, to show that the bracket is extended out.
Corolla vs xB2 vs Yaris calipers.jpg
xB Yaris rear caliper.jpg
Also, I want to say that the Scion xB2 and Prius rear axle beam could probably be used as a replacement for the Yaris SE, but I'm not yet 100% sure at this point. I want to point out that the mounting hole bolt patterns are the same as the Yaris' rear wheel hubs.

If you’re not doing an axle swap, a couple of brackets must be made and welded on the axle beam for the rear most brake hoses that bolts to the calipers (sorry I don't have a picture of how I did this). What I did was mockup the locations by installing the hard lines first, then marked where the spots would be as close as possible to the stock locations. I believe that the brackets that I made are 1.5in (48mm) wide by 2in long (51mm), and 1/16in (1.6mm) thick with ¾in hole (19mm).
For the adaptor plates, I recommend using a ¼ inch or 6mm thick steel plates. The exact dimensions of the ones I used are 6 inch X 6 inch X ¼ inch, this is strong enough, and any thicker would make the center bore dowel not rest into the axle frame, which would make the bolts bear all the weight. In my previous post, I measured the center bore dowel at about 8.15mm. With the ¼ inch steel plate added with the thickness of the slash guard, the thickness is about 6.85mm, that leaves about 1.3mm of protrusion through the back, to rest in the axle beam's hole.
Rear Hub & Adaptor Plate.jpg

My previous calculations were wrong, when I said how much the rear track got wider, I forgot to include the splash guard, which are about .5mm thick. The original drum brake back plates were 2mm thick. So subtract that from 6.85mm, which means the rear got pushed out 4.85mm on each side, making the front still .3mm wider, not 1.3mm like I previously said. I could still be wrong, because I didn't really got to measure the splash guards. All I know is that the wheel hub's center bore dowels still has some protrusion, because they were not sliding off even without any of the bolts in yet.
Maybe when I replace the hubs to the 5X114.3 PCD, I'd hope to remember to take the measurements of the splash guards, then I'll see how much the rear track really got pushed out. Anyway that's another project...

I used the Corolla’s rear hub mounting bolts, since they are longer and I got them from when I initially was going to use the Corolla’s adaptor plate, but they will require cutting out the washers.
Corolla Hub Bolts.jpg

To make the holes and bolt pattern on the adaptor plate, I had the Corolla back plate as a template, but one out of a cardboard can easily be made, I recommend something a bit thicker material.
Start with a 74mm hole, put your wheel hub in it and drill out the mounting holes, I believe they were 12mm if I remember correctly. I bought new wheels hubs, so I used them as a template, so I didn't have to remove the ones out of my Yaris. As you drill one out, put a bolt in it's place so that the hub don't move/swivel and get a more accurate pattern. Leave the hub in place, and fit the rotor. Now mock the caliper with the bracket and mark where the it would mount on to the plate. I don't remember the bolt hole size for the caliper bracket, I think 10mm. Then transfer that to the adaptor plate and Voila!!! Or send me a PM and you can have a pair for $75 plus shipping.
I hope someone finds this useful.