rear disc brake tech

[boggerunner]

79-95 rear disc brake brackets
parts u need
81-85 solid front axle rotors
81-85 solid front axle wheel studs
79-85 calipers
longer bolts to replace studs
7 nuts
2  1/4" wheel spacers  $15 shipped
1 set of rsm rear disc brake brackets  $50 shipped

what they look like now




How they came to be.




I've been doing some research on rear disc brake setups, and the one setup i like keeps it all toyota.
I'm runing a dual diaphram booster with a 1" master cyl.  I have V6 calipers with vented rotors up front.
The rear now has 84-85 non-vented solid axle rotors and calipers.  The proportioning valve has also been removed.
first i tore down a set of 86 rear axle shafts
next i pressed out all of the wheel studs
then i ground the inside of the rotor to fit on the back side of the axle shaft
i pressed the 85 front axle studs through the rotor and rear axle shaft
press the bearing assembly back on after removing the backing plate
the studs are a bit to long, so i ordered some 1/4" wheel spacers from Big O Tires for $5 apiece
i also had to gring the back of the caliper a bit to get some nubs off
now with some pics

[boggerunner]

the bolts holding the bearing retainer are also gonna hold on the caliper bracket.
the brackets will work for ethier side also.
im just using this one for mockup. we are gonna get it into a cad program and cut out a few on a plasma table.

[Jordan7118]

NOICE!!!

Please add this to your sig so I can reference from time to time. Again, thanks for the tech!!! 

[boggerunner]

no problem, i wonder if the 1/4" plate im using will be enough for these brackets.
im going to get some grade 8 metric bolts for the axle flange/caliper mount too.
i dont want to chance it with the stock ones, im not sure what grade they are.

[Jordan7118]

no problem, i wonder if the 1/4" plate im using will be enough for these brackets.
im going to get some grade 8 metric bolts for the axle flange/caliper mount too.
i dont want to chance it with the stock ones, im not sure what grade they are.

Good idea on beefier bolts.

The caliper mounts I got made by Muchado or Techtafab on pirate are 3/8" plate if I remember correctly. I think 1/4" would be okay though. The force is around the axle, not across the plate, so I think that's thick enough.

Again, thanks for the tech!!

[4runnerchevy]

no problem, i wonder if the 1/4" plate im using will be enough for these brackets.
im going to get some grade 8 metric bolts for the axle flange/caliper mount too.
i dont want to chance it with the stock ones, im not sure what grade they are.

When I made my plates, for my chevy brakes I used 3/8 plate (cause that was the offset I was looking for).  The forces are all in shear, so everything is gonna be on the bolts, and bolt holes.  My only fear would be the plates warping over time, but only time will tell.  Looks good.   

[Wermz84]

Very nice.

I too have started researching rear disc brakes.   

my thing is though; I want to keep it all toyota, and I want the calipers to have E-brake provisions.  I just need to find what calipers will work.


keep up the good work.

[*ROKTOY*]

I can tell you not to use the caddy ones, they use a foot actuated e brake and you can't get enough leverage to operate the e brake good enough with the Toy hand brake.

[Ramrod]

techtafab makes bolt on brakets for that setup that are super clean.

Here is my all toyota rear disc setup.  Stock Taco 4piston calipers and vented rotors-


you have to plumb in an aftermarket proportioning valve and turn the power to the rear brakes way down or else they will lock up way before your fronts do anything.   I played with it for a while before I got it exactly where I wanted it.  Another thing is that since the stock rear axle setup is only semifloat there is some runout in the rotor which can cause the pedal to go soft.  This can be cured with a $19 residual pressure valve that is also sold by summit racing and easily plumbed inline

[All_Set]

Questions:

What year is your truck?  (84-85 I assume)

What year truck did you get your dual booster off of?

Care to measure the diameter of your stock booster? 

What MC are you running?

[boggerunner]

its an 85 excab
booster from 88 v6 truck
master cyl is off an 87 supra 1" aluminum master

[Fivel]

  I can't find any info on techtafab...I would like to see what their setup cost

[Jordan7118]

Search for Muchado's writeup on pirate. He did a pretty good article on it.

[Fivel]

Search for Muchado's writeup on pirate. He did a pretty good article on it.

I read that one, it was great, but I can't find anything on where to buy these techtafab plates

[Jordan7118]

I read that one, it was great, but I can't find anything on where to buy these techtafab plates

Hmmm... PM techtafab on this board - http://www.trailkrawlers4x4.org/tkbbs/index.php

He frequents there. I bought mine from someone else who didn't end up installing them.

[Fivel]

thanks Jordan

[4runnerchevy]

my thing is though; I want to keep it all toyota, and I want the calipers to have E-brake provisions.  I just need to find what calipers will work.

My chevies are e-brake equiped although I still use my t-case brake.

[Jordan7118]

thanks Jordan

You're welcome! Glad to help!!!

[boggerunner]

i got the pass side bracket done, now i just need to get these into a cad program, then i will cut out a few sets on the fire table. anyone interested in a set of these?

[boggerunner]

they are done and on the truck, i just need to bleed them and test them out.  i need to move the caliper out an 1/8" on the next set, the disc rubbed on the inside of the caliper.  but i took care of that with a flap disc.  i will get some pics tomorrow

[82 HiLux]

im very interested to see how this turns out

[boggerunner]

got a pic of it through the rim, i painted the caliper red

[RABIDYOTA]

no worky

[boggerunner]

yeah, photo bucket wont fix it till the 31st, they suck
unless i shell out $40

[82 HiLux]

i think im going to do this.  i have wanted rear disk brakes for a long time, and it never occured to me how cheap you can do it for. 
i JUST got rid of my 82 front axle solid rotors the day before i read about this. they were in good shape too. i do have a set of IFS rotors from an 86 runner, but comparing the bolt pattern on the IFS rotor and the rear axle shaft, they obviously dont match. the rotor would have to be drilled to match, which may be worth it since the IFS rotor is vented.  i believe my friend has some straight axle solid rotors i could buy for cheap. im going to compare the spacing on the two different types of rotors and see which will fit best.

i do have one question...... on the rear axle, is it better to have the caliper on the front side of the axle or the rear?  i dont know how you are supposed to determine that

[boggerunner]

i dont know if it matters if its on the front or back side

[82 HiLux]

ok thanks

[THK]

I'll come back on the 31st so I can finally rear your writeup I've been waiting for.

[93tonkatoy]

Caliper placement should be most dependant on where the bleeder screw is. It needs to be at the top of the caliper to make bleeding possible. Front or rear or top, doesn't really matter. Also, make sure the caliper will have enough clearance with the rim installed.

[boggerunner]

pics are working again!