rear disc break conversion with toyota calipers?

Discussion in '79-95 Toyota Truck Tech' started by bryan89, Oct 19, 2011.

  1. bryan89

    bryan89

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    Location:
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    i dont plan on doing this like tomorrow or anything, but its on my list of stuff to do eventually.

    anyway, i have seen on other forums and places where guys are doing a rear disc conversion on early mini trucks, but they are using domestic calipers to retain the e-brake (i guess)

    if i did this i would want to use all toyota stuff. does anyone know of a toyota caliper that has cable style e-brake hook up on it? or did no toyota come with factory rear discs?

    i think the fj80s had discs out back, but what did they do for ebrake?
  2. pappy

    pappy photosynthesizing Moderator

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    Lots of newer Toyotas with rear disk brakes. Adaptable to an early gen 4x4 axle? With enough time, money, and research I guess anything is possible. The rear wheel disk trucks use a parking brake inside the "hat" of the rear rotor. It's sort of a drum brake inside the disk. I've talked with folks who considered the options, but bailed on the thought in the long run.

    Maybe there is an application that would allow you to swap in a complete rear disk axle. I don't know.
  3. bryan89

    bryan89

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    786
    Location:
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    yeah,
    im not worried about fabrication of brackets and getting rotors to fit.
    that is the easy part.

    all i am concerned with is finding a caliper that will physically fit in the volume of space enclosed by the wheel and has the capability to mate to the stock e-brake mechanism, which is a cable system.

    it appears as though 4crawler has used a supra caliper, as it has the e-brake cable, but i couldn't find a write up on it.

    anyways, it was just a thought. i didnt think it would be that difficult if you could find a proper candidate.
  4. KLF

    KLF Frame waxer

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    5,540
    Location:
    Southern NH
    Early Supras had calipers with an integrated e-brake. But, it just doesn't work well, it's like you can't generate enough "grip" with them with the stock truck cable, so the e-brake is not effective.

    The FZJ80 setup is like the newer ones, there is a drum-style brake that works inside the "hat" of the rotor. My cars are the same. Too complicated, IMO.

    I have Monte Carlo calipers on Sky Manufacturing brackets. Cheap, easy, and simple. Loaded calipers are about $15 each from NAPA. It's a tight fit with 15" rims, requires grinding on the calipers a little, but I'll be upgrading to 16" rims when I get my truck back on the road. I also have an old All-Pro t-case e-brake setup.

    You need floating calipers on the back, due to the SF design of the axle. Too much runout to use a rigid caliper like is on the front, you'll go crazy with a soft pedal.
  5. GRM

    GRM Profesional at Something Moderator

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    The word on the street is the next big thing will be to run taurus rear calipers with 88-92 chevy 1/2 ton rotors. You'll prob see that kit come out in the next year.

    As for going all toyota... going to need to run the fj cruiser/4runner/fzj80 rear disk brake setup with internal drums. Its not super-hard to put together, but is a challenge.

    Another option is to run the mini truck front calipers & rotors, then move the parking brake to the transfer case.
  6. NorCalBorn

    NorCalBorn

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    1,863
    :bounce: Hmmm, and run full floaters too?? :popcorn:
  7. pappy

    pappy photosynthesizing Moderator

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    I used to have the TC parking brake on my 4Runner. Worthless.
  8. Combat Chuck

    Combat Chuck

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    Front Range Offroad sells rear disc conversion kits that use Supra Calipers, allowing for both retention of e-brake, and stock MC.
    It may be unique to their full-float kit, though.
  9. KLF

    KLF Frame waxer

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    5,540
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    Interesting. I love my All-Pro one, works great. It's pretty old (~10 years IIRC), first generation. I need a new caliper for it, the pads are finally about shot.
  10. pappy

    pappy photosynthesizing Moderator

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    Exactly what I have. Don't hold worth a darn.
  11. bryan89

    bryan89

    Messages:
    786
    Location:
    Charleston, SC
    that is kind of what i was worried about when i considered using the toyota calipers with no ebrake cable mount.

    it seems to me like the leverage inherent of the ring and pinion ratio is stacked up not in your favor when the break is on the transfer case. its like you are basically trying to hold the pinion from turning while someone is grabbing the tire and spinning it. the person on the tire has all the added benefit of the leverage from the gear ratio.

    seems like it would be even worse if you have big gears (ie 5.13s, 5.38s etc) in your diff for bigger tires. the Moment arm is even longer.

  12. GRM

    GRM Profesional at Something Moderator

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    You could. Brian @ Front Range did a kit for a friend of mine to run the FJ Cruiser Parts on his full float kit with a diamond housing. It was super-slick.

    [​IMG]
    Last edited: Oct 20, 2011
  13. KLF

    KLF Frame waxer

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    5,540
    Location:
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    Pretty sure you have the leverage backwards. Let's say you have a 4:1 ratio ring-to-pinion gearing (to make it easy). That would mean you would have to turn the pinion 4 times for each spin of the ring gear. So the pinion side has the leverage advantage.

    Not sure what was up with Pappy's, but mine will hold the truck very still, at the limit of tire traction. It is kinda fussy to get it adjusted just right: too tight and it rubs on the rotor while you're driving down the road, too loose and you don't get enough force on the rotor when you set the brake.

    The only downside is the truck can be rocked back and forth a little with this brake set, due to the backlash in the rear diff. The other is that if you have an open diff, and you lift one wheel off the ground, the e-brake no longer holds, as the lifted wheel will spin. I solve this by either locking the rear diff, or locking the front hubs and putting it in 4WD so the front wheels hold the truck still. Installation is a PITA too, you have to remove the output flange from the back of the t-case to get the rotor on, which means a new seal and stake nut. You can't get a ratchet/impact on the bolts that hold the brake to the t-case, so it's a lot of tedious wrenching with open ends and GearWrenches.
  14. bryan89

    bryan89

    Messages:
    786
    Location:
    Charleston, SC
    klf is right.
    i realized i had it backwards after i posted. i was thinking about a constant force trying to make torque, not torque trying to make force.

    even still though, wonder what the bearing load on the back of the transfer case becomes, not being designed to sling around a rotor at several thousand rpms? wonder if it would cause leaks from wearing out prematurely. guess if it was balanced right it would be ok.

    also, can you use the transfer case break kit with ifs? is there any cross member mods that are required that wouldnt be possible with ifs?
  15. KLF

    KLF Frame waxer

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    5,540
    Location:
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    I haven't had any leaks yet, this is the 2nd truck I've installed it on, probably approx 100K miles total.

    IFS doesnt effect the setup, and no x member mods required. I cut off all the t-bar mount stuff from my frame so I did have to fab a mount for the front cable to hook to, and if you have a lwb truck you have to get a new front cable, it needs to be the short cable.
  16. NorCalBorn

    NorCalBorn

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    1,863
    Pretty much how I secure my rig if working on the rear any time. It adds a measure into having blocks around the wheels, just in case. For that matter, I still put the trans in 1st and 4-lo when parked around my parents property, parked offroad, or while camping too. Only downside is if say some idiot slides on the icy street into my rig I have to worry about chipped teeth and gears.


    Thanks, I knew it was someone you knew, but couldn't find the info or pics easily enough. ~The FJ-C conversion IMHO is the sweetest one so far. Ask your buddy to please post up the conversion in here for us to see how it all came together nicely.
  17. GRM

    GRM Profesional at Something Moderator

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    You can read about it here: Project SAC'D FJC - Phase II - Toyota FJ Cruiser Forum
  18. jynx

    jynx SILVER Star

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    Anyone know if the FJ "kit" can be had or if it is a special order type item? Would be curious what something like that would run. A rear set up like that would be a nice addition to any rig, 9.5" diff, late model discs, FF. Definitely a sweet setup.
  19. NorCalBorn

    NorCalBorn

    Messages:
    1,863
    LOL, or just know that Sol's running a diamond now. I didn't know he did that..next time I talk or chat (via FB) with him I'll have to see what the part#'s are and if the 4 bolt pattern for them is similar to the 90-95 8" rear diffs.

    :D Thanks!

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