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Front Caliper Upgrades?

Discussion in 'HardCore Corner' started by srgould41, Feb 5, 2013.

  1. srgould41

    srgould41

    Messages:
    1,085
    Location:
    Federal Way, WA
    I am running large pattern pick up knuckles on my front FJ40 axle. I have a 1" master, dual diaphragm booster, the larger 4Runner calipers and late FJ40 vented rotors, but my front brakes don't stop worth a darn.


    Does anyone know of a conversion to larger piston calipers? Maybe Monte Carlo calipers? I know there is a conversion for small pattern FJ40 drum front axles, but how about disk axles? Anyone know of something? My searches have drawn a blank.


    Thanks
  2. bustanutley

    bustanutley

    Messages:
    2,287
    Location:
    denver
    A 1" master is probably too big. Do you still have drums in the rear? I basically have an early Tundra brake system in my 40 which has has a little bigger calipers than the 4runners and late model drums in the rear, the master on my tundra and my 40 is a 7/8" unit. My pedal was always soft in the 40 but that wass because I was using the original manual brake mounting point (6:1 ratio). I have just moved the master down an inch (4:1 ratio) which should make them feel much better.

    read this: http://www.pirate4x4.com/tech/billavista/Brakes/
  3. srgould41

    srgould41

    Messages:
    1,085
    Location:
    Federal Way, WA
    I have Monte Carlo disks in the rear.

    I actually moved my mount point higer for a 7:1 ratio.
  4. hotwheels

    hotwheels

    Messages:
    8
    I ran into this problem on my old 4runner. SAS'ed fj40 venter rotors in front with bigger 4runner calipers. Disc brake conversion in rear with monte carlo calipers. Dual diafram brake booster and a 1" bore master cylinder. After bleeding the brakes I had a very soft pedal and almost went to the floor before stopping. I upgraded to the 3/4 ton GM master cylinder and fixed my brake problem. The monte carlo calipers use more fluid in the rear the the front 4 piston toyota calipers. The GM master cylinder moves more fluid and stops the soft pedal.
  5. srgould41

    srgould41

    Messages:
    1,085
    Location:
    Federal Way, WA
    I am actually using a GM 1" Corvette master and aftermarket 9" dual booster.

    The smallest GM master I can buy is a 15/16". It should add about 25% greater pressure. I worry about the travel, though. I might not have enough room. I can move the attach point lower down to help that issue, but then I lose the ratio advantage...

    That's why I posted about larger calipers... That would be ideal.

  6. hotwheels

    hotwheels

    Messages:
    8
    I was usinga 3/4 tons 4x4 Gm master off a 1978 truck 1.25" bore. The solved all my pedal problem. My runner brakes were better after I did thes mod. Rockstomper.com sells the toyota booster adapter to Gm master cylinder and the master in a kit for 100$
  7. srgould41

    srgould41

    Messages:
    1,085
    Location:
    Federal Way, WA
    If I used a 1.25" bore master I would have a great short pedal travel, but not be able to stop at all.

  8. bustanutley

    bustanutley

    Messages:
    2,287
    Location:
    denver
    You won't want to hear this, but, the monte carlo calipers are the problem. You have bigger calipers in the rear than the front, this is very poor brake system design. I have never understood why this is a common swap for toyotas. Also, changing to a bigger master cylinder and then increasing the leverage ratio negates the bigger master.... :)

    The first thing I would do is ditch the monte carlo calipers for something like half the size, or, go back to drums in the back.
  9. srgould41

    srgould41

    Messages:
    1,085
    Location:
    Federal Way, WA
    I am not fond of those calipers either! They are a 2.5" piston. I found some 2" piston calipers that I plan to install when I tear into the brake system. That said, lots of people use this combo and report good results.

  10. hotwheels

    hotwheels

    Messages:
    8
    Bustanutly is right. When I used the set up I told you about I had a perfect pedal and my runner stopped on a dime with 38s. Perfect pedal travel and great stopping power.
  11. bustanutley

    bustanutley

    Messages:
    2,287
    Location:
    denver
    Monte carlo single 2.5" pistons yield a 4.9in^2 surface area. Late model toyota front calipers yield and effective 4.46in^2 surface area. Do you think it is a good design to have more stopping force in the rear than the front? Sure you can dial a proportioning valve down to near zero in the rear to make it kinda work, but why? Going to a bigger master will move more fluid but at lower pressure and that will never result in more braking force in the front.

    Moving to smaller calipers in the rear will fix the problem.

  12. Josie'sLandCruiser

    Josie'sLandCruiser Stop calling it a "FJ." SILVER Star

    Messages:
    4,483
    Location:
    Seattle, USA
    Hi All:

    Great thread! :beer:

    You guys have explained how the different parts in a brake system work together. I never even thought about things like the pedal location.

    I have always thought that the typical "Monte Carlo" front brake calipers on the rear axle seemed like a bad idea, but have never heard of any other caliper choices.

    IIRC, Steve has found (through a hot rod site) a disc brake rear axle caliper that *may* be a better choice than the Monte Carlo front caliper that will be an easy swap.

    Regards,

    Alan
  13. Boing

    Boing

    Messages:
    182
    Location:
    Woodland Park
    The sweetest Toyota brakes period, are late model Lexus GX470 rotors and calipers. But they do require 17" wheels. The will hard lock 37's with ease, on the back I would go with either solid front axle minitruck calipers and solid rotors. Or SW13's and use the rotors you have in the front.

    Brian makes them in two different flavors, one for the early and one for the 2005 and on (you have to specify what you want). Can look on pirate their is alot of info in his thread on these calipers. We have installed them on several trucks and by far they are the sweetest Toyota brakes we have used.

    http://frontrangeoffroadfab.com/nfo...d=136&osCsid=c5ac0bc09635f7bf4039dd4312ab5e34


    Something like this is what we like in the back. Keep the rear calipers small otherwise you will fight it locking first...
    http://www.davezoffroadperformance.com/store/suspension/brakes/rear-disc-brake-brackets.html


    This combo gives very minimal pedal effort and stops on a dime! Like I said it will hard lock 37s with ease... Oh yeah and an FJ-80 master works like a champ for this setup. If you want a good primer on hydraulic ratio's check this out.

    http://home.4x4wire.com/erik/4runner/brakes/
    Last edited: Feb 6, 2013
  14. Tapage

    Tapage Club 4X4 Panamá SILVER Star

    Messages:
    20,630
    Location:
    Panamá
    I'm at 1" MC with front SW13 calipers and rear eldo calipers .. I did try this combo with 1.25 all the way down to 1" MC and nothing bigger than 1"MC works for me ..
  15. Tigerstripe40

    Tigerstripe40

    Messages:
    1,714
    Location:
    Utardia
    I have V6 4Runner calipers in the front and monte carlo calipers in the rear, and a proportioning valve on the rear brake circuit.
    With the stock master cylinder, the truck wouldn't stop very well.
    I swapped it out for an 80 series non-abs master cylinder with a 1" bore.
    After getting the proportioning valve dialed in, the truck stops better than ever.

    People go with the monte carlo calipers because they are cheap ($12) and available at most auto parts stores and once you've got the proportioning valve dialed in, work awesome.
  16. srgould41

    srgould41

    Messages:
    1,085
    Location:
    Federal Way, WA
    I never tried with the stock master because I swapped in a 1" master when I upgraded to disks. I know two people with 4 wheel disk mods using the stock master and a rear proportioning valve without issue.

    Before I started adjusting my rear prop valve I could stop on a dime. I took it into the dirt to start adjustments. I had to dial it all the way to its max setting to even get the rears close to not locking before the front. Now the brakes suck which tells me the rears were doing all the work of stopping the truck at first.

  17. Bad Mojo

    Bad Mojo

    Messages:
    911
    Location:
    New Mexico
    Here is what I have gathered from this thread and others. Lets see if I am right.

    Option 1:
    Upgrade to V6 calipers on either FJ40s, FJ60s, or SFA mini trucks

    Option 2:
    Upgrade to the FROR bracket, which should work for large pattern knuckles (79+ FJ40, FJ60, and SFA Mini trucks) Use Tacoma brakes and calipers, but will require 16" rims in most cases. This also means getting IFS hubs.

    Option 3: Upgrade to the FROR bracket, which should work for large pattern knuckles (79+ FJ40, FJ60, and SFA Mini trucks) Use tundra brakes and calipers, but will require 16" rims in most cases. The jump to from Tacoma to Tundra is pretty common. This also means getting IFS hubs.

    Option 4: Upgrade to the FROR bracket, which should work for large pattern knuckles (79+ FJ40, FJ60, and SFA Mini trucks) Use late model 4Runner or GX470 caliper and rotor which are the same part. These require 17" rims. This requires use of IFS hubs.

    Option 4 seems to have the must stopping power, but also requires the largest step up in rim sizes. On my own build I have 62 knuckles and are needing new rims and tires, so this does seem like a viable option because I don't mind the look of 17" FJ Cruiser rims.

    My question is for options 2-4 does using the IFS hub change the backspacing, and if so how much?
  18. bustanutley

    bustanutley

    Messages:
    2,287
    Location:
    denver

    The IFS wheel hub adds about 1.5" of width per side.

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