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Gettin the Brakes

Discussion in '40- & 55-Series Tech' started by Eternal, Mar 2, 2003.

  1. Eternal

    Eternal

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    OK, so I am pickin up the parts to get ready for the 4 wheel disc conversion on my 70 40. I met a guy that has built a bracket that will mount Toyota calipers for the back. He has 4 piston on the front and 2 piston on the rear and he says that you don't need a porportioning valve if you do the set up that way. Is this true or do you think that it might just be for his rig. He runs 44's and I got 31's. I am also gonna go with the S-10 master from the tech section like Mike Smythe. Also any thoughts on going with 2 versus 4 piston on the rear?

    Let the stock piling begin.....

    Eternal-forever
     
  2. sfrolich

    sfrolich

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    Hi,
    I'm just going through the nightmare of fixing a 4 wheel disc job a shop did for me. My kit has Monte Carlo rear disc brakes (using a conversion bracket) and an whole front axle from a late 70's FJ40. The back is one really big piston while the front is really small four piston. With the stock proportioning valve my back brakes lock early.

    I don't know about Toyota back brakes but if you are using the front axle setup I have, get calipers from a 92 4Runner which has much bigger pistons. You will need to grind the backing plate a little and maybe grind off some of the cooling fins on the calipers to make them not hit the wheel but it is worth the trouble.

    A proprtioning valve is only $40 at summit racing and it will let you fine tune your brakes to work the way you want so I stongly recommend it.

    Don't forget to take the residual valves out of your master cyl!

    I also have a disc brake booster with a late 70's master cyl but you can give your existing master cyl a try to see if everything works to your satisfaction.

    Hope this helps. Scott
     
  3. beanz2

    beanz2 Moderator

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    Curious what Toyota caliper has 2 pistons, a 2WD Toy truck front? A rear toyota caliper is usually a single piston, floating caliper design much like a Chevy design, just smaller. The only problem is often the caliper is designed for much smaller diameter rotors. Guys use ventilated 6 lugs rotors from Chevy truck fronts for cruiser conversion, but may be you can look at other 6-lug Japanese small truck/SUV front rotors e.g. Amigo, B2000. etc. for a smaller diameter one.

    IMO most of braking power is from the front brakes anyway (assuming forward motion :) ) so going big on the rear is not helping that much unless you go bigger up front like Scott says.

    Dave
     
  4. Eternal

    Eternal

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    I believe that the calipers came off a 84 or 86 2wd deisel(shouldnt make a difference but...) pickup. They are the same as the chev's but a little bit smaller and the pistons are bigger and they are cheaper and Toyota(heard that they tend to last longer and fewer problems, I can believe that). It is just that I have a couple calipers extra that are 4 piston(for cores) and I want to use them if I can. I guess the valve isn't as much as I was told. I heard about $100 for an adjustable. It shouldn't be detrimental to me if I put those 4 piston on though or is it? I want to make sure that I have all my info straight before I get going on this project. The more info I can gleen now the less anxiety when I have the problems that are going to occur at install time. HAte to install them and have them lock up and not be able to adjust them properly. Don't think that would be a problem but hey what do I know. More than I did yesterday that is for sure.


    Eternal-forever
     
  5. beanz2

    beanz2 Moderator

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    The adjustable prop valve is about $40 at Summit or Jegs. The 4 piston caliper will work fine, I run them in the back too with the '92 4Runner calipers up front so there is still more braking force up front than the back.

    Just curious if you want all Toyota calipers, why you want an Chevy S-10 master cylinder. You can get 1" bore 4WDB master cylinder off a 1993-94 FZJ80 that will bolt up to your Toyota booster. It will move plenty of volume. What is the bore on the S-10 master cyl?

    Dave
     
  6. Eternal

    Eternal

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    I heard that the toyota calipers are less likely to have any future problems with them and will be able to handle any size of tire that you may want to put on. Some of the guys around here get only about 2-3 years out of a set of chev calipers. Now they probably do abuse their rigs more than I do right now, but you never know I may turn into one of them(most of you out there) eventually. As for the S-10 master I don't have a booster on mine and I don't really want to get into the cutting and moving the clutch cylinder to accomodate it. I was told that it wasn't really neccessary for the conversion but that I need a 2 chamber master and the price seems to be good, so waalaa there you go. It was the easiest conversion on the tech links as well. Any other comments would be greatly appreciated. I expect in the next couple of weeks to get everything together for the conversion.


    Eternal-forever
     
  7. bull

    bull

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    Don't forget to take the residual valves out of your master cyl

    What exactly is this?
     
  8. woody

    woody Internet Fireman Staff Member

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