DR. DIFF 11.25 rear Disc Brake Kit

Brakes for your Classic Mopar

  1. Heywodja

    Heywodja The Heartbeat Stops Here FABO Gold Member

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    • dano

      dano Evil Handy Man

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      Looks like the "Ford Explorer" kit that will fit many different rear ends. My dad has it for his 9".

      What do you want to know? Cass supports what he carries really well, might ask him.
       
    • Heywodja

      Heywodja The Heartbeat Stops Here FABO Gold Member

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      I was just wanting to know if there were any general issues with install or such. I want to order one and hate to grill Cass.. Thought i might do a little homework first..
       
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      • Kern Dog

        Kern Dog FABO Gold Member FABO Gold Member

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        Explorer OR the Jeep Liberty brakes that Rick Ehrenberg wrote about?
         
      • Heywodja

        Heywodja The Heartbeat Stops Here FABO Gold Member

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        I have the 11.75 mopar discs up front, there outta be no stopping issues.. LOL
         
      • dano

        dano Evil Handy Man

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        The kits works, its far better than the GM caliper kits everyone sells for cheap. My question would be does it work with your axle spacing? As in the distance from housing flange to axle flange. Looks like you'll need to modify/fab hard lines.

        FYI I did Dr Diff's 11.625 rears and the longer axle studs didn't work with my very old Dutchman Axles, I had to get them from Dutchman.
         
      • goldduster318

        goldduster318 Overzealous Car Modifier

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        That's a different kit than the one most people have. This is the explorer based kit with the drum in hat parking brake.

        The other kits, the 10.7 and 11.7 kits are based on the 94-04 Ford Mustang Cobra and have a parking brake in the caliper. I have the 11.7 kit and the custom parking brake cables, all of which are good.

        This is the 11.7 Cobra based kit for comparison
        [​IMG]

        All of these kits require you to make your own hard lines on the axle.

        As to which one is better, it kind of depends on what your front brakes are, this kit is probably better with "stock" fronts where the cobra kits are great if you have cobra fronts (his 13" kit)
         
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        • jbc426

          jbc426 Well-Known Member

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          Why do you need such big rear brakes? I have Dr Diff's small rear econo kit brakes, from a 2005 Mustang Cobra I believe, and they match perfectly (front to rear bias) with the 11 3/4" Police Taxi fronts I got from him. No need for any adjustable proportioning valve at all.
           
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          • Heywodja

            Heywodja The Heartbeat Stops Here FABO Gold Member

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            Not sure... might be the same reason I need 500HP, just sayin..
             
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            • dodgedifferent2

              dodgedifferent2 Well-Known Member

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              Internal drum parking brakes have been my nemesis since the dawn of rear disc brakes.
               
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              • Heywodja

                Heywodja The Heartbeat Stops Here FABO Gold Member

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                Why is that?
                 
              • dodgedifferent2

                dodgedifferent2 Well-Known Member

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                They seize up, rust up then Heat up rotor which takes out pads, rotor and sometimes caliper. Also destroys shoes. Then you get a giant groove and cant get rotor off because shoes are caught. Turns a simple job into a nightmare.
                A simple brake job turns into replacing the shoes everytime you change pads and rotors. Gets expensive on the 2500 rams
                If i used it regularly. Who does that? Maybe it would last.
                 
              • Heywodja

                Heywodja The Heartbeat Stops Here FABO Gold Member

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                They seize up, rust up then Heat up rotor which takes out pads, rotor and sometimes caliper. Also destroys shoes. Then you get a giant groove and cant get rotor off because shoes are caught. Turns a simple job into a nightmare.
                A simple brake job turns into replacing the shoes everytime you change pads and rotors. Gets expensive on the 2500 rams
                If i used it regularly. Who does that? Maybe it would last.

                So is it the consensus that the mustang caliper kits are a more simplistic and reliable system?
                 
              • jbc426

                jbc426 Well-Known Member

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                What are you using up front to match these big rear brakes? Maybe 13" with Viper Calipers or something massive like that?

                All the Mopars I have ever owned tend to lock up the rears way before the fronts break loose. I've had to use smaller rear wheel cylinders on the rears to "calm" them down before switching to small rear discs like Dr Diff's Econo rear brake kit in combination with the Mopar Police Taxi front brakes with Firm Feel pads. That combination is nearly perfectly balanced on both My A-Body and E-Body. No additional proportioning valve needed.
                 
              • 72bluNblu

                72bluNblu FABO Gold Member FABO Gold Member

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                It really depends on your car. I run DoctorDiff's 13" cobra brakes up front with the 11.7's out back, they're very well balanced. I only use a very small amount of adjustment on my adjustable prop valve, it's almost wide open.

                But I also run a stagger, 275's in the front and 295's out back. And if your car has some rake to it you'd also need to dial the rear brakes back as you're loading the front even more. The brake bias needed can be pretty different car to car depending on the suspension and tire set up.

                I haven't looked into the caliper set up on the 11.25's, so the other thing to keep in mind is that just because the rotor is a little bigger doesn't necessarily mean there's more braking force. If the caliper has a smaller piston bore it could be pretty similar to the 10.7's.
                 
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                • Heywodja

                  Heywodja The Heartbeat Stops Here FABO Gold Member

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                • goldduster318

                  goldduster318 Overzealous Car Modifier

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                  The Explorer calipers are a 48mm piston and the Mustang Cobras are 38mm piston according to RockAuto's catalog.

                  On Drum in Hat vs integrated into caliper - the drum in hat system has superior hill holding torque due to the wedging action and physical size of the shoes vs the small brake pads. Other than rust, my opinion is its a less troublesome system than integrated into the calipers. It just has to be adjusted correctly so it's not dragging so much and of course all the cables to release, but you could have similar issues with the integrated calipers. The integrated calipers seize occasionally too and there is an additional hydraulic leak path. Now, with that being said I have had both types and really only had a failure of the integrated calipers, yet still chose them for my Duster.

                  I just worked on a Jeep Patriot last summer which is basically hashed (2013, 141k, all time spent in midwest salt-fest winters) with a drum in hat that was barely used and everything still worked fine and it came apart without needing to replace anything. Was doing wheel bearings on it. The boots were tore on the calipers and the pins were seized so it had already trashed the pads there too.
                   
                • DionR

                  DionR Well-Known Member

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                  One other advantage to the drum in hat EB is that the calipers can be a fixed rather than floating calipers without having to use an additional mechanical caliper for the emergency brake. Not something I see anyone doing, but something I wanted to do someday and so it was a deciding factor for me.

                  I have had far more problems with calipers that have a built in e-brake setup than the drum in hat style. Just seems like I spend an inordinate amount of time trying to get the piston back into the caliper when I do a brake job. Pretty sure most shops don't even entertain the idea of using the existing calipers and always replace them when doing rear brakes on cars with calipers with the e-brake built in.
                   
                • Kern Dog

                  Kern Dog FABO Gold Member FABO Gold Member

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                  355,000 miles on my 2007 Ram 1500 with the design you mentioned.
                   
                • goldduster318

                  goldduster318 Overzealous Car Modifier

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                  You just need one of these tools:
                  https://www.amazon.com/dp/B0122Q83T4/?tag=fabo03-20

                  They work well, just be careful to read up if it's an electric caliper. If they don't turn when you push them in they likely won't go. Some of them might have seized. The electric ones are going to be spendy to replace. Any shop that just replaces them if they would wind back in with this tool is one nobody should be going to.
                   
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