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GT Mustang to 13" Cobra brake Avanti upgrade (RP)

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  • GT Mustang to 13" Cobra brake Avanti upgrade (RP)

    The original post got archived and its apparently impossible to take
    from archive. It can not be edited while archived, and my pictures
    are in a new location since posting.

    Originally Posted - 07/19/2006



    I got a set of front brake hubs from a guy who had recently upgraded to
    Turner disc brakes from his tired 4 wheel stock drums. I pressed the old
    drums off the hubs, and then trial fitted the stock hub into the 13" Cobra
    rotor, and it fit perfectly - that was a BIG relief! :



    The next step was to press out the old studs :







    Here is the studless hub :



    Did you know that the factory studs have NO knurl?? No wonder they tend
    to strip out so easy with an impact gun!



    They looked SOOO ugly, I scraped them with a screw driver, and the took
    them to work and used the wire wheel :










    Thats all for now .. I had to order the new wheel bearings, seals, caps, and
    also make a tool to pound out the old races. The caps I got from Pepboys
    in the Help! section, but the part that slips into the hub was too long, so it
    would not sit flush, hub against the crimped shoulder. I also bought the 10
    Dodge wheel studs mentioned in my original article, and drilled the hub for
    the interference fit for the knurl. I took two of the old bearing races, one
    of the inners, & one of the outers, and had the machine shop at my work
    cut a slot through one side with the chop saw. This will allow me to use as
    an installer, so I dont risk damaging the new race with an out-of-control
    chisel tip! I went to buy a bearing race installer kit from the local Harbor
    Freight, but they were sold out! I will update this thread as I go.

    Enjoy!

    Tom

    '63 Avanti, zinc plated drilled & slotted 03 Mustang Cobra 13" front disc/98 GT rear brakes, 03 Cobra 17" wheels, GM alt, 97 Z28 leather seats, soon: TKO 5-spd, Ported heads w/SST full flow valves, 'R3' 276 cam, Edelbrock AFB Carb, GM HEI distributor, 8.8mm plug wires
    '63 Avanti R1, '03 Mustang Cobra 13" front disc/98 GT rear brakes, 03 Cobra 17" wheels, GM alt, 97 Z28 leather seats, TKO 5-spd, Ported heads w/SST full flow valves.
    Check out my disc brake adapters to install 1994-2004 Mustang disc brakes on your Studebaker!!
    http://forum.studebakerdriversclub.c...bracket-update
    I have also written many TECH how to articles, do a search for my Forum name to find them

  • #2
    Got out there tonight and drilled the holes out in the new rotors. Thought I
    would show a couple pics, the rear rotors had smaller holes, but this could
    be because they are "aftermarket". Used the 5/8 drill and went to town:

    Rear:



    Front:



    Sorry about those pics, I dont know WHAT the camera was focusing in on,
    it certainly WASNT the rotor. Hummm.

    Here is a couple shots of how little material had to be removed from the
    front rotor holes, here is one drilled through :



    Here is a partial drilled hole. Not a lot to remove :



    Close up :



    Tom
    '63 Avanti R1, '03 Mustang Cobra 13" front disc/98 GT rear brakes, 03 Cobra 17" wheels, GM alt, 97 Z28 leather seats, TKO 5-spd, Ported heads w/SST full flow valves.
    Check out my disc brake adapters to install 1994-2004 Mustang disc brakes on your Studebaker!!
    http://forum.studebakerdriversclub.c...bracket-update
    I have also written many TECH how to articles, do a search for my Forum name to find them

    Comment


    • #3
      The next step was to remove the old bearing races, & install the new ones.
      I added some Loctite & then tapped the new races in until they were flush
      with the hub surface. I have installed bearing races this way for years, it
      just requires that you continue to hit the race in a "star pattern", like you
      torque wheel studs. This keeps the race from getting stuck :



      Then I used my two cut old races to tap the rest of the way until the race
      was against the machined step inside :









      Then I pressed in the Dodge shouldered studs :







      Finished hub, waiting to go on the car :



      Then I had to remove the Mustang GT rotors, calipers, & the modified hubs
      to make way for the unmachined hubs. The machined hubs are going to
      Michigan to go on my dads 1969 Avanti II.





      Clearance for wrenches is tight, but it works :



      Drained out some brake fluid. As you can see, the prototype brackets got
      some extra holes, that was to rotate the caliper up, to get the bottom bolt
      higher then the steering arm, so a standard wrench could be used on the
      top and bottom bolt, and tightened to 85 ft lbs :



      Then pack the bearings, add the new seals (Napa now carries an updated
      neoprene seal, was glad to toss the old felt ones!!), bolt it on the spindle,
      new cotter pin, and add the modified "Help!" dust cap (not a direct fit like a
      cross reference site for Studebaker listed!).











      Tom
      '63 Avanti R1, '03 Mustang Cobra 13" front disc/98 GT rear brakes, 03 Cobra 17" wheels, GM alt, 97 Z28 leather seats, TKO 5-spd, Ported heads w/SST full flow valves.
      Check out my disc brake adapters to install 1994-2004 Mustang disc brakes on your Studebaker!!
      http://forum.studebakerdriversclub.c...bracket-update
      I have also written many TECH how to articles, do a search for my Forum name to find them

      Comment


      • #4
        Once the Dodge studs are in the stock Stude hub, the rotor is an easy step
        of tightening the lugs on, to draw the rotor onto the shoulders.





        Then, the Cobra caliper gets bolted onto the bracket. With the thickness I
        chose for the bracket at the mounting point, I found the perfect length of
        bolt at Ace Hardware, though the size could be picked up anywhere.









        Here is a shot looking over the Cobra caliper at the lower mounting bolt,
        this shows how close the extention is to the steering arm, but it works!



        Here is a shot of the upper mounting bolt, again close, but it clears! These
        are BIG calipers, so they have a wide spread on the bolts.



        Tire back on the drivers side, now off to do the passenger side.







        Tom
        '63 Avanti R1, '03 Mustang Cobra 13" front disc/98 GT rear brakes, 03 Cobra 17" wheels, GM alt, 97 Z28 leather seats, TKO 5-spd, Ported heads w/SST full flow valves.
        Check out my disc brake adapters to install 1994-2004 Mustang disc brakes on your Studebaker!!
        http://forum.studebakerdriversclub.c...bracket-update
        I have also written many TECH how to articles, do a search for my Forum name to find them

        Comment


        • #5
          I thought I would show the inner hub seals from Napa, the part number is
          in the picture. They are nice, because they are not felt, but are a little bit
          more difficult to install on the spindle, the rubber edge doesnt slip over on
          the seal surface like the felt. I finally used the nut to put pressure on the
          seal, and then rotated the hub and the seal popped on.





          Hub on the passenger side spindle :







          Rotor and caliper assembled :





          Unfortunately, I found that the passenger side GT brake hose, does not fit
          on the Cobra caliper. The locating boss interferes with the block on the
          hose (these are banjo fittings). Not sure how I will correct his, I have the
          stainless steel braided hoses, but some prelim comparisons made me think
          that the braided lines can not fit where the rubber lines are, since the dont
          bend as easily as the rubber! A speed bump .... I'll figure it out!

          Tire assembly back on the passenger side :



          Is this a freaking BIG brake or what? I guess I have now officially taken
          away Steeltech's claim of the "biggest brakes available for Studebaker".
          Sorry Dave! Though yours still fit inside 15" wheels. These wont!





          Tom
          '63 Avanti R1, '03 Mustang Cobra 13" front disc/98 GT rear brakes, 03 Cobra 17" wheels, GM alt, 97 Z28 leather seats, TKO 5-spd, Ported heads w/SST full flow valves.
          Check out my disc brake adapters to install 1994-2004 Mustang disc brakes on your Studebaker!!
          http://forum.studebakerdriversclub.c...bracket-update
          I have also written many TECH how to articles, do a search for my Forum name to find them

          Comment


          • #6
            In my effort to keep you all informed of the good AND the bad in this mod,
            here is the latest :

            After getting everything together on the car, I took it for the maiden
            voyage and it was pretty obvious on the first stop, that something was
            not right. The pedal was pulsating pretty good. These were two "new"
            hubs that I had to history for, so I did some research on the max rotor
            runout thats allowable. The spec I found was .005 at the rotor, which
            translates to about .002 at the hub. I checked both sides, and one was
            at .007, and the other was over .010! I was able to "correct" the .007
            side to .0025 by removing the rotor, and hitting the "high" side with
            my trusty BFH (Big Freakin Hammer). The hub was about .003 out, and it
            was only in one localized area. A couple sharp blows got me .001 out.
            With the rotor back on, that translated to .0025, which is within the
            .005 max (.003 preferred). The other hub was .005+ out, & it was over
            a 180 degree arc. It was pretty obvious that the BFH wasnt up to the
            task of correcting that much error. So off the hub went, pressed out
            the studs, and brought it to work and had Bobby take .006 off the front
            side. Will try it on the car when I get home (before putting the old
            studs back in) and see if its within .002 (.001 preferred).

            Heck, if adapting brakes was easy - everyone would be doing it!

            Tom
            '63 Avanti R1, '03 Mustang Cobra 13" front disc/98 GT rear brakes, 03 Cobra 17" wheels, GM alt, 97 Z28 leather seats, TKO 5-spd, Ported heads w/SST full flow valves.
            Check out my disc brake adapters to install 1994-2004 Mustang disc brakes on your Studebaker!!
            http://forum.studebakerdriversclub.c...bracket-update
            I have also written many TECH how to articles, do a search for my Forum name to find them

            Comment


            • #7
              I think I mentioned that the stock Mustang GT front hoses didnt fit the new
              Cobra calipers. The problem was that the boss on the hose end, that the
              banjo fitting bolt goes thru, is in a different spot on the pass side caliper.
              The GT caliper has the boss in the bottom, the Cobra has it on the top on
              both sides. To get the GT hose to fit, I needed to match the boss :









              Here is another shot of the steel hose bracket I made. I made a drawing
              for this, to make it easier to make another set.



              Then I had to machine that hub, to get it right took two tries! It must have
              been bent, since the pass side hub only needed a good wack to get it to be
              within spec on runout. I would assume that a standard brake lathe could
              be used to "true" up a hub before new bearings are installed. The other
              fix would be to "true" the rotors with the hub bolted into them. I was not
              able to do this, as you arent supposed to "turn" drilled and slotted rotors.





              Then I went on too the rear brakes. I could have gone to Cobra rears, but
              that would require modifying another set of brackets. I figured that the
              GT rears were plenty fine for the 30% left to stop the Avanti. But I wanted
              them to match .. so here are the drilled and slotted rears installed :

              The old rotors :



              Drilled and Slotted rotor installed :



              Caliper back on, with new pads of course :





              Tom
              '63 Avanti R1, '03 Mustang Cobra 13" front disc/98 GT rear brakes, 03 Cobra 17" wheels, GM alt, 97 Z28 leather seats, TKO 5-spd, Ported heads w/SST full flow valves.
              Check out my disc brake adapters to install 1994-2004 Mustang disc brakes on your Studebaker!!
              http://forum.studebakerdriversclub.c...bracket-update
              I have also written many TECH how to articles, do a search for my Forum name to find them

              Comment


              • #8
                Decided since I had the gauge, I might as well check the REAR hubs to be
                sure that they were in spec, I didnt FEEL any noticable pulsing with the old
                rotors, so I though I was safe. Boy was I wrong. I found the pass side hub
                was over .014 out! Thats crazy wobble! I dont know HOW I got away with
                that before. I think it might be because I was using used rotors, and they
                had a slight runout and I was lucky enough to put them on JUST right???

                Regardless, I borrowed a puller, yanked the hubs, & pressed out the new
                studs. These should be EASY to turn on the lathe. This wouldnt have been
                a problem had I just assumed they needed to be "trued". One thing I had
                thought of that could cause the rear to be SO bad. To remove the hubs,
                you must use a puller that pulls on the studs, the amount of force involved
                could warp the hub a couple thousands each time. This slight amount of
                runout probably wont make a difference in a drum brake car, but the max
                runout on a disc is .005, and the bigger the rotor, the larger the error is to
                be exaggerated. Not a big issue to true up with the hub removed, but the
                more material thats removed from the hub surface, the more offcenter the
                rotor becomes comparied to the caliper. The calpiers are sliding, so they
                with self center, but you could remove so much material, as to make the
                caliper bracket interfere with the rotor! (thats a lot of material, but its the
                worst case). To remedy this isnt a hug issue, some .005 shim stock could
                be used between the hub and rotor to recenter. There are always ways to
                get around things that dont go together smoothly (see BFH).

                Tom
                '63 Avanti R1, '03 Mustang Cobra 13" front disc/98 GT rear brakes, 03 Cobra 17" wheels, GM alt, 97 Z28 leather seats, TKO 5-spd, Ported heads w/SST full flow valves.
                Check out my disc brake adapters to install 1994-2004 Mustang disc brakes on your Studebaker!!
                http://forum.studebakerdriversclub.c...bracket-update
                I have also written many TECH how to articles, do a search for my Forum name to find them

                Comment


                • #9
                  Tom,

                  As always great work and thanks for keeping us all updated on the progress with these modifications/upgrades. They sure are looking great!

                  Steve

                  Comment


                  • #10
                    Thanks Steve, but this is a repost (RP) of the archived article, your
                    positive comments are certainly welcome, just clarifying that this is
                    about 2 years ago (not that much else has come about since then). The
                    yer 2008 was a complete waste, as my wifes recovery from surgery and
                    the accident resulting in totalling her car all started the year. My
                    injuries put me behind on the Avanti, and the search for a new car to
                    replace her "baby". Hopefully soon I can refocus on the Avanti and do
                    the Cobra rear brakes to match.

                    Tom
                    '63 Avanti R1, '03 Mustang Cobra 13" front disc/98 GT rear brakes, 03 Cobra 17" wheels, GM alt, 97 Z28 leather seats, TKO 5-spd, Ported heads w/SST full flow valves.
                    Check out my disc brake adapters to install 1994-2004 Mustang disc brakes on your Studebaker!!
                    http://forum.studebakerdriversclub.c...bracket-update
                    I have also written many TECH how to articles, do a search for my Forum name to find them

                    Comment


                    • #11
                      Looks really good Tom.
                      One problem I have run into is pressing the studs out of the old hubs. I found that pressing them out as you show with a very loose pipe, I would sometimes get a slight warp in the hub. I wound up using a tight fitting (around stud head) brass pipe or whatever, allowed me to press them out without any warpage. That might be some of your run-out problem with the rotors. Probably not a bad idea to have the hubs turned for trueness anyway.

                      53commander HDTP
                      53 Champion HDTP
                      64 Champ long bed V8
                      64 Champ long bed V8
                      55/53 Studebaker President S/R
                      53 Hudson Super Wasp Coupe

                      Comment


                      • #12
                        Couple of important tips for you (and others)..

                        (1) [u]NEVER</u> hit a bearing race with a hammer.
                        It is heat treated and can chip a chunk off and that chunk can hit you.
                        (ask me how I know and how many stitches you can get from it[V])
                        Use a flat chunk of mild steel to lay on the bearing race face and hit that instead.

                        (2) Finish modifying your cut race driver, and then turn it around when you use it.
                        In 'finishing it', I mean to heat it up cherry red with a torch and let it cool to room temp by itself (no quenching).
                        This will remove the hardness, and make it less chip prone (safer to use)
                        Then, when you use it to press in the race, turn it around so the race is the same orientation as the one going in (think spoons)..
                        This way, if the outer race tool gets stuck in the hub you can use a long punch to easily tap out the intaller tool because that fat lip will allow the punch tip to hit it.

                        Have done a few thousand that way...
                        HTIH
                        Jeff[8D]




                        http://community.webshots.com/user/deepnhock
                        HTIH (Hope The Info Helps)

                        Jeff


                        Get your facts first, and then you can distort them as much as you please. Mark Twain



                        Note: SDC# 070190 (and earlier...)

                        Comment


                        • #13
                          Thanks Kdancy/Jeff, I havent done thousands and perhaps I have been
                          lucky on the ones I have done, but I am not hitting them very hard.
                          I tap, and move around the race to make sure it goes in straight. If
                          it goes crooked, then it can get stuck and then yah you might have to
                          hit hit harder and that could chip it. Good to clarify. I had the
                          slice taken out of the old race so it cant get stuck, though flipping
                          it over wouldnt hurt - except you are hitting on the smaller end, it
                          could allow it to chip easier. Safety glasses should be worn. The run
                          out that I was seeing was across the hub, I dont see how that could
                          come from using the larger pipe, though it wouldnt hurt to do what you
                          are saying. The distortion (if any resulted) should be localized in
                          the ares of the studs, not a full wheel wobble that I saw. That said,
                          if it only distorted at ONE lug (maybe it required extra force) then I
                          would see it as a full wobble. Both definately worth mentioning.

                          Tom
                          '63 Avanti R1, '03 Mustang Cobra 13" front disc/98 GT rear brakes, 03 Cobra 17" wheels, GM alt, 97 Z28 leather seats, TKO 5-spd, Ported heads w/SST full flow valves.
                          Check out my disc brake adapters to install 1994-2004 Mustang disc brakes on your Studebaker!!
                          http://forum.studebakerdriversclub.c...bracket-update
                          I have also written many TECH how to articles, do a search for my Forum name to find them

                          Comment

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