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Rear disc brakes on flanged axle

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  • Rear disc brakes on flanged axle

    My sons and I have been rebuilding a 54 Champion sedan. We installed a set of Phil Harris' flanged axles in the Dana 44 TT rear end. We also put a set of Steeltech's large disc brakes on the front, and Jim Turner's disc brakes on the rear. The question I have is that the interior diameter of the rear rotors is larger than the central hub, and the lug bolt holes are drilled a little bigger than the bolts. As a result the rotors aren't exactly centered, close but depending on how they sit when the rim bolts on, they could be out by 1/8" or so. Is this a problem? I tried to call Jim Turner but of course it's the long weekend. I thought someone on the forum might have some insight.

    Thanks,

    John

    John
    1953 Commander Coupe
    1954 Champion Sedan
    1963 Lark

    John
    1953 Commander Coupe
    1954 Champion Sedan
    1963 Lark

  • #2
    Worst case scenario; it's going to be out of balance and cause vibration, plus it could chew up your pads when the edge of the rotor scrapes against them. I would cut a sliver of sheet metal to wrap around the hub to center the rotor.

    Comment


    • #3
      quote:Originally posted by buddymander

      Worst case scenario; it's going to be out of balance and cause vibration, plus it could chew up your pads when the edge of the rotor scrapes against them. I would cut a sliver of sheet metal to wrap around the hub to center the rotor.
      I would probably call Jim, explain the situation and see about a replacement. As mentioned, an offset rotor will create vibration issues.

      ---------------------------------------------------------------------------------------------------
      Tom - Mulberry, FL

      1964 Studebaker Daytona - 289 4V, 4-Speed (Cost To Date: $2125.60)

      Tom - Bradenton, FL

      1964 Studebaker Daytona - 289 4V, 4-Speed (Cost To Date: $2514.10)
      1964 Studebaker Commander - 170 1V, 3-Speed w/OD

      Comment


      • #4
        quote:Originally posted by buddymander

        Worst case scenario; it's going to be out of balance and cause vibration, plus it could chew up your pads when the edge of the rotor scrapes against them. I would cut a sliver of sheet metal to wrap around the hub to center the rotor.
        You could always pull the axles, drive out the studs, ream them oversize and drive in new ones with the correct "shoulder" for the rotors you have. Seems to me this would be a WAY better solution than a band of sheet metal!

        Comment


        • #5
          Well, ya can't just grab any old piece of sheet metal; it has to be the correct thickness. It has to be thin enough to go all the way around the hub, but thick enough to take up all of the slack. I've done things like that and always get them within a few thousandths. Measure the clearance with a wire gauge and use sheet metal half that distance in thickness. You cant get ANY closer than that.

          Comment


          • #6
            I have the same stuff to do the same installation so I'm very interested in the solution. That rotor should sit nice and snug on the hub. You could get crazy and center it with a cone of sorts then drill the rotor and flange together, thread the flange, countersink the hole in the rotor and with a couple of proper screws bolt them together.



            Comment


            • #7
              This is how I did it guys.These are out of secquence. had to pull wheels and take pictures for you to see,
              This is the finished rotor. But I'll start here.

              With the rotor off.scribe a line to the out side of the lugs.You can just see mine.Find the center between them. should be about 1.04" Mark and drill three 1/4" holes.NOTE a letter F drill should be used to tap 5/16NC holes.)but not every one has a set of these.(I used 5/16"NC flat head allens. you can drill five. just more work.


              Your disk may or may nor have been counter sunk at the stud holes.
              You can use the lug nuts to center the rotor. You can use all five ,but three will work.
              Now you can transfer the holes using the rotor as a guide.Remove the rotor and tap the holes.This is where the it get a little tougher. These Axels are hard!Use plenty of tapping fluid and go slow.
              With the rotor off. You can now counter sink the holes.I used a 3/4"45degree This can be done with a hand drill. but the drill press will make it easier.


              This what it will look like when your done.
              If you have any questions . just ask. I can pull the whees and mock up any step. and take a picture of it.


              Comment


              • #8
                That looks alot harder than just using lug studs with the right sized "shoulder." But I'm sure it will work OK.

                Comment


                • #9
                  I believe that the Fairborn axles come with a "centering ring" to center the drums on the new hubs, as the hub on the new axles is in fact smaller than the old Stude drums. If I understand your issue correctly, your problem is that the hole in the discs is a different size yet so the Fairborn centering ring will not work. I would probably have a new centering ring made, and depending on how often you plan on having the discs off and on, either secure the new ring to the axle flange (this would allow for easy disc R&R and replacement but would require that two rings be made) or else use the centering ring to center the disc and then drill the disc and flange for retaining screws a la BMW, Porsche, VW, etc. but this would require precisely redrilling any replacement discs. I agree I would use countersunk phillips or (preferably) allen, Torx, or triple-square head bolts to fasten the centering rings to the axle flange.

                  I think if I were to order a pair of Fairborn axles I might buy an extra centering ring from them so it could be permanently fastened to the axle flange as I describe above just to make maintenance easier and the drum/disc placement more permanent and secure, even if I were sticking with rear drum brakes.

                  nate

                  --
                  55 Commander Starlight
                  http://members.cox.net/njnagel
                  --
                  55 Commander Starlight
                  http://members.cox.net/njnagel

                  Comment


                  • #10
                    Thanks for all the comments.

                    Jim Turner sent me an email in which he said "To answer your question, the rotors should center on the studs after slight rotation."

                    I then spoke to Phil Harris. Phil confirmed that others have noticed that the rotors aren't necessarily centered on the hubs, but in fact it is not a problem. The rotors center themselves the first hard braking. Phil acknowledges that all the OEM set-ups have centered rotors, but he can't recall anyone ever having a problem from this. Phil suggested that I put the rims on the rear with the lug nuts not super tight, then do the hard braking, and then put a heavier torque on the nuts.

                    If you think about it, this makes sense to me. When the caliper grabs the rotor, the forward momentum of the lug bolts will tend to force them against the 3 o'clock position in each lug bolt hole in the rotor, so the rotor will be forced to center on the hub. Each lug bolt will not be centered in its hole, but will be against the 3 o'clock position in the hole. On acceleration the rotors are just along for the ride, so nothing will change. I guess heavy reverse braking (which doesn't happen often) might force the lug bolts against the 9 o'clock position in the holes, but this won't change the fact that the rotors are centered.

                    So before I try any of the fixes suggested, I think I'll drive the car (in a parking lot!), do some hard braking and see if in fact there is a problem.

                    By the way, the ring provided by Phil on his Fairborn flanged axles is too skinny to mill down to center the rotors. There is a 1/8" or so taper on the hub hole at the backside of the rotor, so you would need quite a thick sleeve around the hub to center the rotor on.

                    Thanks again,

                    John

                    John
                    1953 Commander Coupe
                    1954 Champion Sedan
                    1963 Lark

                    John
                    1953 Commander Coupe
                    1954 Champion Sedan
                    1963 Lark

                    Comment


                    • #11
                      That's a relief...thanks for update post

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                      • #12
                        A centering ring..hmm. is that a lot like a piece of thick sheet metal curved around into a circle? Why didn't I think of that.

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                        • #13
                          Another idea I just thought of that might be more elegant - have a machine shop drill new lug holes in the rotors to be a tight fit on the Fairborn axles, halfway between each of the existing ones.

                          nate

                          --
                          55 Commander Starlight
                          http://members.cox.net/njnagel
                          --
                          55 Commander Starlight
                          http://members.cox.net/njnagel

                          Comment


                          • #14
                            I have a pair of 2007 Chrysler rotors which fit the Studebaker hub and wheel lug circle just fine, except that the holes for the studs are bigger than the studs, just like the op's. I figured that you could prolly find a piece of tubing or ound bar stock, and have a machine shop make you a set of snug-fitting spacer rings that will be captive when you install the wheel onto the rotor and hub. The thing about leaving it loose, so it finds the "3 oclock" position(and then tightening it) is this--I am afraid the inertia difference from braking, accelerating and decelerating over timewill overcome the clamping force of the wheel lugs, and cause the holes to elongate to the point where there will be a problem.. I've seen this with wheels and wheel studs, and also from undertorqued flywheel bolts. Always better to overengineer it a bit, for safety's sake..

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                            • #15
                              Like I said before. YOU CAN BUY NEW STUDS WITH A WIDER SHOULDER. Buy 10 new studs for about $25, drive out the studs in the axle, ream the holes to fit the new studs WITH THE PROPER SHOULDER FOR YOUR ROTORS and drive in the new studs. This is by FAR the most elegant way to solve the problem and also THE EASIEST!



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