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  •  » Cobra Disc Issue

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    12/13/2016 8:56 PM  #1

    Chaplin
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    Registered: 3/14/2015
    Posts: 1,027

    Cobra Disc Issue

    Wondering if anyone else has run into this.  I finally installed the front Cobra conversion brackets that I got from Steve on my 64.5 vert.  The conversion brackets fit great and went on without an issue.  I bolted the caliper brackets on and dropped the calipers in and then proceeded to install the pins that lock the calipers in place.  The passenger side went in easily and the rotor spun freely.  The pin on the driver's side was a snugger fit, but finally went in except that when I went to spun the rotor, the edge of the rotor was lightly rubbing against the pin.  As I continued to try and spin the rotor, it got to the point where it got so tight against the pin that it would lock up.  Upon visual inspection (no actual precise measuring tools were harmed during this experiment), it looked like the rotor itself was a little out of round because one side cleared the pin completely but the other side would hit the pin.   

    The rotors are Stoptech slotted rotors that I got from Rock Auto or Summit (can't remember right now).

    I've got another caliper and another caliper mounting bracket that I can swap out and see if it makes a difference, but I ran out of time to continue playing with it tonight, but will try that tomorrow.

    Anyone else experience this?

     

    12/13/2016 9:30 PM  #2

    josh-kebob
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    From: Madison, AL
    Registered: 4/06/2013
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    Re: Cobra Disc Issue

    No experience like that but, you could always swap the passenger side rotor over the DS and see if you have the same issue. If there's no issue, then I'd say the one rotor is warped. 

     

    12/13/2016 9:44 PM  #3

    Chaplin
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    Re: Cobra Disc Issue

    Thanks, I will try swapping the rotors too and see if that makes a difference.

       •Thread Starter
     

    12/13/2016 9:57 PM  #4

    MS
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    From: Canyon Lake, Texas
    Registered: 1/24/2013
    Posts: 12,688

    Re: Cobra Disc Issue

    I have run across some cobra rotors that are a tiny bit larger than stock. Also, be sure you are using the centering rings supplied.  You can also loosen the caliper mounting bolts and pull outward on the caliper and retighten. That might get you a tiny bit of extra clearance. You can do the same where the two conversion brackets bolt together.  You are dealing with three precisely located sets of holes, but each hole has to be a tiny bit larger than the fastener. All those tolerances can shift things slightly.
    Do you have the rotor bolted tight onto the hub while doing this?

    Money you enjoy wasting is NOT wasted money... unless your wife finds out.
     

    12/13/2016 10:32 PM  #5

    Chaplin
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    Re: Cobra Disc Issue

    Thanks.  I had already loctited the bolts for the conversion brackets in place, so I didn't try to adjust those at all, but I did loosen the caliper bracket mounting bolts to try and move the caliper bracket around a little bit and that did provide a little extra room, but not enough.  I ran three lug nuts down ( at 12 o'clock, 5 o'clock and 7 o'clock) to snug the rotor down. I am using the supplied centering rings. 

    I'll swap the rotors from side to side tomorrow and also try swapping the caliper mounting brackets and see if that makes a difference. 

    Stay tuned...

       •Thread Starter
     

    12/14/2016 9:42 AM  #6

    blueoval50
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    Registered: 6/09/2015
    Posts: 21

    Re: Cobra Disc Issue

    I ran into a similar issue on my 66. It took completely tightening all the lug nuts down to remove any runout that measured at the rotor. I believe my issue was due to slightly distorted hubs from pressing new studs. Hope this helps.

     

    12/14/2016 1:53 PM  #7

    MS
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    From: Canyon Lake, Texas
    Registered: 1/24/2013
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    Re: Cobra Disc Issue

    The brackets were designed to place the caliper as far down on the rotor as possible (and still clear, of course) so that it would provide the maximum clearance for wheels used on the early cars.  Sorry you are having problems, but it must be rotor OD related.

    Money you enjoy wasting is NOT wasted money... unless your wife finds out.
     

    12/14/2016 3:35 PM  #8

    Chaplin
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    Re: Cobra Disc Issue

    I'm very impressed with the brackets and how well they fit. It's almost like they were designed for the car!  LOL  

    I am quite certain it is a problem with the rotor itself, as the passenger side is perfect.  I'll do some rotor and caliper bracket swapping tonight and report back. I'll also torque all 5 lug nuts down and see if that changes anything.  

       •Thread Starter
     

    12/14/2016 7:47 PM  #9

    Chaplin
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    Re: Cobra Disc Issue

    Well, I was wrong, it's not a rotor issue.  It turns out it's a caliper bracket issue.  I swapped out the bracket that came with the caliper for another bracket that I had and there is no interference at all with the rotor/pin.  The caliper brackets should be identical (same part numbers), but on the one causing the problem it is almost like they cut the groove that the pin sits in too shallow or too close to the rotor because if I leave the caliper out and try to slide the pin in through that groove, it hits the rotor.  If I do the same thing with the spare caliper bracket, the pin lays down in the groove and is kept well away from the edge of the rotor. I wouldn't have expected there to be that much variance in the manufacturing of the brackets, but I guess there is.

       •Thread Starter
     

     

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