Thread: How do you determine who's disc brake conversion you have?

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Strange axles and possibly whole rear end housing-call them!!!!!!!!!

".......what you have looks like Ford rotor that started out as a 5 on 5" bolt circle......"


If you look at the first picture in post 11, it sure looks like a Ford logo and part number above the tape measurer......the basis for my comment above.


As far as weakening the rotor there is a fair amount of meat there and the rotors that you have were obviously good enough to wear out without failing.

"..............I'd be less concerned with the weakened rotor as I would to getting the holes perfect and concentric.......If you have a good quality drill press, precision center punches, and a precision alignment jig (just a cylinder to slide into the centers) then I'd say go for it......."


Sometimes it's too easy to over think things Firebird.

Assuming the worn out rotor was drilled correctly in the first place and the new (undrilled) rotor is also correct it should be fine. Keep in mind that the rotor in NOT centered on the studs. Removable rotors and brake drums are centered on the axle hub which has a lot closer tolerance than the stud holes which usually have a fair amount of tolerance (slop) built into to them.

As long as you keep the hub holes centered (which is critical) the stud holes will fall where they belong. As the stud holes are really not that critical I personally would not be afraid to drill them with a hand drill if I had too......although I would most likely use my drill press



.

Thanks for the clarification.

Look up 1978 Lincoln Mk3 rear brakes--------


I have been trying to copy stuff but hasn't worked-------

Forget the Versaille? parts as that isn't what this rear is---look up the Mark 3, Makk 5-they have 11.5 rotors---------------

good luck----

Originally Posted by jerry clayton

Strange axles and possibly whole rear end housing-call them!!!!!!!!!

Already called them many times and no joy. They say axles are theirs but nothing else.

So I found a rotor on Oreilly's and Raybestos #96586 that may just work with all the right dims. 1997 Jaguar XJ6. If this don't work I'll buy the suggested lincoln Mark V's and drill them to 4.75"

Rotor Casting Type Vented
Rotor Outer Diameter (IN) 11.460
Discard Thickness (IN) 1.063
Nominal Thickness (in) 1.110
Rotor Type Conventional
Overall Height (in) 2.635
Surface Finish Plain
Wheel Bolt Circle Diameter (IN) 4.750
Number of Bolt Holes 5

Ford did own Jaguar for a time. So perhaps that is possible.

I wish I could of loaded the pics/specs of the Lincoln -------it was the parts you need----------hub size, rotor thickness, offset--I even found them available at the autozone in your town in Fla

Originally Posted by jerry clayton

I wish I could of loaded the pics/specs of the Lincoln -------it was the parts you need----------hub size, rotor thickness, offset--I even found them available at the autozone in your town in Fla

Couldn't you just copy and paste the link or give him the part number?

They received the Jaguar rotors and they were as close as I am going to get but NO cigar. All dimensions were the same except the rotor inner dimension. The Strange Axle has a 6 1/4 inch diameter face and the inside diameter on the Jaguar rotor is 6 1/8 inch. A lousy 1/8th of an inch!

Back to square one.

At this point your options are limited. If you want to keep the current brakes, you're going to have to get the MK3 rotors and redrill them. I would bet that is what you have now with the worn out ones. Redrilling rotors is very common in hot rodding and it's not unusual to see aftermarket brake setups with multiple bolt patterns on the same rotor.

Or, you could contact Wilwood. They offer 2 piece rotors where the cast iron rotor attaches to a separate hat section. The hats are available in various offsets, bores and bolt patterns. The rotors are available in several sizes and thicknesses. They might be able to come up with a combo that will fit your application, but these rotors are not cheap by a long shot.

Or, you can take the Jag ones and have them bored out to fit the Strange axles. Or, you can have the Strange axles turned down to fit the Jag rotors.

Or, you could ditch the old MK3 brakes and buy a completely new rear brake setup. Those appear to be the Torino big bearing ends on the housing, so there should be a bunch of options available from several suppliers due to the popularity of the 9" in the hot rod world.

Of all these options, redrilling is going to be the cheapest, easiest and fastest solution.

FWIW - What you were told about the rotors being hubcentric and not relying on the bolt pattern to centralize them is 100% correct. The last rotors I redrilled actually had 17/32" hole in them from the factory. That's 1/32" larger than the 1/2" stud. At that rate, using the old rotors as a guide and just lining the center bore up will get you plenty close enough. As long as the center bore fits snug over hub and the studs go though the holes, you're good.

Or pop the axles, run'em to a machine shop (or see a friend with a lathe) and turn the od down the 1/8 +.005 or 6.... easy peasy..

".........Or pop the axles, run'em to a machine shop (or see a friend with a lathe) and turn the od down the 1/8 +.005 or 6.... easy peasy......."


That would probably be the solution I'd go with. Rotors are a wear part, and generally speaking axles aren't, meaning the next time you need rotors it's just a trip to the parts store instead of going thru all this again.

Personally I'd go with a lot more clearance between the axle and inside of the rotor, Remember the inside of the rotor is open to the elements and will be subjected to rust and crud build up (check and get an idea of what you currently have for clearance with the current axle and rotor). You don't want to spend half a day fighting the rotors off the car.




Ok this is a little off topic

On a side note Mike did a good job outlining out your options. There is one more however. I built an 83 El Camino several years ago that was always intended for and got used as a daily driver/long distance cruiser (it's made 7 or 8 4000 mile round trip drives back to Illinois). I built a 9" ford rear end for it that resulted in having a 5 on 4 3/4" bolt circle in the front and 5 on 4 1/2" in the rear. Rather than re-drilling rotors or rear axles/drums, as it turned out the wheels I wanted to run (Corvette Rallys) were available with dual bolt pattern.

https://www.speedwaymotors.com/Speed...ern,70840.html

Yeah yeah I know on the surface it sounds like a cheap Mickey Mouse solution The reason I went this route was primarily for the long trips. Should it ever happen that I had to change an axle/drum/rotor (depending on what I had redrilled) in a strange town somewhere between AZ and IL I would not have to find a machine shop to "customize" a replacement part.

At the price of the wheels I was a little leery of the quality when I ordered them. The ones I got are made of nice thick steel and I checked for runout on all 5 and there were as good as most stock OE wheels. Also by the time you add beauty rings and caps they ain't that cheap.

OK I'm done rambling on.




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Originally Posted by Hotrod46

FWIW - What you were told about the rotors being hubcentric and not relying on the bolt pattern to centralize them is 100% correct. The last rotors I redrilled actually had 17/32" hole in them from the factory. That's 1/32" larger than the 1/2" stud. At that rate, using the old rotors as a guide and just lining the center bore up will get you plenty close enough. As long as the center bore fits snug over hub and the studs go though the holes, you're good.

I bought the 78 Lincoln Mark V rotors with 5 x 5" pattern. I bolted them hat to hat and used the old rotors as a guide. Studs on axles are 1/2 x 20 so I drilled the holes using a 9/16ths bit. All done and mounting them now. Writing it down for future reference.