Drilling the brake drums

[bighammer]

Why couldn't this be done, I remember somebody doing this years ago. Could the SBP drums be drilled for BBP in order to be able to switch to 15 inch rims?

Thanks

 

[1968FormulaS340]

Well, it takes more than drilling the drums (which I don't recommend).

You need to change the pattern of the studs. This requires a hub and/or axle change (and other assorted parts). Some people re-drill their axles (again, not something I would do, although it's probably fine).

 

[aengineguy]

Well, it takes more than drilling the drums (which I don't recommend).

You need to change the pattern of the studs. This requires a hub and/or axle change (and other assorted parts). Some people re-drill their axles (again, not something I would do, although it's probably fine).

x2 here. Have a 71 Swinger. On the rear I installed some Moser axles with large bolt pattern. The front...new Wilwoods, so no problems. Although I did redrill my original drums, have had no issues. If you clock the drums so that the new pattern is in between the old, there is plenty of meat there. The rub is that the old drums probably are a little weak from fatigue after a lot of years. Eventually I am going to discs on the back.

 

[Charrlie_S]

My 66 Cuda has an "A" body 8 3/4 rear. I drilled a set of axles for the BBP and drilled my drums. I can run a 3.91 gear and tall(er) tires (15 inch BBP wheels) for the 1/4 mile, then just change the axles to the small bolt pattern and use a short 13 inch wheel/tire for the 1/8 mile. Don't have to touch the brakes, at all, since the drums are reinstalled as they came off. A lot easier then swapping chunks. If redrilling the axles, I don't recommend press in studs (not a lot of metal in the flange) use half inch threaded studs.

 

[Buschi340]

x2 here. Have a 71 Swinger. On the rear I installed some Moser axles with large bolt pattern. The front...new Wilwoods, so no problems. Although I did redrill my original drums, have had no issues. If you clock the drums so that the new pattern is in between the old, there is plenty of meat there. The rub is that the old drums probably are a little weak from fatigue after a lot of years. Eventually I am going to discs on the back.

I did exactly the same on the rear. With Yukon axles. The obening for the hub, if I remember right, had to widen a bit as well

 

[Oldmanmopar]

The taper on a SB drum prevents themfrom sitting flush on the flange on a BB axle. We convert SB to BB here all the time using a fixture on a mill with a indexer. Threaded studs must be used.

 

[Charrlie_S]

The taper on a SB drum prevents themfrom sitting flush on the flange on a BB axle. We convert SB to BB here all the time using a fixture on a mill with a indexer. Threaded studs must be used.

Yep, That's what I do, however I don't have an "indexer", I have a drill fixture, with hardened drill bushings, that I fasten to the axle flange, and use a drill press. The fixture was made on a "jig bore" machine, when I worked as a machinest, about 30 years ago.