I was recently told by a fellow 56 Olds owner that he had HEARD that '71 Chevy Truck drums fit 56 Olds rear... Both are 11" by 2" with a 5 on 5 bolt pattern.

Has anyone tried this or can anyone tell me why these would not work? The price is substantially less and I just cant see any reason they wouldnt. However I dont want to find out the hard way that they would for some reason.

Thanks,
Rick

 

No shot.........

 

There are several critical dimensions that need to be compared. The first is the depth from the inside face of the drum (where it sits against the axle flange) to the edge of the drum where it would rub on the backing plate. The second is the location of the friction surface inboard from this same inside face of the drum.

As an example of why this is critical, I also tried to get away from the expensive original drums on my 67 Delta 88. I have a pair of drums from a 1984 Custom Cruiser. Same 11x2 brakes, same 5 x 5" bolt pattern. Unfortunately, the axle flange on the newer car sits further outboard from the backing plate. When I tried the newer drums on my 67, the rim of the drum hit the backing plate. You'd need to machine off at least 1/4" to clear.

I'll also suggest that the Chinesium drums sold by many suppliers today LOOK like those newer drums and it's entirely possible that vendors are buying the new ones and machining them as I suggested. These drums don't look anything like the originals. They may work just fine on a lightly-driven show car, but I'm not sure how they'd hold up to regular use. I've also had very bad luck with brand new Chinesium drums being out of round when you take them out of the box.

An OEM drum or N.O.S. replacement is your best bet if you can find one. If not, you'll need to do the best you can with replacement parts.

 

1952-56 & part '57 Oldsmobile; 561761; 565964