I have a 11”x 3” rear drum that we purchased from Freman’s Auto Wreaking in Whitehall, Montana over 25 years ago. We intended to use it on our son’s 1963 New Yorker with heavy duty suspension, but never used it. Sold the 1963 without giving the new owner the drum.
I would be willing to sell it. It is in very good condition.
I cannot help you with a source for drums, but I do want to point out how to distinguish an 11 x 2-1/2 inch drum from an 11 x 3 inch drum visually. The width of the machined surface (inside to outside) is different between the two drums, but the actual width measurement could cause confusion if you are not fully educated. The machined surface of the 11 x 2-1/2 inch drum is 3 inches deep. The machined surface of the 11 x 3 inch drum is 3-1/2 inches deep.
In 1963 & 1964 the 11 x 3 inch rear brakes were installed only on 300's (sport & letter) with the heavy duty suspension option and station wagons. The 11 x 3 inch rear brake assembly uses a special backing plate that is recessed 1/2 inch into the car, the 3-1/2 inch wide drum, and 3-inch wide brake shoes that interchange with the front brakes. Likewise, the 11 x 2-1/2 inch rear brake assembly uses a standard backing plate with a 3 inch deep drum. When each size brake assembly is assembled with the proper width brake shoes, the shoes are centered on the machine surface and contact the drum with a 1/4 inch gap of non-contacted machine surface on either side of the shoes.
Problems can occur if the wrong width shoe is installed in either assembly. Either width shoes will mount correctly to either style backing plate. If 3 inch wide shoes are installed inside a 2-1/2 inch brake assembly, the drum may not fit correctly or there could be rubbing of the metal portion of the shoe against the inside surface of the drum. On the other hand, if 2-1/2 inch wide shoes are mounted in a 3 inch brake assembly, the drum will mount perfectly, but there will be a 1/2 inch gap of non-contacted drum surface inside the drum and the shoe will have full contact to the inner edge of the drum machined surface.
This topic came up a few years ago between me and Rich Barber when he discovered 2-1/2 wide shoes in the 3 inch brake assemblies in his ram K convertible. When I removed the drums on my K hardtop with heavy duty suspension option, I, too, discovered 2-1/2 inch shoes in the 3 inch brake assemblies. Needless to say, proper shoes have now been installed on both cars.
I hope information will be helpful to you and others going forward.
Chris the K MANIAC
My first ’63 Chrysler conv 300 had rear brakes that had the hub attached with key slot. After quite a bit of effort, I was able to remove the brake drums with hubs.
These rear drums (11x3) are becoming hard to find that have any metal left.
My current ’63 300 conv has rear drums that slide off and the hubs remain on the vehicle I believe some modification by grinding was done before I got it to loosen the drums from the hubs.
Question: Does anyone know if there is a generic Mopar or other model (11x3) drum that would fit over the existing hub?
This set up certainly makes it easier to access the brakes.
Posted by: "John L. Chesnutt" <chesnutt@xxxxxxxxxxxx>
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