Tandem Cycling - Arai drum brake - loose brake plate

I'm having trouble with the rear wheel and wondering if the Arai drum brake is installed correctly. The brake plate is sitting on a couple loose washers over the drum. The diameter of the axle must be 3-4 mm smaller than the diameter of the hole in the brake plate. The brake plate just sits in there with no bearings while the axle spins. When the spacer on the axle is pushed in tight on the brake plate, I can still push in the edge of the brake plate, and it moves, oh, 2-5 mm. Seems really loose. Does this installation sound correct?

The trouble I'm having with the rear wheel is that when we stop pedaling the tandem, the free hub does not engage so the top part of the chain gets a lot of slack. This started to happen about 10 days of riding after I had the rear wheel rebuilt with a new rim (due to a damaged rim). My guess is the problem is probably on the free hub/cassette side, but it could be the drum brake maybe?

Bryan

I don't have ours in front of me but working from memory, there should be some spacers (washers) that take up the space between the axle nut and the brake shoe plate.

What is often done is to lightly snug to brake shoe plate to the axle and they actuate the brake lever. This will equalize the space between each shoe and the drum. Then, tighten the brake shoe plate fully. If you are not able to tighten the brake shoe plate to the axle, you must be missing a spacer or two.

What is often done is to lightly snug to brake shoe plate to the axle and they actuate the brake lever. This will equalize the space between each shoe and the drum. Then, tighten the brake shoe plate fully. If you are not able to tighten the brake shoe plate to the axle, you must be missing a spacer or two.

That makes sense. What about the different diameters of the axle and the hole in the brake shoe plate? Is the only reason it doesn't move around because the brake shoe plate sets in the outer part of the brake?

I don't have mine in front of me either so I'm going from memory. It's at the shop where they're replacing a spoke.

That makes sense. What about the different diameters of the axle and the hole in the brake shoe plate?

As I recall, there are different size Arai drum brakes for different size axles; the axle and hole should be closely matched in size. I've reamed out a smaller drum to fit on a new rear hub with larger axle but I'm not sure there's a practical way to put material back in a drum plate where the hole is too big.