Are certain drums not compatible with electric brakes?

[mylesm260]

Just finished installing a shark skin electric brake kit.

Single axel, 3500#

The kit came with the back plates, all the wires, the break-away kit and the battery.

I verified that the magnets were getting power, I had someone engage the brake controller in the truck, and the magnets attracted a wrench.

I also adjusted the brakes properly after installing them (tighten down then back off a bit so the drum can spin)

But, the brakes are NOT working. I suspect this is because my old drums do not have the correct offset and machined surface for the magnets to grab on to.

Is this correct? do certain drums not work with electric brakes?

 

[Titanium48]

Re: Are certain drums not compatible with electric brakes?

It could be the problem. Drums for electric brakes have two machined surfaces - one around the outside for the shoes, and one on the inner face near the studs for the magnets to stick to. The rotating drum drags the magnet along, which in turn pulls the magnet arm and forces the shoes against the outer surface.