I have been working on a 26" folding MTB, and its coming together slowly. The rear wheel has a band brake and for the life of me I can't get it to work well.
I have no experience with this kind of brake. Nearest I've worked with is a drum brake on a tandem, and drum brakes on a car.
Band side of brake. When actuated, the silver lever on the upper left rotates, and the band is pulled up and right. Since the other end is fixed by the rusty rivet, the band has to take a shorter path and decreases in circumference thereby tightening on the drum.
So when braking under no-load this brake works perfectly and stops the suspended rear wheel quickly. When riding, this brake has a barely-perceptible slowing effect, and absolutely nothing if its a downhill grade in any way.
I have tried a light sand of the drum to remove any glaze. I've also sanded the band lightly but its soft so didn't want to tear it.
Also I've applied an electrical cleaner spray called Contact60 That also made no difference to braking. The band appears to absorb the spray
So far I have not applied "brakleen" because the band is soft and am worried about it absorbing into the band, rendering it contaminated permanently.
What else can I do to improve this brake? Or should I simply replace the whole thing with a conventional rim brake ?