The drum brakes on the Blue ICE started acting up after a mere 8.650km of heavy use.
Braking performance was still good, but the left brake was starting to get stuck. That’s normally a sure sign that the brake pads are at the end of their life. If this happens, you can extend their service life by putting some shims under the little hardened steel ‘shoes’ that sit between the brake pads and the brake lever shaft (see image 2).
Since both of my prefered ‘drum brake vendors’ where closed for Summer holidays, I’ve cannibalized the new brake plates from the Black ICE (at this rate, the Black ICE is probably back on the road in Summer 2047 *sigh*).
Yesterday, I took a closer look at the old brakes. Since I’ve already put 0.5mm shims into the ‘brake shoes’ some 2,500km ago, I didn’t have high hopes, though.
As it turned out, the brake pad diameter was still quite similar to new (88.5mm) and they only needed a thorough cleaning and lubrication.
This is when you run into some trouble with the Sturmey Archer drum brakes. They (understandably) choose easy production and assembly over maintainance when they used these Starlock lock rings on the axles. They are virtually impossible to remove undamaged and the big one for the 11mm diameter bolt are pretty hard to come by.
I had some Seeger clip rings and a couple of 0.1mm shim rings at hand. The only thing missing was a notch for the clip ring in one of the bolts. A metal saw fixed the missing notches. I’ve used a couple of 12mm washers as guide to saw the notch around the bolt. The shim rings allowed to adjust the axial play of the brake pads on the bolt.
I’ve put the brakes back into the trike and did an extended test ride. All good and the brakes feel like new again.
Update August 27, 2017:
The renovated brakes don’t play ball. They do brake, but the hand force necessary to make them behave is quite high after about 100km. While its normal that they need a new braking-in period to settle, the dust that’s wearing-off the brake pads shouldn’t stick to them. I cleaned the brake pads with brake cleaner, maybe that’s the problem (that didn’t work too well before, but I forgot).
Today I’ve used acetone for cleaning. Lets hope that’s working better…
Update September 2, 2017
Cleaning the brake pads with acetone did the trick.
Note to self: Never use brake cleaner again!
Now, I’m thinking about water-cooled drum brakes. Stay tuned… 😉