Drum Brake Renovation

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.

Comparison between customised bolt with Seeger clip ring (left) vs original Starlock ring.

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… 😉

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7 Responses to Drum Brake Renovation

  1. Tony Grant says:

    How far can you go with a set of brake pads Marc? I understand that you are probably wearing them faster because of the speeds you ride at, my problem will be (my trike will be delivered next week… 🙂 ) hills a.k.a. Pyrenees.

    • Marc says:

      Not to forget the 24″ wheels. They probably cost some ‘brake life’ too.

      A set of 90mm drum brakes plates lastet around 8,000km between changes (three sets so far). I’ve simply bought new brake plates (€60 a set), since new brake pads are only marginally cheaper and you get the whole brake mechanism with the brake plates.

      When renovating the brakes yesterday, I had a good look at the old, discarded brake plate sets. The brake pads are actually not that much worn (87.5mm diameter). If I use 0.5mm shims, to bring the brake pad diameter back to ‘new’ spec (ca 88,5mm) and give them a thorough clean and lube job, they will probably last an other 5,000-6,000km.

  2. daytriker says:

    So if I read your information correctly, the service life of the brake pads is only 1mm of wear before they would normally be replaced? Are you sure there isn’t take up adjustment to account for that? It seems very minimal wear.

    • Marc says:

      I’ve probably discarded the old brake plates a bit too early. They are used year round on commuter duty and when they started acting-up, I’ve simply replaced them.
      However, there is not much wear left on them in their current state (without shims). While there is plenty of actual brake pad left, at a certain angle of the brake lever, the brake pad spring has some trouble to move the brake lever back and the brakes seize-up after hard braking. Very annoing in traffic if you have to push the brake lever back by hand to get rolling again.

  3. Tony Grant says:

    I am going to put 24″ rims on the front, you sold me that idea 🙂

    • Marc says:

      Cool! I wanna see pictures!

      • Tony Grant says:

        You will have to wait a bit, I measured and 24″ prevents me from keeping the folded trike at the bottom of the stairs 🤔 I am looking for a new apartment anyway. Loving riding bent, thanks for the inspiration Marc! Can’t wait to get the motor fitted but taking my time to learn first.

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