Unconventional Coaster Brake

I decided to take the coaster brake apart on an old Austrian made Free Spirit. This hub is a bit different from other coaster hubs I've seen, and quite honestly I still don't know exactly how it works (this one is labeled "Styria" on the reaction arm). Anyway, here are the pictures that I took. First I unbolted the reaction arm:

After removing the wheel from the bike, I had to remove the gear from the hub. It's held in place by a snap ring, twist it off with a screwdriver:

Keep track of which order the pieces come apart. With the cog removed I unscrewed the bearing cone by hand, and removed these pieces:

This hub had 5 roller bearings arranged inside a large retaining piece. After unscrewing the lockring that holds the reaction arm to the other side of the hub, I was able to extract these remaining pieces:

The braking mechanism resides inside this splined barrel, which is connected to the reaction arm:

Here is the nearly empty hub shell:

And here is how the inside pieces fit together:

I'm still not sure how everything works, since this isn't like a traditional screw type coaster brake. Regardless, I cleaned the parts up and started reassembling them with lots of grease. First I installed the pieces from the reaction arm side:

Next I replaced the roller bearings:

Then the ball bearings and the axle:

Now I slid the drive mechanism back into place:

And secured it with the bearing cone:

Now the cog can be reinstalled. I lined up the spacers in the order which they came off, then slid the cog into its 3 grooves and locked it in place with the snap ring:

Finally I reinstalled the reaction arm:

Done.

Suicide Brake Levers

Those extension levers that you see on almost every old 10 speed road bike seem to have a bad reputation. I always thought it was because they don't provide as much braking force as the lower brake levers, or maybe it's just because other people think they look stupid. I didn't realize that they might actually be dangerous until I saw this:

That red piece is broken off halfway where the mounting bolt attaches the brake lever to the handlebar. It appears that using the extension piece puts a bending stress on the red cylinder since it attaches to only one side of it. The lower brake lever instead attaches to either end of the cylinder, and in theory it shouldn't put any stress at all on the vulnerable middle part with the hole going though it. Here's the lever put together showing the missing pieces for the extension lever:

In other words, don't rely on the extension pieces in an emergency stop, you're much better off using the lower parts of these brake levers.

Cassette Disassembly

Cassette cogs can be replaced individually if they wear out. Most cassettes are held together with three rivet pins, however. These need to be removed in order to free up the individual cogs. Here's how I do it:

After removing the cassette from the rear wheel, I centerpunch the rivet heads (so that the drill doesn't wander around). Next I drill each rivet until most of the rivet head has been removed. Next I take my drift punch and hammer the rivets out part way:

You can use something like a long nail if you don't have a punch. Anyway, once these pins are broken loose you can pull them out from the back side with pliers:

All done:

Don't lose the cogs or spacers if you plan to reuse them. The pins are not essential and shouldn't be reinstalled (the cassette lockring will hold everything in place). Also if you're replacing individual cogs, try to get replacements from the same cassette group (Shimano cassettes have their group designation stamped on each cog, like ac, e, w, etc.). If you use mismatched hyperglide cogs, the shifting might be noticeably worse on those cogs. This method doesn't apply to high end cassettes like Ultegra or Dura-Ace though, since the cogs are mounted to aluminum carriers and aren't individually replaceable.

Freehub Body Removal

Cassette hubs usually have a removable freehub body. There are a few instances when you might need to remove or replace one, so I'll show you how. First remove the axle and ball bearings (described here). Next you'll need either a long arm allen key or a hex socket bit (10mm for Shimano hubs):

Stick the tool into the freehub and unscrew it counterclockwise. These can be on there pretty tight, so don't be surprised. Once it's broken loose, remove the hollow bolt and the freehub body together:

Here is the bare hub shell, showing the splines that transfer your pedaling force to the wheel:

And here are all the pieces that you removed from the wheel:

The hub goes back together the same way you took it apart. This is a good time to clean the bearings and reassemble them with fresh grease. You might want to replace your freehub body if you try to pedal forward and your pedals just spin without turning the wheel. You would also want to replace it if you upgrade an old 7 speed bike to 8, 9, or 10 speed, since newer cassettes don't entirely fit on shorter 7 speed freehub bodies.

Polishing Metal Parts

Bare aluminum brakes, seatposts, handlebars, stems, cranks, etc. tend to look a but dull over the years. You can make them look close to new again with some polish. Here's an old aluminum brake that I took apart a long time ago:

It looks a bit dull so I thought I'd use it to show how I polish metal parts. First I rub a thin layer of polishing cream onto the surface:

Then I use a small towel to rub the polish into the surface. I stop when I see a black film appear:

 

The last step is to buff the part with a clean, soft towel:

All done:

The difference is more noticeable in real life, but you get the idea.