A Nurse with a Gun

Sunday, August 10, 2008

Coaster Brake Rebuild/Repair

I was up until three AM last night rebuilding the rear hub/coaster brake on the Raleigh PUB. The house is quieter, allowing me to think things through at that hour. Since the rear wheel was perfectly true, I did not want to remove the hub and then have to lace it up again. I decided to rebuild the hub inside the wheel.

I followed Steve Litt's disassembly instructions, cleaned the parts in brake cleaner, Click to enlargeand did my troubleshooting. The first problem was, of course, to determine just how the hub/coaster brake worked, then I could determine why the problem existed.

The problem was the right side of the clutch was rubbing on the load bearing surface of the hub itself. Indeed, at some point, an imprint of the clutch's ridges was cut into the hub's load bearing surface. Thus, the loud ratchet type chattering that would go away if I moved the pedals back just a bit after pedaling.

Removing the imprint of the ridges from the hub's interior load bearing surface would be a challenge. I needed to determine the purpose of the ridges in the clutch. They appeared to be for one or two reasons........ To help the mating surfaces shed grit, grease and other impurities, and perhaps for cooling. The cooling was likely out, as friction would not occur on a positive mating surface.

Because the ridges on the hub's load bearing surface were so difficult to get to, I resolved to split the difference, decreasing the ridges on both the hub and the clutch. I used my Dremel with a slap wheel and slowly worked over the load bearing surface of the hub. Then I turned my attention to the clutch with a file and polishing wheel. I reassembled the hub inside the wheel several times, and spun it on the axle to determine if I had enough metal removed. After the third try, the noise was gone. I disassembled the hub one last time, cleaned and regreased and reassembled it, and installed the rear wheel on the bike. I spun it and braked to with the bike upside down, and everything seemed good. Tired, I went to sleep.

This morning, I woke up ready to test my work. Ilsa looked mournfully though the fence at me as I rolled the long brown Raleigh off the front porch. Click to enlargeThis was her bike to run alongside, and she knew I was going alone. After working over the brake, I needed to know for certain it was functional. I pedaled about five miles on the PUB, gingerly testing the brake as I proceeded. Finally I worked myself up to a full panic stop with a sideways skid. The brake worked fine. The chattering in my hub was gone.

I pedaled back home, leashed up my riding partner, and we spent the morning riding the neighborhood with no sound but chirping birds, humming tires, padding feet, panting tongues, jingling tags, and the envious barking of less fortunate dogs behind fences along the way.

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3 Comments:

OpenID trebor1415 said...

Hey Xavier,

I need some help and you seem to be the guy to ask.

I have my old Schwin Varsity 10 Speed (vintage '82 or so) that I just recovered from where it has been stored for 20 plus years.

The bike is in fair to poor shape. All the parts are there, but there is considerable dirt and some surface rust on the bright work. I think one of the rims is bent as well.

The local bike shop won't touch it as they say it is too much work.

I've never taken a bike apart. I want to tear it down and rebuild it bake to spec, replacing whatever needs replacing.

I need some serious guidance here as I've never attempted something like this before.

Any thoughts on good resources on the web or in print to learn more about what I need to do before I start?

Any other advice or tips would be appreciated as well,

Rob (Trebor)

1:26 AM  
Blogger Xavier said...

Rob,

If you look on my Bicycle blogroll, you will see links to several good sites. Sheldon Brown's site is one I highly recommend. Jim Langley's is another. Bicycle Tutor is a great video how to resource. There is at least one Schwinn forum online. I don't have that URL, but a Goggling should bring it up. In my amazon widget you will find several books, but most of this information is online in the form of web pages and videos.

ebay is one source of parts, and Schwinn parts are plentiful there.

Understand that "restoring" a Schwinn Varsity will not be a financially sound venture. When you finish, you will have two to three times as much invested in the bike as it would bring on the market. It is far better to simply make the bike rideable, or buying a mint example on ebay and having it shipped to you.

If you still want to ride your bike, replace only what you need to. Rebuild the rest. The cables can be replaced and the housings saved. All the bearing can be removed and regreased. The wheels can be removed and driven to the bike shop to be trued and have new rubber installed. Or buy new tires and tubes online, they are much cheaper that way. Sheldon brown's pages will teach you how to true a wheel.

Buy the specific tools you need. I can't emphasize this enough. A lot of folks try to get around buying bicycle tools, and end up buggering up the parts with improper tools.

Finally, assess your mechanical aptitude. Do you fix your own things? Can you take things apart and get them back together again? If not, see if there is a bike co-op in your town/city. Many larger cities have bike co-ops that teach people to work on bikes. It's a great place to learn.

5:48 AM  
OpenID trebor1415 said...

Thanks much.

I'm not trying to "restore" the bike for sale or do a museum quality job. I just want to ride *my* old bike again. I've had it since I was 12, and while I haven't ridden it in 20 years, it is MY bike and means something to me. That's why I want to fix this one up instead of buying a new one.

I understand it's not the most cost effective route, but that's not the point.

I'll read through the links and see what I can learn.

Thanks much.

1:03 PM  

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