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A search gave me the 2011 thread about slipping shift levers, but I'm not convinced what my problem is quite the same. Manual on my '88 Bridgestone 400 says it has an AL11GS L434 lever SIS downtube mount type. I can read the SIS, and it's on the downtube, and the original owner paid no attention to this bike so I'm sure that's what it still has. I've had and ridden the bike for about a year. I had to tighten the tensioning bolt once a couple of weeks ago, which was no surprise. It loosened yesterday to where it settled on the smallest chainring, and I screwed the bolt tight again. My commute is not much more than 3 miles, and that bolt came loose both going in and coming home. I'm now riding with a stubby screwdriver in my pocket.

What could have changed? What part of this wears, and has to be replaced? I don't like the sound of Loctite as a solution. Holding the lever in position to be able to ride in the middle gears is not a good option. Help! Thanks.

mh

Marsha Hanchrow
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    If you feel competent to do it, the first thing would be to take the shifter apart (be careful not to lose any small pieces!) and clean the pieces thoroughly. Don't use a petroleum product, but simply wash in a detergent solution (and then dry). If there is a blue plastic-like substance on the end of the screw, do not attempt to remove it. If this doesn't do it you can apply Loctite purple to the threaded end of the screw (not to any other components). The purple variety (#222 -- which strangely comes in a red tube) is adjustable and likely is what was on there to begin with. – Daniel R Hicks Sep 01 '16 at 11:55
  • Welcome to [bicycles.se] @Marsha. As with all new members, we recommend you take the [tour] to make best use of the site. While the question Daniel has nominated may not look like a duplicate, it's the answers that count. The top answer by Gary seems to be exactly what you need. If that doesn't solve the problem, then edit your question to include the extra info about what happened when you tried it – andy256 Sep 01 '16 at 12:03
  • I took the thing apart today, and a broken piece fell out. I'm surprised and impressed that it's worked for the year I've owned the bike, running on crumbled pot metal. I'm now hunting for a replacement (of the same kind). New old stock out there anywhere? – Marsha Hanchrow Sep 03 '16 at 22:14
  • Theres a ton of friction shifters on the market -- unless you have some need to having a matching set, any front friction shifter will do. – Batman Sep 05 '16 at 21:11

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Friction shifters eventually need to be taken apart, cleaned, and re-lubricated to solve the problems you mention. Be very careful to keep the parts in order. You'll find advice on the above mentioned other thread not to lubricate them, which is wrong. All the surfaces should get a thin film of oil or grease, ideally something that doesn't harm plastic presuming your shifter has plastic washers, as most do. Using a mild or medium strength Loctite is optional but is a good further safeguard against slippage, and won't keep you from loosening them on purpose. Some people use beeswax as a substitute.

The plastic washers inside can degrade, which wouldn't be surprising on a 30 year old bike. If so you probably just need a new shifter unless you want to get crafty and find or make new ones.

Nathan Knutson
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My solution so far has been to order a set to replace the broken one. I could not get a set for braze-on mounts at a reasonable price in a reasonable amount of time, but was (I hope accurately) told by the seller that I could take apart his clamp-on pair and mount to the base that's still on the downtube boss. We'll see in about a week.

Marsha Hanchrow
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