Shifter broken?

[nils]

Hey

I have a Shimano 105 shifter like this one for my rear derailleur:

It is now broken like this: after loosening it completely (lowest gear), I can only push it once (it clicks about 3-4 times) which gives me about one step/gear up. After that, it doesn't give me any more gear shifts (it's very loose). So basically I only have 2 gears right now.

My idea is that it normally "rewinds" itself, so that you can get all gear changes done (usually push it 3-4 times to get from lowest to highest gear), which is now broken. Push it once, let go, push it again, let go etc.

I hope that I have been able to explain my problem. My question is if this can be fixed, or if I have to buy a new shifter?

[xerxes]

I'd have a go at fixing it before buying a new lever, you don't really having anything to lose, other than the time you spend.

I've never actually had a close look at dual control levers, but I imagine the mechanism is not that dissimilar to to MTB shifters, basically a pulley and a ratchet. These generally work pretty reliably, but it might be worth opening up and flushing it out with some degreaser, to make sure the mechanism isn't gummed up, then apply some fresh spray grease, reassemble and try it out again. Also clean and lubricate the cable so that it runs as smoothly as possible through the outer, or replace it completely it if it looks worn or corroded.

Alex has a video for overhauling rapid fire shifters here: http://bicycletutor.com/rapid-fire-shifters/. I know they're not the same, but the general procedure should work.

You can find Shimano's technical documents here: http://techdocs.shimano.com/techdocs/blevel.jsp;jsessionid=dmpMMN2CtfZh1hpd9dfTGNL2CcvHxTydQd5Vnjhm39zhPTphLLQQ!21057​42464?ASSORTMENT%3C%3East_id=1408474395181679&FOLDER%3C%3Efolder_id=2534374302051113&bmUID=iDD3AVG