Shimano rear shifter loose - won't shift at all

[cvondrick]

Hello,<br />
I recently acquired an old mountain bike. I am no bike expert so I know very little terminology, but I am trying to fix it up. I spent the day working on it and now it is ridable, however I realized that the rear shifter seems broken. The front gear shifter works great, but when I try to change 7-speed gear, nothing happens.
In particular, when I try to change the rear gear, I do not feel any "tug" on the wire that goes to the rear derailleur. I am led to believe that the problem is somewhere with the wire. I have adjusted the wire to be tight, but I still do not feel any tug from the shifter.
Is there anyway to diagnose the problem further, or even better, fix such a thing?
If it matters, the shifter seems to be a Shimano 200 GS. It appears they do not sell these anymore, so buying new ones seems out of the question.
Thanks for your reply!

[cvondrick]

I should have mention as well -- when I pull the lever to change gears, there is no resistance. The lever just slides. In comparison to the front shifter, there is some friction that forces me to push a little bit harder.

[cyclerUK]

Initially it sounds like the cable is broken.<br />
If you can pull the inner wire from some where on the frame then it may pull out. completely.<br />
See Park website (Shimano STI) may help:<br />
http://www.parktool.com/repair/readhowto.asp?id=117

[julian]

Hi,
I have the same problem - the cable it not broken. Did you manage to fix it?
Thxs

[Bill]

Move the derailler and see if it is movable. If it is then like cycler says it is probably a frozen/rusted wire inside of the cable housing. If this is the problem then you will need a new cable/housing.

[julian]

Thanks for the reply Bill. The derailleur (Nexave 7) moves both vertically and horizontally. Most of the wire cable has no housing. it is loose along its length but I cannot pull it free at any point. If it had become stuck, does that mean that it has partially (but not completely, and hence cannot be pulled free)) torn inside the gear shifter housing? In any case, will I necessarily have to take said housing apart to fix this?
Regards,
Julian

[Joe_W]

OK, maybe the cable is frayed (or just gunked up), it sounds like that. Either try to lube it or replace. Cable plus housing should be not too expensive. Go to the local bike shop and get it there. If you take your bike they should be able to cut the housing to the correct length (it is usually sold from a huge roll). They could also tell you whether it is probable that the cable is the culprit (though this is likely from your description).

[julian]

Thanks Joe,

actually, I was not referring to the plastic cable housing, but actually the metal casing of the gear shifter. I'm trying to work out why the wire cable itself is slack without being broken (I can't pull it out) before I start repairs to see if I need to take the gear shifter casing apart.

[Bill]

Not sure if this will help, there is no diagram but good information here. http://www.cyclingforums.com/mountain-bikes/171079-sti-shimano-200gs.html .

[Joe_W]

Grrr... I was going to write that diagrams were available at http://www.paul-lange.de, but they only have them back till 2005... Your shifters are about 20 years old, so you have got to find them somewhere else. Or maybe write shimano or paul-lange.de to get the explosive views.

[BStephens]

[quote='cvondrick' pid='2449' dateline='1253409773']
Hello,<br />
I recently acquired an old mountain bike. I am no bike expert so I know very little terminology, but I am trying to fix it up. I spent the day working on it and now it is ridable, however I realized that the rear shifter seems broken. The front gear shifter works great, but when I try to change 7-speed gear, nothing happens.
In particular, when I try to change the rear gear, I do not feel any "tug" on the wire that goes to the rear derailleur. I am led to believe that the problem is somewhere with the wire. I have adjusted the wire to be tight, but I still do not feel any tug from the shifter.
Is there anyway to diagnose the problem further, or even better, fix such a thing?
If it matters, the shifter seems to be a Shimano 200 GS. It appears they do not sell these anymore, so buying new ones seems out of the question.
Thanks for your reply!


Reply Note ============================
=====================================================
These Shimano Levers need regular lubrication. There are small spring loaded levers inside that rock back and forth on spindles. When the
spindles or levers get rust on them they become stuck, the small springs
cannot push the levers back to engage with the central gear that pulls the cable. This gives a feeling that the shifter is doing nothing.
The plastic cover on the bottom of the shifter can be removed.
It has a phillips screw holding it. It can be completely removed which isn't easy due to the cable guide tab with the hole in it. Or the screw
can be removed and the cover pulled back to expose the works inside.
The stuck levers are then oiled and wiggled back and forth with a small screwdriver until they move freely.
This attatched photo is the shifter for the Front/chainrings but the rear
shifter has a similar mechanism.