Trying to fix up a project bike... shifter trouble
I bought a rigid MTB w/o cables and housing (who knows where the hell they went!) about a year ago. I put the cables and housing on it but never rode the thing because I couldn't get the front derailleur to work. Anyway, a few days ago I decided it's time to work on the thing (and possibly replace front derailleur and chainrings, if necessary - I have some spares lying around). The trouble is: suddenly the rear shifter, that gave me no trouble before, is not working properly! I am embarassingly ignorant of techno-speak, so I'm going to talk about some things in rather layman terms... apology in advance!
So anyway, it's a 7-speed STX Shimano shifter, so if it's on 7, for example, and you want to shift to 1, you just go click-click-click-click-click-click 6 times - and there it is. The problem for me, however, is that it's only willing to click 5 times and not the sixth. After it clicks five times and you push the lever further, the derailleur moves and the chain shifts... but there is no click and as you let go of the lever, the chain falls back onto the smaller sprocket. I tried cleaning and lubing the thing - no success. I tried loosening the derailleur limit screws all the way - no effect on anything. Play with cable tension - nothing. In fact, I just unscrewed the derailleur bolt that holds the cable in place and let the cable hang completely loose - no improvement. It seems to be a shifter problem.
Now, another thing is that is wrong is the little display thingie: there are numbers displayed on the shifter and a little red indicator that is supposed to move when you shift gears so as to highlight the gear you're currently at. When you take the shifter apart (which I did in order to pull the cable through, and several times after that to clean/lube it in an attempt to fix things), I can see what moves the red thingie (simple mechanical action) but I am not able to reassemble the shifter in such a way that it moves the display... it's just stuck at 7. I wonder if that's actually interfering in any way with the shifter action.
I'd probably just say the hell with all this and replaced the shifter, but unfortunately it's a shifter-brake combo, so I'd have to pay extra to replace a perfectly good brake lever... and I'm trying to keep the price to a minimum cause this is supposed to be a beater! Any suggestions about things I can try or is this just hopeless?..