Ok I want to wow all your mechanics that may or may not respond by trying to have the most thorough first post anyone can ask for, so here we go....... (I am an auto mechanic so I understand the "my car is making a noise, what's wrong with it?" nonsense)
I recently picked up a used Allez, 1999, with the 105 Flightdeck shifters on it (ST-5510). When I first looked at the bike it shifted fine on both front and rear through all the gears. After getting it home and riding it on the trainer the rear one almost immediately stopped shifting. It will sometimes go through all the gears, but mainly it down shifts without problems but will only upshift a few gears and then the shifter feels as if it isn't "gripping" the cable. There is no tension on the shifter it just rotates easily.
A few things seem to get the shifter through it's non-shifting funk:
- Pulling on the cable where it runs along the downtube
- Shifting down one and then immediately back up (small lever then big)
- Some times pulling the brake slightly will engage it
- Rapid jiggling of the handle
- Cussing.....lots of cussing
And then sometimes it shifts fine several times up and down without so much as a skip or losing tension on the shifter.
After searching I wasn't able to find anyone with the same issue (IAFAIK), but have read that this is a common occurrence with Shimano shifters, or at least that is what I gather. I am guessing they need a good cleaning and have found these threads with info on doing so (the MTB forum one being what sounds like more thorough):
Things that will be done in the near future once a work bonus comes in and I can get outside to clean:
- Replacing all the cabling/housings since it looks beat up
- Replacing the plastic guide thingy on the underside that the shifter cables run over the BB on
- Clean like crazy....everything
I want to know if a good soaking and new cables and housings will be what sounds like will fix my "limp" shifter? Also I read the break down from Shimano and the internals are all serviceable, is that true? I read over some different shifter tear downs on here and they all look similar but aren't a 105, so would Kimmo's tear down thread (or several other) be what will work? And what is an appropriate length for the RD cable housing since that seems to be a problematic spot for the RD and shifter.
And as for the MTB forum post, will completely soaking the shifters be safe for the internals? I understand the hoods should not be soaked so those will be taken off. Thanks for any help ahead of time!