JSJensen

Folks Thanks in Advance from an old school cyclist who now has a little problem with components I have been very happy with. I have a 200x generation Trek Carbon Fiber bike that I bought used over 10 years ago and still ride it. I've developed a problem with the shifters - originally just the rear derailleur but now both. From the brake levers, the large lever (shifting to a larger cog) works fine, but the smaller lever doesn't seem to want to catch inside the shifter and just swings in and doesn't actuate the cable. With some jiggling, tapping, smacking, I can eventually get it to catch, but it is *completely* unreliable now.

Some background - I have addressed this in the past (2-3 years ago) by flooding the shift lever assembly with WD-40 for cleaning, and then silicone lube. Helped, but not completely....

In 10 years, I have *never* changed out cables. In searching for a previous post on this, I found a related one where a fraying cable was causing problems, and that could be my issue as well. But I haven't had a chance to look for that yet, and thought it better to get my question posted tonight.

Appreciate any help or reference - it's just too flakey at this point to use, and I am anxious to get riding again this spring. I'm a past triathlete but I never liked running as much as riding.

Thanks

Andrew R Stewart 

Since a frayed cable is so easily found and cured I'll wait for you to check that out first before going further. Andy

bwilli88 

10 years is a long time for shift cables, Change them and get back to us.

tFUnK

Not much more to offer beyond bathing it liberally with degreaser or WD 40 and regreasing.

dsbrantjr

If you do have a frayed cable you would do well to replace it before the head breaks off inside the shifter, where it is very difficult to get out.

dedhed

Change both the cable and housing.

Andrew R Stewart 

Before the Op spends money I suggested he finds out the real condition of the cables. Anything else is throwing money at something with no target. Andy

cpach

Holy goodness, change your friggin cables and housing already. This is normal annual service for a road bike. Shimano road shifters in particular love to fray them inside the shifter. CHANGE YOUR CABLES (and housing).

JSJensen

To all - Hmm, I'm getting the idea that new cables might be a good idea. Lol.
Thanks - will check and get back to you, with pics if I can.

JSJensen

OK - so an inspection of the shifter cable shows it in surprisingly good condition. No fraying and no gunk. The small shifter problem persists even without the cable tensioned in the shifter. I will attach a photo momentarily.

I did notice another aspect of the behavior: I realized I can make the small shifter actuate properly if I apply *forward* pressure on the small shift lever as I move it to the left. (This applies to the right handlebar, aka, rear derailleur). So once the lever clears the larger shift lever (brake), if I push forward as I continue moving it to the left, it will operate properly. If I just push laterally to the left, the lever swings freely but doesn't catch the shifter inside.

Thanks - I come with no ego to this forum, just grateful for any tips or advice you can offer. I'll add a pic next.

Stu

JSJensen

Andrew - cable in surprisingly good condition after removal this evening. Apparently I'm not allowed to post a pic until I have 10 posts...? Appreciate any further thoughts. I added some more insight to the symptoms in another post just a short while ago.

tFUnK

Ditto, same with mine (albeit 6600). Maybe it's time for a solvent or ultrasonic soak 🤷‍♂️

Crankycrank

Well, just to give you some hope that's what my 6600 shifters usually do when they need a flush and lube. No guarantees but hope that's all you need.

Andrew R Stewart 

It sounds to me that the pushing of the release lever forward as it passes by the primary blade is doing much of what I described, keeping the primary lever stationary. If so then I suspect your lever won't return to proper function with a thorough solvent flushing and relube. But these levers have a few age/failure modes that overlap in how they present. If these were mine I would do the flush and lube because I can then see what developed. Andy

JSJensen

Thanks everyone. A very heavy flush and lube seems to have done the trick. They are operating well and reliably shifting... I will however be ordering new cables and shrouds. I'm clearly on borrowed time in that regard.