stuckAt90Kgs

Hi all.

I'm dealing with an ST-6600G left shifter, controlling the front derailleur, that will only click once. Twisting the entire lever (i.e to go from small to large chainring) causes only one click or step. So, it appears there are no trim positions on this lever and hence, after installation (using an FD-5700 front derailleur), I am unable to get the chain onto the large chainring, no matter how much cable tension or H-screw adjustment I use.

When I say there are no trim positions, I mean that the shifter isn't able to access those positions and thus I'm pretty sure this shifter has had it. Just wanted to have some expert opinions.

Also, I take it there is little I can do to service these STIs apart from using liberal amounts of silicone spray lubricant to free up the internal mechanism? Which, by the way I have done, to the extent that I've nearly emptied an entire can of spray into this shifter to no avail.

Background: I bought the shifters as a pair off eBay for a fairly good price. Both shifters are in near-new condition and the right (rear) one works perfectly. Just the left one that's not behaving.

Thanks.

stuckAt90

ridelikeaturtle

Just to add a data point for you, based on my experience: I had an ST-6700 front shifter that suddenly "bit the dust", something in them got misaligned/broken and I just had to replace the whole thing, couldn't repair it.

It might be easiest to just get another and hope for the best.

Matt Gaunt

Just to be clear, I have not come across this on a left hand ST-6600. However, I have come across it quite a few times on right hand ST-6600 levers and have managed to rectify the issue on each occasion. Obviously, the two mechanisms are different but I think it is worth trying to save your lever.

You say you've sprayed a lot of lube into the lever, but I would try using a degreaser (safe for use on plastics) in the first place. The issue with the right hand levers I've seen is that the factory lube dries up, meaning the mechanism inside the lever cannot operate freely (or at all) so you want to try to break down the existing lube rather than just add to it. I have used GT85 to very good effect in this application (followed by a light synthetic chain lube once the GT85 has evaporated). You just want to operate the lever quite a few times whilst flushing its internals with your degreaser / GT85. Hopefully, you start seeing some improvement fairly quickly and you just keep going until you get full movement. You should see the old brown-ish grease getting flushed out - that's a good indication you're doing it right.

I would think this has to be worth a try before binning your lever.

andrewclaus

There's one stuck pawl in there and you have yet to reach it. As mentioned above, try a solvent, then a penetrating oil. If you know someone or have access to shop with an ultrasonic parts cleaner, sometimes that helps.

It's sometimes worthwhile to disconnect (but not remove) cables, and dismount the shifter from the bars, for better access for oiling.

I'm not sure about this specific shifter, but on some models it's possible to remove a cover (not the lever) for access to the pawls. A dental pick can then find the stuck piece and work it enough to get it back in service.

HillRider

Was the shifter set up properly? Did you click the release lever several times to get it to the most "relaxed" position before attaching the cable to the front derailleur?

Aubergine 

Geekage

You're aware that the trim positions are only available when lightly pressing the inner lever only, right? So trim is mostly to bring the derailleur cage in a little bit.

Yeah, that still doesn't help you with getting into the large ring.

Are you sure the shifter is moving the cable as far back as it can go? Sometimes if the cable is frayed near the head, you lose travel, so it might be a good idea to check your cable if you haven't already done so.

stuckAt90Kgs

Hi all. Thanks Geekage, I'm realising that now. Slight presses was missing from my mental concept. Cable was brand new, and swapping the shifter to a ST-5700 got everything working. But, I don't want to keep it this way (one side Ultegra and one side 105). The ST-6600 shifter will be brought back from the dead!!!

Anyway, thanks Matt Gaunt, andrewclaus and others who suggested that I try degreaser. I've taken the advice and have soaked the shifter in degreaser overnight. Rinsed out with water and hung up to dry on a clothes line in the hot Aussie sunshine for a day or so, and then hit it a second time with a solvent based degreaser. I've then reapplied lubricant and I can now "feel" the additional trim positions. Will let you know how it goes after reinstall.

Thanks HillRider. Will keep relaxed position in mind during reinstall. Am pretty sure I was fully relaxed when I did the install, but will drink extra beverages to ensure total relaxedness . Kidding aside, yes, I'm pretty sure there's no other way to install a new cable into the shifter.

Matt Gaunt

Good news.

Retro Grouch 

I'm not surprised.

The bugaboo of STI levers is dried up grease. People tend to use the rear shifter a lot so those internals get exercised regularly. Front shifters, sometimes not so much. My theory is that left STI levers suffer this problem more often than right shifters.

My bet is you'll be fine.