danieljnolan

Hello

I have a 105 front shifter here which won't drop from the big to small ring. Happened all of a sudden on the road.

Cable tension etc is OK. When I push the lever rightwards, the smaller metal lever that usually clicks up and right simply swings out without any resistance and then stays stuck out towards the bike stem. I can push it back easily - no resistance on it.

I've (technical term) spaffed a load of W5 into the lever having taken off the cover and removed bottom plate.

What next? Site won't let me attach a pic unfortunately but hope above is clear enough.

Thanks in advance

Andrew R Stewart 

How about which model number and which double/triple? Some had known issues with internal breakages, all are like any STI lever in that in time the lube dries out and becomes gummy.

Sure sounds like something might have broken inside to have come on so suddenly. Are you able to shift off the big ring with any lever fiddling? Or is the shifter still stuck in the big ring? Andy

Troul 

If the brake action is engaged, it'll not let the shifter execute its sweep.

danieljnolan

St-5800, double chainring. Sorry was unsure of model but have located the stamp

danieljnolan

- no amount of fiddling with the shifter itself or the small metal lever it usually clicks into place shifts the gear. It remains in big gear
- brakes loosened off and everything moves freely with the shifter, just without any weight/resistance behind the small metal lever when trying to shift

Troul 

Using your finger, try pulling the metal lever as you move the plastic lever at the same time.

danieljnolan

I have just tried this: they both reach the end of their arc and can be returned to where they started, but nothing happens at all.
I assume it's possible that whatever action the metal lever has, the piece it connects to inside has broken?

Crankycrank

+1. Before trying anything else, do a flush with some solvent (WD-40 works well for this). Check out a few of these YouTube vids for how-to and most of these are not for your exact 105 STI's but same basic method. (1) how to flush shimano sti shifters - YouTube and this is one of my favorites. Note that leaving any WD-40 residue on the rubber hoods will turn it to goo over time so clean it off really well. My guess but I think the mineral oil in it is the culprit so don't do the final lube with mineral oil.

danieljnolan

Opened it up some more to flush out and found what appear to be the remains of a spring attached to the end of the small metal lever. Assume a spring normally attaches it to another part in the mechanism and that this has snapped? New shifter time I assume. Thanks for help

Iride01 

Have you released the cable from the pinch bolt on the FD and then pulled a few inches out of the STI to make sure it isn't frayed?

If you put your pic's on the Gallery here at BF, we can find them. But today you should be able to get your additional five posts answering various questions or making useful comment in other threads. Still might need another day though after getting that magical total of ten posts.

choddo

I had exactly this happen to a 2 month old Ultegra 6700 shifter. Completely lost the downshift action. Suspect the same fault as yours. Warranty job in that case, luckily but I actually bought a replacement as I didn’t want to wait. Shimano sent just the internal mechanism, no levers, and I still have it in a drawer over 10 years later!

Koyote

You can stop wasting WD-40, because your shifter is broken. Same thing happened to one of mine.

The solution is a new STI unit.

wheelreason

Yup, broke.