Left shifter seizes up when warm?

bus_ter

My left front shifter (Ultegra 6700) has a recurring problem where it seizes up. As you push the lever to the right to change up it doesn't spring back to vertical. Even the small initial movement (before you start to pull cable) seizes and won't return back. I tried spraying loads of GT-40 in and removing the cables etc and nothing worked (it's 100% not a cable problem). The other morning I checked the bike and the lever was working ok?? My guess was the GT-40 had penetrated and loosened it up. However after a couple hours riding on a hot day it stiffened right up again and I couldn't use it. I just checked it this morning in the garage (much cooler day today) and it's fixed itself again?!? Seems to be when it warms up (and parts expand inside?) that it seizes up.

Any ideas?

declan1

I would imagine it's just dry inside and needs some nice grease. I presume you mean GT-85 or WD-40? They will only last a very short while and then evaporate again. In the cold garage it's probably quite moist and allows the lever to move properly.

bus_ter

Yes I meant GT-85. Even after about 30 seconds of spray with the stuff pouring out it doesn't ease up the lever. Not sure where/how to apply a thicker grease.

declan1

bus_ter wrote:

Yes I meant GT-85. Even after about 30 seconds of spray with the stuff pouring out it doesn't ease up the lever. Not sure where/how to apply a thicker grease.

Maybe something is stuck inside the mechanism?

Yossie

Buy a can of spray grease from any motor factor and spray a load in while shifting the lever through its motions to get the grease into all the working parts. .

The amount of GT85 you've sprayed in should have washed any small bits of crud out, otherwise take the shifter off the 'bars and have a good old nosey inside with a torch - when its in your hand you'll be able to see all around it better.