Partially disassembling Sticky Shimano STI shifter for service There are a few questions floating around regarding sticky STI shifters and the standard procedure seems to be to flush with a load of WD-40 and relube with aerosol grease or similar.

My set is Ultegra 6500 series.

Having tried this with with unsatisfactory results I think I need to take more drastic action. It is clear there is still significant grime and gummed-up grease in the mechanism (excerbated no doubt by long-term lack of name plate). I figured the best method would be to remove the shifter from the bike and give it a good submersion in degreaser.

My idea was to leave the body on the bars and just remove the lever, which incorporates the mechanism by removing the pivot pin and brake/gear cables. The tech docs show this process but I'm slightly scared of tiny pieces flying everywhere and being unable to reassemble. It also requires a "return spring installation tool" which I do not possess.

Has anyone had experience with this? How tricky is it for a reasonably technically inclined person? Would I be better off just removing the bar tape and taking off the whole unit?
So, after studying the tech doc I took the plunge. It is actually not difficult and the only tools you need are some hex keys. I managed to successfully remove the lever assembly from the shifter for cleaning. Just don't try to disassemble any further than the doc instructs.

The bad news was that even after a thorough soaking in degreaser (which turned black from the grime) and relube, shifting performance has hardly improved, suggesting some mechanical issue. I think some new shifters are in order.

Reassembly for almost as easy, the only slightly tricky bit was getting the return spring in the right place without the official tool. A bit of poking with a pointy implement solved it though.

Conclusion: definitely a viable and effective way to clean shifters - if grease and grime buildup is the cause of stickiness.