My Ultegra 6510 9 speed right shifter broke. The screw holding shift lever to the back of the break lever popped out taking the threads with it. I don't know what the root cause of the problem but I was having issues shifting and I suspect that constant forcing while shifting on climbs likely caused the problem. I notice that the down shift lever is loose and wiggly and I suspect that the pin holding it place is becoming loose.
Now my issue is that the parts are obsolete. My bike is a Trek 5200 OCLV from circa 2002. Ultegra is now 11 speed, thus replacing it with a new Ultegra shifter is not possible without replacing the entire drive train and wheels, and I have a set Mavic Cosmic carbon wheels in addition to the stock wheels. Making an 11 speed upgrade not feasible.
The only new 9 speed shifter that I have seen is Shimano Sora 3500, but this seems to be major downgrade.
This leaves the option to upgrade to 10 speed. What will need to be changed? Obviously the rear dérailleur, cassette and chain. The chain rings will need to be changed regardless due to relative wear (new chain on partially worn rings). Is it possible to find 10 speed compatible chain-rings that will fit on an Ultegra 6510 crank? Or, is a whole new crank set required? Does the front dérailleur need to change?