Bicycle Mechanics - Ultegra 9-sp rear shifter "slipping"

Hi all, occasionally i go to shift into an easier rear gear, and push my right shifter in, and get no resistance and nothing happens, as if it has completely missed whatever it is supposed to catch on in the shift mechanism. This happens maybe 10-20% of the time, but can be very frustrating when you're about to hit a hill and don't quite shift in time. It always works the second time around.

I've never taken one of these things apart. 1) Does this mean the indexing / mechanism in my shifter is shot? 2) How do I fix this? 3) Can I do it without a new shifter? Any links to instructions or diagrams of what I need to do would be helpful. Cheers.
SFH

Do not take it apart unless you plan on never using it again.

It sounds like your heading for a new shifter, honestly. You can try flushing out the mechanism and then pouring some lubricant down into the works (click through the gears a bit as you do it). Sometimes this can work loose some grunge and get a bit more life out of the shifter.

You have discovered the sad truth about Shimano brifters: once they go they are gone. The good thing is that a replacement may be less $ than the parts to repair a Campy! If flushing with something like gasp, wd-40 does not work, time to replace.

+1. Shimano STIs are really unfixable except to flush them thoroughly with mineral spirits, kerosene, WD-40 or similar solvents, relube and hope for the best.

How old and how many miles are on your shifters? I've always had very good service life from STIs but, when they go, they are gone.

That's what I feared . . . The shifters are from 2002, about 3000+ miles. Is this what I should expect from them?

Also, how exactly do I flush it out? Do I need to take it off the bike, or just spray as much wd-40 into it as I can? Is wd-40 best? any other recommendations?

That's what I feared . . . The shifters are from 2002, about 3000+ miles. Is this what I should expect from them?

Also, how exactly do I flush it out? Do I need to take it off the bike, or just spray as much wd-40 into it as I can? Is wd-40 best? any other recommendations?
That's a very low service life. I've seen 30,000 miles from several sets of STI's.

Removing the lever from the bike and immersing it in solvent with plenty of agitation is the best method. Basically, WD-40 is just very expensive kerosene in a spray can so it's easy to apply.

That seems like low mileage unless you are in the habit of dumping sand into the gears. Do you ride it in bad conditions or has the bike been crashed?

No, the bike has been well cared for, maintained regularly, kept indoors, etc. Worst its seen is a little rain here and there. Hopefully it is just a lodged piece of something in there . . . I was also surprised that it started to fail so early . . . I'll try removing the shifter and giving it a good clean and relube. Thanks for the input.

One more thing, check the shift cable. If it's frayed, has a broken strand or is rusty and binding, that could be causing your problems.

New cable. I had my whole gruppo put on another frame and shifter cables replaced. The problem was occurring before, and I thought maybe it would go away when things were re-installed by my LBS on my new frame. I thought it was gone, but happened again on my first ride out, unfortunately.

When this happened to my 9-speed Dura-Ace I sprayed lots of WD 40 into the shifters (using the straw). That was 7 years ago and they've worked perfectly since then. Apparently the factory grease had become hard.
3000 miles is nothing for Ultegra shifters.

Al

I've found STI shifters on mountain bikes to be alot easier to flush and clean due to the small panels you can remove. When it comes to the road levers, wd-40 and compressed air work the best. Lighty lube the inside and give your cables a tug. Also checked for a kinked or jammed cable, another thing that can make STI's seem stubborn.