1993 Trek 2300 with Shimano 600 shifters on the brake levers

[Oldgiant]

Gents - new to the forum but glad I found it. My right lever to down shift to lower gears (smaller back chainrings) works occasionally or not at all, while the bigger lever (brake lever) for up shifting to a higher gear (bigger chainring) works fine. Any idea what is going on?

 

[Oldgiant]

Just a bit more info, the shifters are the Ultegra ST-6400 8 speed version.

 

[Wyvernrh]

If you are lucky, pumping the lever full of WD40 or similar and working the lever will clean out the accumulated crap and it will all work again. If it still doesn't work then it will be rebuild time and often replacement is easier and often cheaper.

 

[Oldgiant]

If you are lucky, pumping the lever full of WD40 or similar and working the lever will clean out the accumulated crap and it will all work again. If it still doesn't work then it will be rebuild time and often replacement is easier and often cheaper.

Man you're a genius. I removed the back wheel, so the lever would open completely, then moved the shifter lever some to open up the space behind the cover and filled it with WD40 a couple times and let it sit for a few minutes. I then did the same thing and shot it with pressurized carb cleaner a few times. After that dried, I reinjected it with WD40. Works like new. Thanks again.