Shimano 105 STI failing to shift

Hello mechanics.

Please excuse my english.

I've done some research on the internet about the problem, but there seems to be different opinions on the solution, so I want to ask you about this.

The thing is, i've just bought a 1998 road bike with a pair of Shimano 105 8-speed shifting/braking levers. Both the right and left lever are having troubles shifting properly. It's like they wont "catch" the cable and pull it. I can move the lever, but theres no shifting action or any click sounds.

My research tells me it's old grease messing with the internal shifting mechanism.

Some say, that i should flush the entire lever with WD-40. People seems to agree this will help, but others say its a bad long term solution, and i should use citrus degrease, and then relube with chain oil instead.

I can tell this is a common issue with older shimano shifters.

What would you recommend?
Any good/bad experience?

thank you

I should add, that the shifters sometimes works as intended, but its only about 20% of the time, which was really annoying on the ride home from the seller.

Try to disassemble it and clean it thoroughly, then re-lube .

http://shimanostioverhaul.wordpress.com/shimano-600-right-rear-disassembly/

you can find some tutorials here and there. Usually a shitload of WD-40 will take care of it, but I'd rather get it apart, clean-relube it. For longevity.

I had that problem too with the right Shimano 105 8-speed Brifter (shifting/braking levers).

My solution? I unmounted the lever, just enough to have acess to all parts, and cleaned it with a small brush, WD40 and compressed air. Then, make it work up and down several times, so it releases the dirt/ old grease.

Lube it, and mount it again.