Flappy Lever

[spence]

XT M770 left-hand shifter, the 2-way release lever (upper one) doesn’t always work ie release cable to drop down the front rings. I guess it’s not engaged with whatever it’s supposed to in the mechanism as it flaps about. If I push the thumb lever a few times it will eventually engage the 2-way release lever but then again be flappy after using it.


It’s not a sticking cable as that is moving freely. I’ve put extra tension through it by hand and the lever will still not always engage after an upshift.


Anyone else experienced this and what’s the fix? Everything is clean and well lubricated. Looking for clues before I strip it down.



Thanks.

 

[fossyant]

Don't strip it, the best you can do is WD40 into the mechanism. Next replace cables (I know you said clean, but has any frayed in the shifter ?), then I am afraid it maybe a new one.

You are a braver man than me if stripping a STI

 

[spence]

Thanks. I guess it may be a frayed at the shifter end.

Do not use WD40 as a lube as it will flush out any on the original grease left in the shifter and then dry out. Unless that's your intention. If it's to lube use a spray, TF2 or FinishLine for example.

I've only removed Shimano innards as a whole before, when a casing has been damaged. Have completely striped, cleaned and rebuilt SRAM Rockets in the past. Not that difficult.

 

[2Loose]

My front mech (Deore) wouldn't change since the snow thawed, same symptoms. Flappy shift levers and no click until I pushed it all the way and pulled the cable tight again. Not all of the time, but most.

I put it down to salt spray & grit in the mech because the cable was sliding well and getting loose when the mech 'should' have sprung down to the smaller rings, but the mech wasn't moving without a little nudge, then it moved a bit jerkily.

I took the mech off, cleaned it in hot soapy water and oiled it with lots of physical manipulation to work it in. It had improved but was still not smooth.
Copious WD40 has flushed the crap out properly (I have re-lubed the pivots since) and all is well.

Just to be sure, nudge the mech downwards when the lever is loose and see if it takes up some of the cable slack smoothly or not.

I pick up full mudguards this weekend as a preventative measure and hopefully help keep the mech clean.

 

[spence]

Thanks for the thoughts. I've seen/experienced your scenario - then mud and sandy grit around here are terrible for doing that - but it's not the case in this instance. The mech moves freely and tensioning the cable buy hand has no effect.

Studying it more last night, the lever releases cable some times on a forward push (thumb) but never on a back pull (index finger) indicating, to me there's something up with the mechanics inside. Guess it's screwdriver time.

Oh and no to the mudguards.........