Old flight deck 9 speed Shifter jams up

[antnee]

Two weeks ago I had a lot ot difficulty changing gear on the rear cassette after cycling just over 30 miles Though I had gathered a lot of mud after going though some very suspect mud after clearing all the mud and adjusting the cable tension for the rear derailleur managed to get three gears on the cassette working I got home After stripping the cable out of the outer casing and Lubing up with some silicon refitted and got it working fine, Then today as it was the first time i'd been able to out to test it after a successful 29 miles and with a mile of home I had the same problem so before stripping the cable out from its outer casing thought I might try something that I omitted doing the first time round such as releasing the brake tension and giving the clicker mechanism a liberal dosing of chain lube found to my amazement it worked like a dream! I must add these shifters were not new when purchased, so probably have some wear on them. Just will have to see if this cures the problem if not I don't like to think about how much new ones will cost Anyone had this problem if so I would like to here your views Many thanks

 

[Drago]

Soak it in GT85 (other lightweight lubes/penetrates are available) and after a few days of soaking try again. Once working A1 give them a squirt of Wurth white grease.

 

[Ajax Bay]

As @Drago implies, "chain lube" is too thick for the innards of a STI. A good squirting every month / 1000km is good practice.
I have also found that the Flight Deck flat cable, which supports an obsolete function, sometimes gets in the way of things. The tape-like cable can be removed to reduce the risk of that.

 

[antnee]

Ah I hadn't given a thought to that. "The old flight deck flat strip cable" could and might well be perhaps the cause of the problem. Not sure about the chain lube being to thick? As the stuff I bought seems to be really thin, as if I lube up chain after cleaning I can see it drip off the chain so always place bike over plastic sheet and inevitably these alway some evidence of it on the plastic the next day. So how thin just is GT85? Also Should I strip Gear leaver completely to carry out this? Thank you both for your input.

 

[Ajax Bay]

If lube is thick enough to be used on a chain then, in my book it's too thick for inside an STI/Ergo (and I have these exact STIs on my audax bike (ST-4400) btw). I want my chain lube to stay on, no drip off, though (if indoors) I still protect the floor underneath and the wheel rim below (rim brakes). Once lubricated the chain is wiped. I'd expect no 'drip off' (and be concerned if there was). Look for threads on chain lubrication on here for an in depth discussion appraisal of chain lube choice.
GT-85 and similar is thin and will provide little lubrication bar some residual PTFE. What you're trying to achieve is to clean out the congealed lube in there from new and any gunk that's got in there (unlikely). GT-85/WD-40 does the job (and I'd expect some dripping from the STIs.
No need to 'strip the STI' (which is a one way street to oblivion btw - see below): just straw in from all directions including the axis of the cable (click to release all tension first) and a rag/kitchen towel undeneath.

 

[antnee]

Ah I see now just how many pieces there are so I won't tackle this if its not needed and as you say I have done some research on the GT85 and found as you say thats its comparable to good old WD40 will scoot off and get some In all fairness I've got to admit to never having come across GT85 before or the grease Wurth White. So will try and get some of that too.
I think it was you that advised me about checking the wire and nipple attachments re broken strands jamming the ratchet mech and have to say that that piece of advice certainly paid off as have been changing cables once a year On both bikes So Thanks for that good advise.