Paging Old Potato 7800 STI issue...AGAIN!

[mgm777]

Last winter, my right STI (vintage 2005 7800 DA) inner lever wouldn't move the rear derailleur. Old Spuds, who always professionally and meticulously overhauled my bike(s) several times before he retired, recommended I employ his tried and true "STI Repair Kit". So, not wanting to question authority, I did as instructed and flushed the STI with WD40 and afterwards followed up with a light lube.

For the remainder of last winter, the spring, summer, and fall seasons the STI worked flawlessly. Shifting up and down the cassette was effortless. The "STI Repair Kit" worked famously well. Fast forward to today.... This morning I am riding, it is about 35 deg outside, and the inner lever starts malfunctioning again. I can move the inner lever, but nothing happens. The larger, outside lever will move the rear derailleur, but inner lever won't and the chain eventually gets fixed on the largest cog of the cassette. I am wondering if the cold temp outside has something to with the failure mode? Should I attempt another round of the "STI Repair Kit" or just chalk it up to stuff wears out and consider a replacement?

[kgreene10]

Check the cable. When it frays near the head, it can become possible to pull it but not release tension. Something similar just happened with my DA 9001.

[jc031699]

I have been doing a little research on this lately.

Everything that you need should be here.

http://forums.thepaceline.net/showthread.php?t=128412&highlight=Shifter+wd40

Cold weather can definitely make the old grease more sticky. Just happened to my Ultegra 9sp shifters. Voluminous PB Blaster and removing the cable did the trick for me.

[TBDSeattle]

Blog on overhauling STI shifters... (http://shimanostioverhaul.wordpress.com/)

Checking for frayed cables, and rust in housing is always my first step. I lube cable ends, then push through with compressed air.

Second step for me is the WD-40 flush.

Then I wait for WD-40 to evaporate (overnight), then throw in a lube. I like spray in lithium grease.

[Bradford]

I think the cold has a lot to do with it. Two winters ago, my right shifter wasn't working consistently. When it warmed up, the problem went away. It was fine over the summer, then started up again in the winter. I thought it was the gloves at first, but the WD40 bath is what fixed it.

Last weekend, same thing, but now on the left. Yesterday I flushed with WD40 and blew it out with compressed air, today I lubed it up, and it is working good as new.

Seems to me to be about 40 degrees and below that causes the problem. Now that they are both flushed out and freshly lubed, I'm assuming that I won't have any problems going forward.

[jc031699]

Have thought about this some, and I think pulling the cable all the way out vibrated the stuck pawl free after the PB Blaster had been working for a while.

[bargainguy]

Brifters: I flush with CRC PowerLube instead of WD-40 and a separate lubricant. It has PTFE which serves nicely as a lube. Never had a freezing problem.

[pbarry]

^^. This. I've used Tri-Flow on STIs, and did not have any further problems.

[EPOJoe]

One of my brifters developed this kind of problem due to a little front/back play in the smaller lever. Found out the small lever works fine if I apply a little forward pressure while I'm pushing it to the side.

[oldpotatoe]

Last winter, my right STI (vintage 2005 7800 DA) inner lever wouldn't move the rear derailleur. Old Spuds, who always professionally and meticulously overhauled my bike(s) several times before he retired, recommended I employ his tried and true "STI Repair Kit". So, not wanting to question authority, I did as instructed and flushed the STI with WD40 and afterwards followed up with a light lube.

For the remainder of last winter, the spring, summer, and fall seasons the STI worked flawlessly. Shifting up and down the cassette was effortless. The "STI Repair Kit" worked famously well. Fast forward to today.... This morning I am riding, it is about 35 deg outside, and the inner lever starts malfunctioning again. I can move the inner lever, but nothing happens. The larger, outside lever will move the rear derailleur, but inner lever won't and the chain eventually gets fixed on the largest cog of the cassette. I am wondering if the cold temp outside has something to with the failure mode? Should I attempt another round of the "STI Repair Kit" or just chalk it up to stuff wears out and consider a replacement?

Will the small lever work, shift the RDer, if you hold the big lever outboard??

If it does, yes another squirt/flush. If it doesn't...there are only 2 types of STI, those that have failed and those that will. May be time for new ones.

BUT also take the housing out and check the cable end..these levers eat cables.

[Cicli]

Will the small lever work, shift the RDer, if you hold the big lever outboard??

If it does, yes another squirt/flush. If it doesn't...there are only 2 types of STI, those that have failed and those that will. May be time for new ones.

BUT also take the housing out and check the cable end..these levers eat cables.

Correct me if I am wrong but I thought the cable eating issue started when the shift cables went under the tape. 78,66,56 series shifters didn't really have as much of an issue.

[oldpotatoe]

Correct me if I am wrong but I thought the cable eating issue started when the shift cables went under the tape. 78,66,56 series shifters didn't really have as much of an issue.

Not in my experience. 7800/6600 had this issue in spades. 7900/6700, not so much..9000 again...

Nice thing about 7800/6600, easy to check. 7900/6700, not as easy.

[Cicli]

Not in my experience. 7800/6600 had this issue in spades. 7900/6700, not so much..9000 again...

Nice thing about 7800/6600, easy to check. 7900/6700, not as easy.

Right on. I have had a bunch of experience with both and have not seen any issue with eating cables. That said, I stay after maintenance pretty hard too. Cables are cheap and can be changed in minutes.
If I was dealing with customers that don't take care of stuff or wait until it fails I may be singing a different tune.

Thanks.

[kgreene10]

My 9001 is eating even more cables than my 7800, which are it's fill.

[fmradio516]

I always thought WD40 was bad for anything on a bike but I guess here is a good use. Glad I read this