Author Topic: L/H STi failure - fixable? Advice please.  (Read 1293 times)

L/H STi failure - fixable? Advice please.
« on: 17 February, 2018, 03:24:02 pm »
So today my L/H shifter decided it had had enough of shifting, and left me stuck in the "big" (FCVO big) ring.  No clicks, so the ratchet that's supposed to release the cable tension, insn't. Fortunately despite my lamentable level of fitness I made it home without pain or walking, and even more fortunately I have the bits in the man cave to convert to full hydraulic discs, so have replacement shifters.

So, is the standard shifter (105 11sp) I have repairable at all? And if yes is it economic so to do?
We are making a New World (Paul Nash, 1918)

Re: L/H STi failure - fixable? Advice please.
« Reply #1 on: 17 February, 2018, 03:29:51 pm »
Check cable run first.

Then spray the fuck out of it with Gunk spray

Karla

  • car(e) free
    • Lost Byway - around the world by bike
Re: L/H STi failure - fixable? Advice please.
« Reply #2 on: 17 February, 2018, 03:39:06 pm »
The right hand shifters are the ones that usually break, so ebay is usually crowded with left hand shifters going cheap. 

Re: L/H STi failure - fixable? Advice please.
« Reply #3 on: 17 February, 2018, 03:54:10 pm »
Yes, it is repairable.
No, there isn't a manual or an online exploded view (Shimano's exploded view only covers partial disassembly) to help you. (and the amateur one that does exist, misses out a key and critical section - ETA - don't trust everything you read on the internet)
So, you will need to gain an understanding of how it works, by disassembly and investigative experimentation / assessment.
You will need to make some tools (spring retainers etc) to accomplish reassembly.
DNAHIKT.

I had this a while ago, when I was time-rich, but cash-poor, and needed to repair a Sora LH lever.
It is do-able, but I wouldn't jump at the opportunity to do so again.
Once you've established that there isn't any rogue inner cable jamming up the works (as per Flatus's advice)  I'd look at buying a replacement.

80, or so hours, and multiple, multiple re-builds during that time.

Re: L/H STi failure - fixable? Advice please.
« Reply #4 on: 17 February, 2018, 05:00:15 pm »
check cable runs, check the STI for bits of frayed cable, and then check the STI hasn't gummed up inside; remove the rubber hood and spray the parts you can see with GT85 or similar; they may free up and you have nothing to lose by trying this.

Yes you can disassemble and fix STIs but it isn't easy, it takes a long time and if there is a breakage inside it is usually a tiny spring that can't be bought and has to be modified/remade.  Gumming up is far more common than actual breakage.

BTW these shifters ought to have a 2-year warranty on them.  Back to the supplier with them if they are broken and  they are young enough!

cheers

Re: L/H STi failure - fixed by defualt
« Reply #5 on: 19 February, 2018, 11:23:52 am »
Cheers guys. Shifters are 4'ish years old, but have seen very little use as I was off the bike for 2 of them, only getting back to it last December.

Anyway, dismantled the lever from the bars, had to remove the bottom access plate to remove the gear cable (ie had to nundo a 1mm screw and take a coupole of bits of plastic off - not sure that is normal or not - because the cable end "button" wasn't visible), then, with cable removed the shifter seems ok again.  Cable not frayed, but some of the PTFE coating seemed to be raised/disturbed.

Anyway now on to fitting (and bleeding) the hydraulic replacement levers!
We are making a New World (Paul Nash, 1918)