Author Topic: New front shifter jammed/not pulling?  (Read 1219 times)

New front shifter jammed/not pulling?
« on: 15 June, 2017, 07:56:17 am »
This was unexpected... Installing the new front shifters (105 5703), and main shifter lever (A) (on front LHS "triple" shifter) for moving the chain from small to large front chain ring has no clicks - seems to be 'jammed'.  One can push it to the right, and it moves to a stop with no clicks and without pulling cable.  Return (B) lever (plastic) does seem to have 'notches' rather than clicks, perhaps OK.  Any ideas/seen this before?  Anything I can do myself? 
Cycle and recycle.   SS Wilson

Re: New front shifter jammed/not pulling?
« Reply #1 on: 15 June, 2017, 08:53:11 am »
Guessing here - but I had something not dissimilar on a Campag lever once.
Turned out I'd mis-threaded the cable through the shifter.  (it had gone between the ratchet mechanism and the body rather through the mechanism) 
Don't know if that's possible on twin-paddle shifters like the 105

Re: New front shifter jammed/not pulling?
« Reply #2 on: 15 June, 2017, 08:59:16 am »
Thanks.  The cable was pre-threaded, so all I had to do was fit casing and attach etc.  The shimano manual pdf shows that one can disassemble the lever to some extent (with an extra tool), just don't know what the issue is... perhaps I should try and return them...  :-\
Cycle and recycle.   SS Wilson

Phil W

Re: New front shifter jammed/not pulling?
« Reply #3 on: 15 June, 2017, 09:06:47 am »
If you take the lever off the bars you find a small grub (middle of photo) that can come loose and cause the symptom you describe. I believe the grub holds all the cogs of the shifting mechanism together etc. See if it's loose and if so tighten it up with 2mm allen key and see if that resolves it.




Re: New front shifter jammed/not pulling?
« Reply #4 on: 15 June, 2017, 10:08:29 am »
Thanks, will take a look at that.  Not sure how it may have worked loose, but would be good if it's something simple.  It seems unlikley the shifter is actually 'broken'...
Cycle and recycle.   SS Wilson

Torslanda

  • Professional Gobshite
  • Just a tart for retro kit . . .
    • John's Bikes
Re: New front shifter jammed/not pulling?
« Reply #5 on: 15 June, 2017, 11:13:40 am »
Take the cable out and work the inner lever so it is in the lowest position. Please note that the inner lever will sometimes not engage the shifter with the hood pulled forward.

Once the shifter is fully released, refit the cable and make sure it is fully engaged before refitting the shifter
VELOMANCER

Well that's the more blunt way of putting it but as usual he's dead right.

Re: New front shifter jammed/not pulling?
« Reply #6 on: 15 June, 2017, 11:38:45 am »
it is as well to note that it is also possible for the lube to dry out in 'new' shifters if they have been hanging around a while.  This means that (for example) the index mechanism won't always return by itself (i.e. under the tension of the internal spring as per the suggestion above) it may need to be helped, e.g. pulled round using the cable.

The other (related) fault which is  common to shifters of this type is that one or more pawls inside the unit are sticky enough that they won't engage. This can cause the symptoms you report too.

The 'cure' is usually to use a thinner penetrating lube on the shifter internals to free them up and then to use a thicker lube (like a spray semi-fluid grease) on them so that they are kept in good shape.  [IME if you try to use STIs with thin lube in them long-term they don't last well.]

cheers

Re: New front shifter jammed/not pulling?
« Reply #7 on: 15 June, 2017, 07:02:32 pm »
Take the cable out and work the inner lever so it is in the lowest position. Please note that the inner lever will sometimes not engage the shifter with the hood pulled forward.

Once the shifter is fully released, refit the cable and make sure it is fully engaged before refitting the shifter

 :thumbsup:  Cheers Torslanda, think that's done the trick.

I peeled back the hood, and could see that the cable end 'cylinder' was not in it's groove.   I had not checked whether the cable end was securely in place the first time around   :-[ something to remember.  So having detached the shifter, I pulled the cable out and worked the inner lever, replaced the cable (which was useful in itself) etc etc.  Thought... will it /won't it...  and it did! Shifted up to the large chain ring!   So here's hoping it's all good.

Now for the fine tuning and working out how trim adjustment helps...

Phil, I did try the bolt underneath the shifter, but it was tight.

Brucey,  thanks - must look into shimano lubricants. 
Cycle and recycle.   SS Wilson

Torslanda

  • Professional Gobshite
  • Just a tart for retro kit . . .
    • John's Bikes
Re: New front shifter jammed/not pulling?
« Reply #8 on: 16 June, 2017, 12:41:14 am »
You're welcome. Can add a new skillset. 'Divining problems by remote viewing'! 

That should look good on linkedin ;D
VELOMANCER

Well that's the more blunt way of putting it but as usual he's dead right.