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Old 05-26-09, 08:51 PM   #1
dtbaker61
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Drilling extraction hole in shifter to remove broken cable head stuck inside

I had a cable break just inside the cable end, and the end must have dropped inside a DA 7800 shifter. I cannot get the barrel to rotate so I can extract the cable end or install a new one...

Any tips on disassembly so as not to ruin it?
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Old 05-26-09, 08:55 PM   #2
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you can't get in there and just flick it out with a scribe or something?
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Old 05-26-09, 09:14 PM   #3
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tried... I cannot get the barrel to turn to expose the end. It is 'stuck' somewhere between and won't rotate.
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Old 05-26-09, 09:24 PM   #4
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makes you wish you had these, doesn't it?
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Old 05-26-09, 10:21 PM   #5
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I've got those, and smaller..... wife is an eye doctor. problem is that I cannot rotate the shifter barrel far enough to expose anything to grab. I fear that if I undo the front bolt the guts of the shifter will spring out. any helpful experience out there?
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Old 05-26-09, 10:28 PM   #6
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my guess is the cable end is frayed and caught between the shifter mech. and outer shell.

as for taking it apart...

Broken gear cable in Shimano 105 STI shifter
http://forums.bicycling.com/eve/foru...7/m/1251010095

is about all I could find.
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Old 05-27-09, 08:14 AM   #7
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yes, this is exactly the problem.... but I have NO frayed cable ends in sight to grab and pull. The shifters will move the barrel around the first 3 clicks, but then it is stuck and will not shift around to expose the cable hook. There must be frayed ends inside gumming it up, but nothing to grab.

I checked tech docs, but there is no info on disassembly of the shift body itself. I am guessing that once that front bolt comes off, everything is spring loaded and probably very tough to get back together without a lot of special tools...

so, any tips on how to rotate the shift barrel when NO cable is in sight?
or, can the body be disassembled and put back together by mortals?
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Old 05-27-09, 08:15 AM   #8
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who is your LBS? if you have a telephone number, I would like to call to see if they have any tricks...
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Old 05-27-09, 04:30 PM   #9
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I will say that you can do a lot of disassembly without getting anywhere. Probably the lead cable end is jammed. I tried various small tools and finally was able to snag a piece of cable while rotating the barrel and brought it to the surface. Prior to that I removed lots of small parts and I'll be lucky to put them back correctly. Good luck.
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Old 05-27-09, 04:37 PM   #10
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Use the smaller shift lever to rotate the mechanism back to its starting position. This should expose the cable end. I'm assuming that you will have to use a bit of force to make it rotate.

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Old 05-27-09, 04:47 PM   #11
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Use the smaller shift lever to rotate the mechanism back to its starting position. This should expose the cable end. I'm assuming that you will have to use a bit of force to make it rotate.

Al
the problem is that the barrel needs to rotate as if you are shifting to a larger gear, which relies on the rear d to 'pull' the cable... and it is stuck. I have no cable in sight to pull, and it is really stuck. I cannot get the thing to rotate to expose the starting position. ;(

I have tried prying on the inside pulley surface with a carbide scribe, tried pulling through a cable with an end crimped on, etc, etc. Cannot get the thing to rotate to the point where I can see or grab anything.
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Old 05-28-09, 11:29 AM   #12
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I am about to give up on attempts to rotate the cable end externally... I cannot think of any ways to force rotation past its current sticking point to expose the end. I have found references to a few people having succeeded in disassembly/re-assembly, but most seem to end in disaster and spring loaded pieces flying....

I am considering drilling a hole thru the outside brake handle body to (hopefully) expose the cable end in its current position... kinda shooting in the dark, so I thought i would run this by the group to see if anyone has tried this? Sounds crazy, but may be safer than attempting disassembly?!
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Old 05-28-09, 11:43 AM   #13
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Some tec docs that may help in taking it apart.
http://techdocs.shimano.com/media/te...9830625472.PDF

and
http://techdocs.shimano.com/media/te...9830609263.pdf
Good luck.
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Old 05-28-09, 11:51 AM   #14
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Some tec docs that may help in taking it apart.
http://techdocs.shimano.com/media/te...9830609263.pdf
Good luck.
nope.... these only take it down far enough to install cables and flightdecks... they do NOT explode the main lever assembly. As far as I have found, not even Shimano Certified shops are trained or qualified to take apart the main lever assy as they are apparently very difficult to put back together...
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Old 05-28-09, 12:43 PM   #15
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I have had the cable break twice, once on each 7800 shifters that I have, but never had your problem. Without seeing it, all I can suggest is to remove the lever from the bars, remove the brake hood, and see if that gives you some other options.

If that doesn't work, I wouldn't drill a hole in anything, period. I might try removing the brake lever pivot pin, I think it has a set screw to hold it in place. Don't try forcing anything. If you can see the little lead end, but can't pull it out, and want to live dangerous...a electronics soldering iron might melt the lead, just make sure were the molten lead runs doesn't do more damage...good luck
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Old 05-28-09, 12:55 PM   #16
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...suggest is to remove the lever from the bars, remove the brake hood, and see if that gives you some other options.
...If you can see the little lead end, but can't pull it out, and want to live dangerous...a electronics soldering iron might melt the lead,
nope, no end in sight... thats the problem. So far I am more inclined to try drilling than unbolting the main assy barrel bolt.
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Old 05-28-09, 02:40 PM   #17
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The Shimano levers can in fact be disassembled and put back together. It's tricky, but I mean, they were assembled in the first place, you know? The main challenge is re-seating the shift lever return springs. The trick is to use a loop of dental floss to guide the spring hook into its hole as you put the lever on.
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Old 05-28-09, 03:17 PM   #18
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at the shop where i once worked (still kinda do) we tried everything short of disassembling. turns out shimano covered under warranty. that's a common issue and they know it. no questions asked.
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Old 05-28-09, 05:55 PM   #19
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at the shop where i once worked (still kinda do) we tried everything short of disassembling. turns out shimano covered under warranty. that's a common issue and they know it. no questions asked.
used bike, no record of purchase date... you think they would still cover?


d
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Old 05-28-09, 05:55 PM   #20
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The main challenge is re-seating the shift lever return springs. The trick is to use a loop of dental floss to guide the spring hook into its hole as you put the lever on.
ahhhhhh, see now this gives me some hope......
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Old 05-28-09, 06:08 PM   #21
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Can you get something sorta pointy in the access/cable hole of the shifter housing to push the barrel around, or is there some part in there jamming things up? Even without the r der spring helping things out, if you're hitting the release lever while pushing through the little cable access window, it might move enough that you can gain purchase on the cable head or end.
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Old 05-28-09, 06:16 PM   #22
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Can you get something sorta pointy in the access/cable hole of the shifter housing to push the barrel around, or is there some part in there jamming things up?
nope, its really jammed in the middle. I have tried everything to get that sucker to rotate, it goes three clicks and thats it. No cable end or fragments in sight to grab.
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Old 05-28-09, 06:22 PM   #23
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The Shimano levers can in fact be disassembled and put back together. It's tricky, but I mean, they were assembled in the first place, you know? The main challenge is re-seating the shift lever return springs. The trick is to use a loop of dental floss to guide the spring hook into its hole as you put the lever on.
Bear in mind that they are assembled by robots.
I once watched an 8sp shifter taken apart by the head mechanic at a shop my friend owned and unless you have the skills of a watchmaker a lot can fly in your face.
Way I look at it though, you have a shifter that isn't going to work unless you perform emergency surgery on it. So scrub up, settle in, and be methodical and slow.
Oh yeah! Take pictures for us to see what the insides look like.
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Old 05-29-09, 04:30 AM   #24
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used bike, no record of purchase date... you think they would still cover?


d
man, that's a bummer. its worth a shot, just remove the shifter and take it in. but just be sure they're an official Shimano dealer. that makes a difference. the issue you describe sounds like the worst case scenario. sometimes you can fiddle with them and get that cable end out, but once it gets jammed inside the lever....its pretty much finished.
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Old 06-04-09, 09:35 PM   #25
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ok people... I was disheartened by all the stories of failed disassembly/reassembly, so tried a different approach. Since it actually WORKED and was a 10 minute fix I thought I would post it!

After close examination, and what turned out to be a really good guess, I decided to try drilling an 'extraction hole' in the shifter body over where I hoped the cable end was stuck to allow me to pull out the cable end from its stuck position.

First, I shifted 'down' to what would be the largest cog on the rear derailleur to force the cable end around to what I hoped was a known position. I took a wild but calculated guess, and drilled a small pilot hole 1/4" down from the end of the cable slot on the INSIDE of the brake lever, in line with where I hoped the cable end was. Then opened the hole up to 1/4".

Lo and behold, the cable end was right there! I used some skinny tweezers to grab the cable end and yanked that bad boy right out.

so... it IS possible to recover a stuck cable end from a worst case break! yippee..... question is why Shimano hasn't pre-drilled an access hole for this issue?!
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