7800 shifter rebuilt

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odin99
Posts: 187
Joined: Wed Feb 16, 2011 7:46 pm

by odin99

anyone take a part and rebuild a 7800 shifter?

one of mine stopped working after my bike fell over. i'd call it a crash, but i wasn't on the bike. doh.

any advice / know how out there?

CerveloMikey
Posts: 80
Joined: Tue Sep 16, 2008 11:20 pm
Location: Burbank, CA

by CerveloMikey

What are the symptoms? If it is not clicking and the lever is just swinging, try spraying some automotive brake cleaner into it. Most of the time they are just gummed up by the Shimano factory grease. Once you get it working again, squeeze in some Prolink chain lube and you will be good to go.
R2.5 / R3 / S-Works 29er (20 lbs) / S-Works SL4 Di2 (14.7 lbs)

odin99
Posts: 187
Joined: Wed Feb 16, 2011 7:46 pm

by odin99

the small lever does not engage. it stick in the 'big ring' and won't down shift. the larger lever seems to work fine.

it isn't sticky... something is either broken or caught.

CerveloMikey
Posts: 80
Joined: Tue Sep 16, 2008 11:20 pm
Location: Burbank, CA

by CerveloMikey

Mine was doing the exact same thing. Shimano recommends taking it off the bar and soaking it in a "gentle" degreaser over night. I left it on the bar, used a toe strap to hold it open and sprayed the shit out of it with CRC Brakeclean. After a couple sessions it worked fine. Try it, what have you go to lose? Might be a coincidence that it stuck after the fall. The factory Shimano grease turns to gorilla snot and won't let it release.
R2.5 / R3 / S-Works 29er (20 lbs) / S-Works SL4 Di2 (14.7 lbs)

eric
Posts: 2196
Joined: Tue Nov 11, 2003 9:47 pm
Location: Santa Cruz, California, USA
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by eric

You did make sure that the cable is not fraying inside the lever, right?

Pull the brake and shine a light through the cable access hole. If it's fraying you can often see it. You may need to shift to the large end of the cassette.

If in doubt change the cable. 7800 shifters break cables pretty quick. I get about 2500-3000 miles out of mine.

odin99
Posts: 187
Joined: Wed Feb 16, 2011 7:46 pm

by odin99

i don't think its a coincidence it stopped working after it fell. it was never sticky before it fell - no issues until immediately after. I'll try to spray any gummed grease from the inside, but again, i don't think thats the problem. I've had shifters with this problem before and this isn't the same.

I've removed it from the bike and removed the cable. same problem. I can see where the cable goes through - there's no frayed end or anything stuck inside.

so no one's actually taking one of these things apart?

quattrings
Posts: 482
Joined: Sun Nov 14, 2010 10:25 pm

by quattrings

sure, I've taken one apart, but it's difficult getting to the shifting internals and I wouldn't recommend it. Shimano sell the shifter assembly as part of a rebuild kit. this kit wil have the internals and levers included as one piece. swapping the parts will take you roughly 10 minutes. I believe it only requires you to remove cables and the lever pivot bolt.

I once had the link from a store selling the lever assembly but I can't seem to dig it up at the moment.
Edit:
you would need part 1a & 1b for the rebuild
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