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Re-assembly Shimano 7800 Brifter?

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Re-assembly Shimano 7800 Brifter?

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Old 01-13-18, 11:32 PM
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vintagerando 
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Re-assembly Shimano 7800 Brifter?

Hi. My left (front derailleur) brifter was not shifting. I removed the black plastic housing and sprayed a ton of WD 40. It now shifts perfectly. Problem is I cannot re-assemble the black housing and coil piece. The coil needs to "compress" into the plastic housing piece. There is a screw and a small nut to hold it in place. After many attempt to compress the coil into the interior of the black housing, and affix the screw and bolt, I finally got it fit back together. Now the lever sticks when shifted. So, the coil is not compress enough or is mis-aligned. What it the correct procedure to re-assemble this? What am I missing? Thanks.
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Old 01-14-18, 02:14 AM
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Well at least it was you who took it apart and you know how you did it.
You will have to try again and see if you can learn how to do it properly.
From what i have seen these are not serviceable items and you may struggle.
Keep trying and you may succeed.
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Old 01-14-18, 07:44 AM
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I think you are done with it. A friend and I tried this and gave up after hours of frustration. It's a shame, love 7800.
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Old 01-14-18, 07:50 AM
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Shimano brifters normal repair is to buy a new one and that has been true since they first appeared in the 1990s. Roger
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Old 01-14-18, 01:45 PM
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I'm not throwing in the towel yet, someone out there has done this, just got to find him.
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Old 01-14-18, 07:33 PM
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Maybe Pm user QuangVuong. He's done guides for rebuilding Shimano brifters.This spring looks similar to those found in the 6400 and RSX units.GUIDE: Repairing Shimano RSX (A410) STI Levers
GUIDE: Repairing Shimano 600 (6400) STI Levers

Photos available here. http://www.bicycles.net.au/forums/vi...p?f=34&t=65831

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Old 01-15-18, 12:10 AM
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Originally Posted by darkhorse75 View Post
Maybe Pm user QuangVuong. He's done guides for rebuilding Shimano brifters.This spring looks similar to those found in the 6400 and RSX units.GUIDE: Repairing Shimano RSX (A410) STI Levers
GUIDE: Repairing Shimano 600 (6400) STI Levers

Photos available here. GUIDE: Repairing Shimano 600 (6400) STI Levers - Australian Cycling Forums - Bicycles Network Australia
Thanks for the info. I PMed QuangVuong.
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Old 01-15-18, 01:56 AM
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Originally Posted by vintagerando View Post
I'm not throwing in the towel yet, someone out there has done this, just got to find him.
RJ the Bike Guy on Youtube has a couple of video on brifter repairs.


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Old 01-15-18, 07:50 AM
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I overhauled a pair of these a couple of months ago. Iirc it's quite a struggle on this particular model to get that damn spring back in properly; I have mad skills with STIs and it took me a frustrating number of attempts, maybe 15 or 20 minutes.

Basically, with this bit you have to put the spring in the cover and ensure it's properly seated, and then carefully hook the free end of the spring into its hole on the lever - at this point the cover is on an angle (viewed from the front rather than the side) - and then you need to rotate the cover into position while pushing it against the lever, winding up the spring. It's difficult to manage without the spring popping slightly out of place, which causes the jamming.

Just have patience (a dose of weed might help if you partake), and you should get there in the end. Worst case scenario, the lever still pretty much works without that spring.
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Old 01-15-18, 09:35 PM
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Originally Posted by Kimmo View Post
I overhauled a pair of these a couple of months ago. Iirc it's quite a struggle on this particular model to get that damn spring back in properly; I have mad skills with STIs and it took me a frustrating number of attempts, maybe 15 or 20 minutes.

Basically, with this bit you have to put the spring in the cover and ensure it's properly seated, and then carefully hook the free end of the spring into its hole on the lever - at this point the cover is on an angle (viewed from the front rather than the side) - and then you need to rotate the cover into position while pushing it against the lever, winding up the spring. It's difficult to manage without the spring popping slightly out of place, which causes the jamming.

Just have patience (a dose of weed might help if you partake), and you should get there in the end. Worst case scenario, the lever still pretty much works without that spring.
Awesome...I found someone who has fixed one of these! Did you hold the black/plastic housing piece at 90 degrees or hold it aligned in the way it will go on? I was able to compress the coil and get the black/plastic housing piece back on, but the lever would stick in the "shifting position." So, I figured the coil in backwards? I flipped the coil and tried again. Just cannot get it compressed enough to get the screw in or nut on. Do you hold it with the lever facing you, as it front of the bike if it were attached to the handelbars? Are you twisting and pressing it down with the black/plastic piece in the 12 o'clock position? Or 6 or 9 o'clock position? Thanks.
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Old 01-18-18, 01:07 AM
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Originally Posted by vintagerando View Post
Awesome...I found someone who has fixed one of these! Did you hold the black/plastic housing piece at 90 degrees or hold it aligned in the way it will go on? I was able to compress the coil and get the black/plastic housing piece back on, but the lever would stick in the "shifting position." So, I figured the coil in backwards? I flipped the coil and tried again. Just cannot get it compressed enough to get the screw in or nut on. Do you hold it with the lever facing you, as it front of the bike if it were attached to the handelbars? Are you twisting and pressing it down with the black/plastic piece in the 12 o'clock position? Or 6 or 9 o'clock position? Thanks.
I can't remember if the spring is the same on each end (some aren't), but you should be able to figure it out from close examination. You need to make sure it's all the way in the cover first, then when you put it on you just line it up on whatever angle the free end of the spring dictates. It's probably best to do it from in front of the lever.
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Old 01-20-18, 07:22 PM
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Originally Posted by vintagerando
If you hold the lever looking from the front, place the black/plastic housing piece at 9 o'clock and turn clockwise? Or hold the black/plastic at 3 0'clock and turn counter-clockwise? Man, this is a tough one. I appreciate any help. Thanks.
First, take a good look at the spring. It kinda springs both ways, but it's only supposed to go to one side of its resting position. With virtually every such spring that operates in torsion around the axis of its coils, that direction is the one which shrinks the coils. If you've forced that spring too far the wrong way, you may have buggered your chances of getting it in properly.

It can be deduced from your pics - looking at the lever from the front, the spring needs to be wound anticlockwise. From memory it should be something like 1/4-1/3 of a turn; if it's much more, you've probably tweaked the spring and are in trouble.

But the angle you need to wind it isn't a prescribed thing as such; it should be plain because it's dictated by where you have to hook the end of the spring in the lever. You can't just pick one of those holes; they're speed holes aka drillium. The proper hole is different; I'd say it's the small one at 9 o'clock.
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