Dura Ace 7400 Brifter Repair - Next Step??
#1
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Dura Ace 7400 Brifter Repair - Next Step??
I want to remove the large lever/housing, hoping that I'll be able to see what might be causing the shifting mechanism to not fully return to the small ring (downshifted) position. Trust me - I've tried every penetrant and lube that has ever been suggested for freeing up stuck shifters and that is definitely not going anywhere. I'm hoping that it's something obvious like a small piece of frayed cable that is fouling the mech rather than a broken spring or other part, but there's no way of knowing without getting the housing off. With other brifters that I've worked on, removing the small screw near the top/inside of the levers would let you slide the housing off but that doesn't seem to be the case with this one. I'm guessing I need to remove the notched, round nut on the back (first photo) of the shift assembly which requires a special tool, but don't want to go there if that is not the correct step, or worse - springs and small parts will fly everywhere. I can probably make the required tool by modifying an appropriate size socket, but if anyone has a better/simpler suggestion, please let me know.
I picked this left shifter up recently at a swap to match a working right DA 7400 shifter, gambling that it would be a simple matter of using some spray lube to get it working. The bike already has a working non-DA left brifter but I was hoping this would result in a matching set.
I picked this left shifter up recently at a swap to match a working right DA 7400 shifter, gambling that it would be a simple matter of using some spray lube to get it working. The bike already has a working non-DA left brifter but I was hoping this would result in a matching set.
#2
Full Member
I know the dura ace versions are a little different than the other brifters made in this time period but I am pretty sure you have everything right. The little screw on the back of the lever is usually all you need to remove. Are you sure it isn't just jammed on something?
Could you take a picture of the front of the shifter? Maybe that has a clue.
Could you take a picture of the front of the shifter? Maybe that has a clue.
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#4
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I've used a very small, slim Vise-Grip plier to loosen the castle nut on several occasions. It is slow going but will inch the nut along until you can grip it with needle-nose pliers and turn the nut a little further with each re-position of the jaws (because the needle-nose plier jaws are thinner). From there, it comes right off.
Oh, one more thing, apply a bit of penetrant first.
I would start taking notes, in order, as to how each piece fits, in which orientation.
I have found levers where the tip of the small lever had sheared off, just above the pivot (where it is now still not visible). Usually this is on the right lever however.
Keep an eye out for any tiny broken-off bits that are part of the rotating plates inside.
Good news (if you can't fix this one) is that left levers should be much easier to source.
Oh, one more thing, apply a bit of penetrant first.
I would start taking notes, in order, as to how each piece fits, in which orientation.
I have found levers where the tip of the small lever had sheared off, just above the pivot (where it is now still not visible). Usually this is on the right lever however.
Keep an eye out for any tiny broken-off bits that are part of the rotating plates inside.
Good news (if you can't fix this one) is that left levers should be much easier to source.
#5
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#6
Junior Member
Thread Starter
I've used a very small, slim Vise-Grip plier to loosen the castle nut on several occasions. It is slow going but will inch the nut along until you can grip it with needle-nose pliers and turn the nut a little further with each re-position of the jaws (because the needle-nose plier jaws are thinner). From there, it comes right off.
Oh, one more thing, apply a bit of penetrant first.
I would start taking notes, in order, as to how each piece fits, in which orientation.
I have found levers where the tip of the small lever had sheared off, just above the pivot (where it is now still not visible). Usually this is on the right lever however.
Keep an eye out for any tiny broken-off bits that are part of the rotating plates inside.
Good news (if you can't fix this one) is that left levers should be much easier to source.
Oh, one more thing, apply a bit of penetrant first.
I would start taking notes, in order, as to how each piece fits, in which orientation.
I have found levers where the tip of the small lever had sheared off, just above the pivot (where it is now still not visible). Usually this is on the right lever however.
Keep an eye out for any tiny broken-off bits that are part of the rotating plates inside.
Good news (if you can't fix this one) is that left levers should be much easier to source.
In looking at the shifting mech, I can see a very thin shim that was apparently jammed and got deformed, but I think the actual problem is deeper inside where all the gears/pawls/springs are. Debating if I want to go there since I know how you reach a point where you remove something and all of a sudden a lot of tiny parts unexpectedly fall out. On the other hand, it's not worth anything the way it is other than for parts, so not much to lose. A project better left for a bad-weather day because I know it won't be quick.
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Ok, at this point you want to be sure that you have all reassembly steps documented, in order.
Then we need to see what the pivot end of the small lever looks like, removed.
I'm suspecting there might be no reason to take the "barrel" assembly apart.
Then we need to see what the pivot end of the small lever looks like, removed.
I'm suspecting there might be no reason to take the "barrel" assembly apart.
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I have One DuraAce 8 speed integrated lever that flops.
got the bike that way.
I have not yet bothered to take it apart as I figure something is broken, and parts? Not like Campagnolo that for a good chunk of time had replacement parts.
got the bike that way.
I have not yet bothered to take it apart as I figure something is broken, and parts? Not like Campagnolo that for a good chunk of time had replacement parts.
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Those were SO notorious for cable insertion errors. Your symptom sounds like that, and 90% of the ones I've worked on were simply that, or a subsequent loose evil piece of cable due to that.
Only one, ever, didn't respond to simple disassembly and reassembly. Out of maybe 10-12, from SLX to DA. I punted on that one. I have limits.
Only one, ever, didn't respond to simple disassembly and reassembly. Out of maybe 10-12, from SLX to DA. I punted on that one. I have limits.