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#1
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dismantled my Shimano Nexus 8 hub
.... and I haven't got any bits left over after putting it back
together! However, it was in a most horrible state internally, and having heard that before (here, I think) I thought I'd pass on the warning - the seals are not as good as they might be. This despite me having the one with the red ring that's supposed to be better seals and bearings. In particular, there's a very big ball-race just inside the big plastic cap on the drive side. You can see it on step 6 he http://www.sheldonbrown.com/nexus8/pages/13.htm Mine (about 20 months of daily commuting, but lives indoors at home and under cover at work) is not that shiny. In fact, it was brown and cruddy and the bearings look like lead shot and both cup and cone are decidedly nasty. Things were so bad, balls were falling out of the retainer even when it was sitting on the cone - I think (hope) that's loss of section from the retainer rather than loss of diameter from the balls. However, the useful thing to know is that you can see the state of this race without a full dismantle (ie, to decide whether to dismantle or not). 1: take wheel out 2: remove the 'cassette joint' and 'driver cap' (reverse of the instructions he http://www.sheldonbrown.com/nexus8/pages/06.htm ) Note the driver cap is just a plastic ring that's a push fit - you can prise it off with fingers (or gently with a flat screwdriver) 3: remove the spring-clip and the sprocket (this is the only difficult step). 4: I'm pretty sure the big plastic 'right dust cap' will now just pull off, but it might want some gentle prising with a sharp blade round the periphery. If you look at the shimano service manual (courtesy of St S B) you can see that the 'official' sequence is to dismantle the left side bearing, pull the whole gubbins out the right (pulling the cap out of the hub shell as you do so) and then lift the cap off the gubbins, so my sequence ought to work. You will now find you can see the ball-carrier. That is, the end of the gubbins will be visible, a thin ring of ball carrier, then the edge of the hub shell (which has the cup pressed into it). If your hub is in as bad a state as mine, you will now be seeing lots of brown crud where a shiny ball carrier should be. I also found the mid-hub roller bearings (in the left hand in picture 6 here http://www.sheldonbrown.com/nexus8/pages/13.htm was similarly cruddy, but you need to follow the dismantle instructions to get to that. The top picture here, some way into the dismantle, shows the ball retainer being lifted off the gubbins, and the cone is visible. http://www.sheldonbrown.com/nexus8/pages/15.htm (Step 10 is where I stopped - at that point you can get grease into most parts, the next bit is the right-hand cup and cone which I could see was ok, and step 16 looks scary so I didn't proceed further). regards, Ian SMith -- |\ /| no .sig |o o| |/ \| |
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#2
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dismantled my Shimano Nexus 8 hub
On 21 Sep 2008 19:27:45 GMT, Ian Smith said
in : ... and I haven't got any bits left over after putting it back together! But did you find the ping****it clip? Guy -- May contain traces of irony. Contents liable to settle after posting. http://www.chapmancentral.co.uk 85% of helmet statistics are made up, 69% of them at CHS, Puget Sound |
#3
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dismantled my Shimano Nexus 8 hub
On 21/09/2008 21:04, Just zis Guy, you know? said,
But did you find the ping****it clip? It was under the fridge :-) -- Paul Boyd http://www.paul-boyd.co.uk/ |
#4
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dismantled my Shimano Nexus 8 hub
Ian Smith wrote:
... and I haven't got any bits left over after putting it back together! However, it was in a most horrible state internally, and having heard that before (here, I think) I thought I'd pass on the warning - the seals are not as good as they might be. This despite me having the one with the red ring that's supposed to be better seals and bearings. In particular, there's a very big ball-race just inside the big plastic cap on the drive side. You can see it on step 6 he http://www.sheldonbrown.com/nexus8/pages/13.htm Mine (about 20 months of daily commuting, but lives indoors at home and under cover at work) is not that shiny. In fact, it was brown and cruddy and the bearings look like lead shot and both cup and cone are decidedly nasty. Things were so bad, balls were falling out of the retainer even when it was sitting on the cone - I think (hope) that's loss of section from the retainer rather than loss of diameter from the balls. However, the useful thing to know is that you can see the state of this race without a full dismantle (ie, to decide whether to dismantle or not). 1: take wheel out 2: remove the 'cassette joint' and 'driver cap' (reverse of the instructions he http://www.sheldonbrown.com/nexus8/pages/06.htm ) Note the driver cap is just a plastic ring that's a push fit - you can prise it off with fingers (or gently with a flat screwdriver) 3: remove the spring-clip and the sprocket (this is the only difficult step). 4: I'm pretty sure the big plastic 'right dust cap' will now just pull off, but it might want some gentle prising with a sharp blade round the periphery. If you look at the shimano service manual (courtesy of St S B) you can see that the 'official' sequence is to dismantle the left side bearing, pull the whole gubbins out the right (pulling the cap out of the hub shell as you do so) and then lift the cap off the gubbins, so my sequence ought to work. You will now find you can see the ball-carrier. That is, the end of the gubbins will be visible, a thin ring of ball carrier, then the edge of the hub shell (which has the cup pressed into it). If your hub is in as bad a state as mine, you will now be seeing lots of brown crud where a shiny ball carrier should be. I also found the mid-hub roller bearings (in the left hand in picture 6 here http://www.sheldonbrown.com/nexus8/pages/13.htm was similarly cruddy, but you need to follow the dismantle instructions to get to that. The top picture here, some way into the dismantle, shows the ball retainer being lifted off the gubbins, and the cone is visible. http://www.sheldonbrown.com/nexus8/pages/15.htm (Step 10 is where I stopped - at that point you can get grease into most parts, the next bit is the right-hand cup and cone which I could see was ok, and step 16 looks scary so I didn't proceed further). regards, Ian SMith Messrs Sturmey and Archer got it right in 1902. An old AW rarely lets in water, and it's all done without any plastic or rubber seals. If it all goes pear-shaped, every internal part is available for a very small cost. (OK, they also weep oil constantly, but if you tighten the RH ball ring properly it's a minimal amount). Still, I suppse you can stand on the Nexus in top gear without the clutch squirming off the planet pins and dropping you into "neutral" without warning - something SunRace have fixed these days, at the expense of another set of pawls. |
#5
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dismantled my Shimano Nexus 8 hub
Just zis Guy, you know? wrote:
On 21 Sep 2008 19:27:45 GMT, Ian Smith said in : ... and I haven't got any bits left over after putting it back together! But did you find the ping****it clip? I don't see the first post, probably because of the cream cheese Tiscali use for copper. Could we have a bit of info on how diffilcult it was, instructions for those about to try, recommendations that aren't, how shall we say, in line with the manufacturers guidelines. |
#6
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dismantled my Shimano Nexus 8 hub
Ian Smith writes:
... and I haven't got any bits left over after putting it back together! However, it was in a most horrible state internally, and having heard that before (here, I think) I thought I'd pass on the warning - the seals are not as good as they might be. This despite me having the one with the red ring that's supposed to be better seals and bearings. Thanks, saved for future reference. Mine (also red ring) has now been in use for 4 months so I probably still have some time to go. Roos |
#7
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dismantled my Shimano Nexus 8 hub
On Sun, 21 Sep 2008, Tosspot wrote:
Just zis Guy, you know? wrote: On 21 Sep 2008 19:27:45 GMT, Ian Smith said in : ... and I haven't got any bits left over after putting it back together! But did you find the ping****it clip? I don't see the first post, probably because of the cream cheese Tiscali use for copper. Could we have a bit of info on how diffilcult it was, instructions for those about to try, recommendations that aren't, how shall we say, in line with the manufacturers guidelines. It's on google groups if you look for it. I followed the service manual sequence, courtesy of the copy on Sheldon Brown's web site (links in previous message). It was mostly very easy (at least as far as I went - I stopped before the stage that requires special tools and press-fit to re-assemble). By far the most difficult step is the snap ring holding the sprocket on - it's a circlip but without holes for circlip pliers or lugs to provide levering points. I triumphed by using circlip pliers with the prongs just bearing on the ends of the clip - one hand holding the jaws in place, one hand closing the pliers handles, one hand ready to jab a screwdriver in the gap as soon as it appeared, one hand holding a cloth over the whole lot to catch the clip should it try and fly off and a final hand with the first-aid kit in case any of the other hands got stabbed by the screwdriver and/or pliers prongs while levering under cover of the cloth. At least, that's the method I would have adopted had I been equipped with the same number of arms as whoever planned to take it apart. The only other unclear step is when the manual says pull the gubbins out - it really does just pull out, the big plastic cap is just a push fit (by hand) into the end of the shell. My only suggestion would be to do the partial dismantle from the plastic cap end (as described in my original post) to get sight of the big bearing and decide whether you need to open it up. regards, Ian SMith -- |\ /| no .sig |o o| |/ \| |
#8
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dismantled my Shimano Nexus 8 hub
Ian Smith wrote:
On Sun, 21 Sep 2008, Tosspot wrote: Just zis Guy, you know? wrote: On 21 Sep 2008 19:27:45 GMT, Ian Smith said in : ... and I haven't got any bits left over after putting it back together! But did you find the ping****it clip? I don't see the first post, probably because of the cream cheese Tiscali use for copper. Could we have a bit of info on how diffilcult it was, instructions for those about to try, recommendations that aren't, how shall we say, in line with the manufacturers guidelines. It's on google groups if you look for it. I followed the service manual sequence, courtesy of the copy on Sheldon Brown's web site (links in previous message). It was mostly very easy (at least as far as I went - I stopped before the stage that requires special tools and press-fit to re-assemble). By far the most difficult step is the snap ring holding the sprocket on - it's a circlip but without holes for circlip pliers or lugs to provide levering points. I triumphed by using circlip pliers with the prongs just bearing on the ends of the clip - one hand holding the jaws in place, one hand closing the pliers handles, one hand ready to jab a screwdriver in the gap as soon as it appeared, one hand holding a cloth over the whole lot to catch the clip should it try and fly off and a final hand with the first-aid kit in case any of the other hands got stabbed by the screwdriver and/or pliers prongs while levering under cover of the cloth. At least, that's the method I would have adopted had I been equipped with the same number of arms as whoever planned to take it apart. The only other unclear step is when the manual says pull the gubbins out - it really does just pull out, the big plastic cap is just a push fit (by hand) into the end of the shell. My only suggestion would be to do the partial dismantle from the plastic cap end (as described in my original post) to get sight of the big bearing and decide whether you need to open it up. Many thanks, I have a new one, but it's always nice to know you can take them apart and fix them. |
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