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Nexus 8 overhaul problem

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  • joavrage
    Oh, boy, I ve really done it. I m overhauling my Nexus 8 speed Red Band SG-8R36. I dunked it in ATF two years ago and I want to get the break-in wear particles
    Message 1 of 4 , Jul 4, 2013
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      Oh, boy, I've really done it.

      I'm overhauling my Nexus 8 speed Red Band SG-8R36. I dunked it in ATF two years ago and I want to get the break-in wear particles out of the grease before something bad happens. It's currently in great shape and I intend to keep it that way.

      As I was attempting to separate the ring gear from the carrier, I found a C-clip on the opposite end (the smaller roller clutch end). Thinking this was the way, I popped it off only to discover that it held the roller clutch together. No problem (once I got the rollers back in!), except there's a return spring - one end fits in the carrier, the other end fits somewhere on the plastic  roller retainer. There's an indent on the retainer, but I can't figure out how to hook the spring on it.

      Anyone ever run across this before? And how exactly do you open the carrier to remove the ring gears on this model? 


      Thanks in advance,

      J.

    • joavrage
      I think I may have solved the problem. When I popped off the retainer ring, the spring flipped over to the other side. By manipulating the other roller
      Message 2 of 4 , Jul 5, 2013
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        I think I may have solved the problem.

        When I popped off the retainer ring, the spring flipped over to the other side. By manipulating the other roller clutches, I figured out that the spring had to be reversed, judging by the shape of the insertion point on the plastic roller retainer. It now operates the same way and with the same spring tension as the other clutches. Keeping my fingers crossed, here...

        In the pic, you can see the round and square ends of the spring installed as I think it ought to go. I'm a little leery of the square end as it looks strange to me. I tried it both ways, and this made the most sense.

        So I'll snap the circlip back in place and keep my fingers crossed. Lesson learned - DON'T MESS WITH THAT END OF THE HUB INTERNALS!!

        If anyone has any wisdom to share, I'd be glad to hear it, thanks!


      • Ian
        ... Last year I posted this on the Moulton Yahoo group. All I can think to is pay attention when you are taking things apart and pretty much everything will
        Message 3 of 4 , Jul 5, 2013
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          --- In Geared_hub_bikes@yahoogroups.com, "joavrage" <joavrage@...> wrote:
          >
          > Lesson learned - DON'T MESS WITH THAT END OF THE HUB INTERNALS!!
          > If anyone has any wisdom to share, I'd be glad to hear it, thanks!

          Last year I posted this on the Moulton Yahoo group. All I can think to is 'pay attention' when you are taking things apart and pretty much everything will go back together if you look at it for long enough!

          Anyway back in August last year......

          ***

          Once the rain stopped this morning I had some errands to run, go out to garage and found the rear tyre was flat. Thought it had felt a bit odd on the last bit of ride home the other day and that explains it. So did the errands on the motorcycle.

          Once I got back I set to on the TSR, bike up on stand, wheel out (a bit more of a palaver with the rear drum than with caliper brakes, but I'm a dab hand at it now) and pulled the tube out.

          Puncture duly fixed (and tear in sidewall noted - better get some new tyres) and a mate turned up. He was in a chatty mood so a back to the garage with a cuppa and he wondered what was inside the 8-speed hub. Since the wheel was out, I had got some small circlip pliers and had it apart the other day it was no matter, I could show him and lube it up at the same time, so I pulled the snap ring and sprocket off loosened the nut on the drive side, thought -

          "This is wrong, it's the brake side I have to loosen", flipped it over, took off the brake and l/h cone knocked the ball ring round and pulled out the gearbox.

          'PING!' went a spring inside.

          F*%k! went I.

          Turns out if the r/h cone is loose the internals can move about a bit - and had. A bit of head scratching and careful looking at the parts drawing suggested buy pulling it out I had separated the return spring from the gear selector. Shows that you should not be chatting when doing stuff like this - even if you think you know what you are doing! Mate made his excuses and left!

          Well, what man put together and pulled apart can be reassembled. I had to extricate the various gear ring assemblies and it took me about an hour to work out how to reassemble the shift actuator although it is quite easy once you identify the cams and get them lined up. Reassembled the gear rings, built up the hub and decided that the spring should have more tension so disassembled and did it again with more tension on the spring. Discovered I had 8 gears (hurrah!) so pulled it all apart again and reassembled with plenty of EP0 grease.

          Assembly is the reverse of the dismantle, check the gears on the stand. All good. Quick spin up the road and the 'pursued by bees' buzz is definitely reduced.

          Important - those who have recent Sturmey hubs, I would suggest they are not overly well lubricated from the factory and you to can have a humorous and educational afternoon pulling them apart and learning how they work before greasing them up and reassembly!

          ***

          Hope that helps!

          Ian
        • joavrage
          @ Ian - So true, so true. Everything WILL go back together. Your story reminds me of when I built this same wheel. I went to a buddy s shop with my
          Message 4 of 4 , Jul 5, 2013
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            @ Ian -

            So true, so true. Everything WILL go back together.

            Your story reminds me of when I built this same wheel. I went to a buddy's shop with my wheelbuilding tools, as he and some friends were interested in the procedure.

            Well, the wheel got built, but it took forever. I kept getting distracted as I explained things. The beer didn't help either (well, it did, but...). When I got it home, I had to retension it. Lesson learned there, too.

            I finished tearing down the hub this morning. Washed everything with solvent, dried and reassembled with some leftover Nexus grease from another hub I had done. Dunked the assembly in synthetic ATF, let drip for a few minutes and finished assembly.

            Back on the bike, while on the stand the hub performed flawlessly. What a relief! I don't have time to ride it today but I'm fairly sure it should perform well under load as well.

            I'd like to try Aaron's Tenacious Oil/marine grease combo next time. ATF is just too thin for this application. The hub will drip for a few weeks after the overhaul. I have to be careful to keep a piece of cardboard handy when I park it inside.

            Anyway, lesson learned, be careful and pay attention!

            Thanks for the insight.

            Cheers,

            J.

            --- In Geared_hub_bikes@yahoogroups.com, "Ian" <fjsrider@...> wrote:
            >
            > --- In Geared_hub_bikes@yahoogroups.com, "joavrage" <joavrage@> wrote:
            > >
            > > Lesson learned - DON'T MESS WITH THAT END OF THE HUB INTERNALS!!
            > > If anyone has any wisdom to share, I'd be glad to hear it, thanks!
            >
            > Last year I posted this on the Moulton Yahoo group. All I can think to is 'pay attention' when you are taking things apart and pretty much everything will go back together if you look at it for long enough!
            >
            > Anyway back in August last year......
            >
            > ***
            >
            > Once the rain stopped this morning I had some errands to run, go out to garage and found the rear tyre was flat. Thought it had felt a bit odd on the last bit of ride home the other day and that explains it. So did the errands on the motorcycle.
            >
            > Once I got back I set to on the TSR, bike up on stand, wheel out (a bit more of a palaver with the rear drum than with caliper brakes, but I'm a dab hand at it now) and pulled the tube out.
            >
            > Puncture duly fixed (and tear in sidewall noted - better get some new tyres) and a mate turned up. He was in a chatty mood so a back to the garage with a cuppa and he wondered what was inside the 8-speed hub. Since the wheel was out, I had got some small circlip pliers and had it apart the other day it was no matter, I could show him and lube it up at the same time, so I pulled the snap ring and sprocket off loosened the nut on the drive side, thought -
            >
            > "This is wrong, it's the brake side I have to loosen", flipped it over, took off the brake and l/h cone knocked the ball ring round and pulled out the gearbox.
            >
            > 'PING!' went a spring inside.
            >
            > F*%k! went I.
            >
            > Turns out if the r/h cone is loose the internals can move about a bit - and had. A bit of head scratching and careful looking at the parts drawing suggested buy pulling it out I had separated the return spring from the gear selector. Shows that you should not be chatting when doing stuff like this - even if you think you know what you are doing! Mate made his excuses and left!
            >
            > Well, what man put together and pulled apart can be reassembled. I had to extricate the various gear ring assemblies and it took me about an hour to work out how to reassemble the shift actuator although it is quite easy once you identify the cams and get them lined up. Reassembled the gear rings, built up the hub and decided that the spring should have more tension so disassembled and did it again with more tension on the spring. Discovered I had 8 gears (hurrah!) so pulled it all apart again and reassembled with plenty of EP0 grease.
            >
            > Assembly is the reverse of the dismantle, check the gears on the stand. All good. Quick spin up the road and the 'pursued by bees' buzz is definitely reduced.
            >
            > Important - those who have recent Sturmey hubs, I would suggest they are not overly well lubricated from the factory and you to can have a humorous and educational afternoon pulling them apart and learning how they work before greasing them up and reassembly!
            >
            > ***
            >
            > Hope that helps!
            >
            > Ian
            >
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