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|
|/ \|

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

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/

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.

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.

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

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|
|/ \|

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.