rodar y rodar

Okay- I searched and found a lot of info on Nexus hubs, but little that will help me with my specific issue. Here`s my situation: I`ve been running my Redband 8 for ~2 years, maybe 3000 miles. I don`t have any real problems, just want to keep it in good shape and I see that Shimano now recomends occasional relubing and cone replacement.

I tried to disassemble my hub today according to the online tech manual, but didn`t get very far. The next step after pulling the shell off is flip the hub over and remove a dust seal from the drive side. (Step six here: https://bike.shimano.com/publish/cont...08%20ohaul.pdf)
It doesn`t want to come off and I don`t want to bend anything or screw it up just to keep it from getting screwed up in the future. The instructions are for the 8R20 and I think mine is the 8R25, but it looks the same so far, so I THINK that`s still the way I need to go. Anybody done this? Since a good part of the mechanism is behind that seal, I think I really ought to get at it. Or maybe just force some grease into the works?

Anyway, that was today`s show stopper. I`ll likely run into more if I get past it. And while I`m in there, am I supposed to flush out the old grease (discolored, but still not gummy) before I relube? Any related tidbits of advice appreciated. Thanks.

Panthers007

I'd take it to a shop that handles these hubs and let them tackle it. And ask to watch - of course.

rodar y rodar

I haven`t called my local shops, but I kind of doubt they do it. Never know, though. BTW, I just plan to clean and lube this time since I think the cones and balls are still fine for another 3K. Does that sound reasonable?

Panthers007

Just this:

Never mind the shop-rag for laying down the parts on in the correct sequence. Get out a beach-towel. Try very hard not to lose anything. Planetary-hubs are well known for launching things into orbit.

I've never taken apart a Shimano internal-gear hub - but I have taken down a Sturmey-Archer to replace some pawls. Wow! Glad I used a long, white sheet of tracing-paper. Let us know how it goes.

Dan Burkhart 

Removing the dust cover is not necessary, although it should slip off without too much trouble.
Unless you have some special tools, you should not proceed beyond step 8 of that document.The carrier unit does need to come off in order to remove the bearing retainer. It comes off as a unit,and you don't have to worry about little parts flying everywhere.
This is true of later production 7 speeds and all 8 speeds. Early production 7 speeds were a bit more complicated.
Going beyond step 8 is more for repair and parts replacement than for periodic maintenance anyway.
Shimano now has an oiling kit for lubing the internals. The bearings still need to be greased with the special Nexus grease, but for the mileage you are putting on, oiling the internals would not be a bad idea.
I was at a Shimano repair clinic this past winter where they demonstrated the proceedure, and of course they want you to use their special oil, but I think any old ATF would work.
You simply dunk the internals,on end, in a can of oil,(no need to degrease or anything first) then turn it on it's side and let it drip out.
Enough oil will cling to it to do the job. Once a year should be good unless you are riding through a lot of really foul conditions.

reverborama

Yow -- I have 3500+ miles on my Nexus 8 redband. I guess I was going to ride it until it broke then worry about it!

badmother

Did you remember to remowe the circular spring + the sprocket on the drive side? I guess you did, but this is the only thing I can think of could be wrong at this stage.

I newer did a 8sp but did several 7 speeds.

First time I showed up in a shop with some broken pieces in a plasticbag to buy spares the bikemechanic said he newer looked innside one of those. There is quite a lot of them around here, but I think he price of having one serviced is more than buying a new one, so peopel just ride until it stops and then buy a new bike...

I think you should go ahead and try to learn this. There is a IGH group, I think at Yahoo (my computer is in for repair so my links are gone), do a search and you`ll find the link to that one and other webpages.

I think if you want to relube with grease you should get rid of the old gummed up grease. If you dip it in oil I think no need, unless you suspect sand or other stuff innside. I like the oil idea, several threads around the forums about oiling instead of greasing IGH`s, hoping for smoother running hubs with less friction.

Tell us about your progres.

tatfiend 

The link to the yahoo IGH group badmother mentioned is in my signature block below.

rodar y rodar

Thanks a million for the replies, all. I`m pretty sure I`m looking at the right part, although it`s awfull heavy duty to be called "dust cover" (more like a structural part of the hub to me), and it also seems to serve as the cone for a large diameter light-duty cage bearing with the cup part pressed into the hub shell. Maybe I have the wrong piece after all? It`s the next piece behind the sprocket (nice tip, Badmother, but I did in fact remove the clip and sprocket)

Okay, that sounds good to me except that I don`t think I can do more with the grease than squirt a little in there unless I manage to get that cover off. If I push that bearing cage to the side I can get about 1/8 in clearance to dribble it in.

Oil? I know S.A.s use it, but I thought Nexuses were supposed to use only Shimano Nexus grease. In fact, I think S.Brown related that a rash of customers had tried different stuff and they were condemned to saddle sores for all eternity or something. Is that the new recomendation?

About leaving the old grease in there, the original grease is kind of discolored (sliverish, from microscopic wear, I suspect), it isn`t gummy. I would think it`s OK, but I`m still leaning towards Badmother`s idea to flush out the old stuff- just kinda seems right. No, no grittiness or visible sand.

Thank you for the IGH link. If I don`t resolve it here, I`ll go that route. BTW, there is a local shop that services these hubs, but I prefer to do it myself unless it starts looking hopeless.

I`ll see if it show up well enough in a picture to be worth posting.

rodar y rodar

Does this look right? Even though I wouldn`t call it a dust cover, the instructions seem to be telling me that`s what needs to come off.

zephyr

My Surly crosscheck with Nexus8 redlband IGH is just over a year old, and the odometer on the bike shows about 2500 miles. I was thinking this thing is just getting broken in, and performing maintenance on it seems premature. I'm going to wait until about 5K miles to think about any serious lube job. The weather conditions here in southern cal are so mild that this bike doesn't get any severe use. This sounds more like a project I'd do on a rainy January afternoon than in the middle of summer. I'll have to print the instructions and do some homework, and see if there are any funny tools or special lube required.

tatfiend 

Shimano now makea an oiling kit for their gear hubs. It is shown on the current Shimano hub parts lists. Expensive at about $70 for a dipping cup and a liter or so of oil. At least one member of the Yahoo gear hub bikes group has oiled his using synthetic ATF and reports it is doing fine.

here is a link to the oiling PDF.

https://www.shimano.com/publish/conte...ance%20Oil.pdf

rodar y rodar

You might be right, Zephyr. I just got it in my head that I was going to do it now, so that`s what I figure to do (or possibly have done). Besides that, I`m getting the bike tuned and ready to give to some family friends who are in need of reliable short distance transportation. I`ve already handed over commuting and grocery duties to my touring bike. The only thing you might consider to be a special tool is a 14mm cone wrench. About the lube... we`ll see what the experienced folks say. And there`s no need to print the tech pages unless you want to- Shimano and Sheldon Brown both have them on their sites.

rodar y rodar

Whoa! I wonder if that`s intended to do one hub?? I thought the grease was expensive- I think I paid about $15 for it from Harris. From the picture though, it looks like they dipped it with my "dust cover" still in place. ATF, huh? I think I`l look into that Yahoo group after all.

tatfiend 

So far as I can see the oil should be good for multiple dips over a long time. If worried about contamination run the remainder from the dip tank through a coffee filter after dipping the hub.

BTW Liters of both oil change oil and cleaning oil for the Rohloff hub run about the same price each. Of course a liter of each of those is enough for about 30 oil changes on the Rohloff hub. It uses 30cc of each for a full oil change.

Dan Burkhart 

If you remove the carrier unit as shown in step 8, you will have full access to remove the bearing cage and clean and inspect the bearing race.
As far as getting the drive side cone bearing behind the driver plate, I would not worry about that one unless you are doing a complete overhaul. It is so well concealed that contamination should not be an issue, and it will be many years before wear will make it an issue.
If you are determined to go that far, however, I highly recommend you get the tool shown in step 16.
Shimano came up with the oiling proceedure after Sheldon's passing, so he had no opportunity to comment on it.

rodar y rodar

That`s way farther than I have any intentions of going. I`d like to get that next part off so I can get good access to grease it if I end up still going the grease route. Am I actually looking at the right part? If I can`t get it off without fear of bending or damaging anything, I`ll just try the oil plan. In fact, the oil method starting to sound better anyway.

tcs

Perhaps it would help if you refered to the part by number. Or not.

Best,
tcs