Servicing M900 rear hub

[frye]

Hey everyone,

I'm currently servicing a M900 rear hub (still need to find time to put up a build thread...) and have a few questions.

- I'm missing a seal ring on the right hand cone : how bad is it ? Are these kind of seals still sold somewhere on the internet, or should I rather try to salvage a ring from another hub I have yet to find ?

- The threads on both ends of the axle are pretty worn out (see pictures) and I'd like to freshen them up but I'm not sure about the thread pitch : is it M10x1mm or some Italian thread pitch in tpi ?

More generally, do you have any website where I can find high quality replacement parts for these kind of hubs ? Bearing balls are easy to find but seal rings or cones or freehubs not so much :/

Thanks for your help !

frye

 

[FluffyChicken]

Don't worry about the end threads, they're better like that, it the dropout part. But find a lightweight standard axle. Even Titanium you want...

Which seals etc ?

 

[FluffyChicken]

If it is #6 on the drive side, then it a fairly specific seal for the hub, or at least was at the time, as it was part of the cone, not many had that setup

The comes are quite specific too as they had the longer inner part and that seal, you'd need to make one up iirc, or find it on another hub, maybe the Ultegra/DuraAce* end road hub at that time, see what looks right.

But if the cones are shot, there is a good chance the ones in the hub body and freehub body are too, that's a whole different set of pain.


*I forget, there have been posts on here but nothing came of them other than a makeshift setup iirc, things may have changed in 15 years.

 

[Tootyred]

Agree totally with fluffy...if the cone is shot to bits, it very very likely the race inside the hub is too. Sadly that can't be replaced.

Its the risk of second hand or unserviced hubs.

 

[frye]

If it is #6 on the drive side, then it a fairly specific seal for the hub, or at least was at the time, as it was part of the cone, not many had that setup

The comes are quite specific too as they had the longer inner part and that seal, you'd need to make one up iirc, or find it on another hub, maybe the Ultegra/DuraAce* end road hub at that time, see what looks right.

But if the cones are shot, there is a good chance the ones in the hub body and freehub body are too, that's a whole different set of pain.


*I forget, there have been posts on here but nothing came of them other than a makeshift setup iirc, things may have changed in 15 years.

Yes it is #6 ((
The cones seems to be pretty clean imo, I'll take more pictures tonight !

 

[frye]

Don't worry about the end threads, they're better like that, it the dropout part. But find a lightweight standard axle. Even Titanium you want...

Which seals etc ?

It's the dropout part but I think I'll have trouble putting back the left hand cone and washers because of worn out end thread...

 

[hamster]

I wouldn't worry - backing off the cone and removing it will clean up the thread.

 

[Dr Dremel]

It's the dropout part but I think I'll have trouble putting back the left hand cone and washers because of worn out end thread...

If the cone is ok I wouldn´t bother removing it. Aditionally: Replacement cones are pretty bad quality in my experience.

Regarding seals: I think the M900 has the same seals as XT or Deore from this period.

 

[bikeworkshop]

As a rule, the cones wear out twice as fast as the (technically non-replaceable) cups
(and the drive side wears out 2x the nds),
so 1st time, new cones
(replacing pitted numbers)
makes a hub feel a lot nicer,
but not perfect,
because there's still some wear on the cup.

Wheels manu. make vintage shape shimano cones, but m900 might be too long ago.

The old boys used to skim their cones on a lathe after a million miles to get another million miles out of them you'd probably need another spacer to pack out the axle.

Thel seals keep the crap out and the grease in. You might be able to fabricate something or modify a similar seal - it's filling a gap.
extra servicing will help.

I've seen those same old boys use
pipe-cleaner for hub seals, but tbh pipe cleaners are probably as rare as fh-m900 parts these days, and you might need a license to buy them

As for the axle end, you could extract everything off the other end and then leave that side assembled.

 

[frye]

Thank you all for the tips Very much appreciated ! It seems XT hubs from the same era (737) have the same seals, i'll try to get a cheap one somewhere.
As for the threads, I will keep the right hand cone on the axle and put back the left one without bothering too much about the threads.

Will update with a few pictures of the cups and cones for experts' eyes to check if they are still good to go