Rear hub making a grinding noise

It's a Shimano XT of some kind. Had problems with it for ages, bearings magically going from too tight to too loose as they wish. So today I took it all apart, cleaned and regreased it all as per the guide on MountainBikeRides.co.uk. Put it all back together, again as per that website. The only thing I didn't do was take off the freehub as I couldn't see how.

Now when the wheel spins it sounds like this and still doesn't spin freely – https://www.yousendit.com/download/K0JSM25DTk1wM2swTVE9PQ

Why would it be making this sound? I've put it back together in the right order as far as I'm aware.

To be honest I'm tempted to just bin it and get a new wheel with a decent sealed bearing hub. I've never liked cup and cone and always seemed to have problems with it on my old bmxes. Anyone got a spare one I can have?

ive had the same problem, i think its the freehub thats gone ,you undo it with a big allen key, im fed up with cup and cone so just bought a superstar rear hub, cheap as chips, uses sealed bearings so easy to service, very similar to hope inside (although obviously not the same quality). Just built it up and it's excellent ,definately reccomend them

i paid 40 instead of 30 for the switch for the 100grams lighter and abilty to switch axle types(the latter i will never use)

wheel building is also alot easier than i thought it would be, the sheldon brown guide is excellent, you can use your old spokes too

Yeah I've built up a couple of bmx wheels before, they're still going strong now apparently!

Will have a look at superstar. I've used some of their other stuff and its been great.

Sorted! It wasn't anything (really) to do with the hub. I think when putting it back together its somehow shifted slightly toward the disc side. As a result the disc is a bit closer to the mount (which is a close fit anyway), and was rubbing on the ends of the bolts which aren't completely flush. 4 spacers later and it's no longer rubbing.

However I think the freehub is still **** as it no longer clicks – just makes an unsatisfying whirring sound!

I need to replace the axle/cones at some point as well, does anyone know where to get one to fit the FH-M756?

LBS – call madison?

Part numbers here:

http://techdocs.shimano.com/media/techdocs/content/cycle/EV/bikecomponents/FH/EV-FH-M756-2099A_v1_m56577569830608935.pdf

CRC do M755's for £25 for the complete hub – from what I could see the parts are interchangeable with 756's so you'd get a replacement freehub. axle and bearing set for £25. If you think not they do 36 hole 756 hubs for a bit more and you can use those as donors.

Good thinking WW 🙂

Madison stock the axle 🙂 A new axle + freehub body cost more than the RRP of the hub though, is it worth it?!

wssaswas are you sure they're interchangeable? If so that's a great idea 🙂

You won't need a new axle. I'd get the hub, a spare freehub is worth having. Check it's compatible though.

I've got a 755 and a 756 here and had both apart (at the same time) I really couldn;t see any difference in the freehub fitting/axles or anything. the only difference seems to be some extra machining on the flange where the spoke holes is for the 756 hub.

clearly I don't want to cost the op £25 but I'd spend £25 of mine based on what I see. Maybe Mark from Madison will pop along soon and confirm…

^The axle and cones are in pretty bad shape tbh. Axle threads are worn on the ends as are the cones/lock nuts (looks like they've been held with pliers rather than proper cone wrenches). The non drive side cone at least needs replacing as its got a rough patch which seems to be making the wheel spin badly.

Just comparing the two technical documents, so far its looking like all the part numbers are the same so it should all work?

As long as you can get the cones on and off then the axle threads are fine.

If the freehub body is OK then I'd just get a new cone (and bearings?)

The freehub is a different part no on the 755 so maybe it won't work.

Is it definitely the freehub body that's broken if when freewheeling it no longer clicks like it used to?

You will now whether its broken when you ride it. My Shimano freehubs are near-silent.

I think you'll be OK 755-756 freehub, newer ones have an entirely different fitting method which is what concerned me.

yes, the freehubs look the same – I checked them against each other when I had the hubs apart. As I say all the parts look identical – it's just the hub bodies that look different.

Oh I can still ride, it just doesn't sound or feel right/like it used to! Probably just gonna ride it til it breaks for now haha, so long as it won't cause a painful crash if/when it does break.

Cheers wwaswas, when it goes then the 755 should be an ok replacement then..