Long story short, I think my freehub might be knackered, or at the very least need packing with some more grease (http://www.singletrackworld.com/forum/topic/rear-wheel-doesnt-sound-smooth-when-it-spins-bit-noisy-whats-the-problem?replies=13#post-1299282).

Apparently I will need a special tool to grease the freehub – has anyone got a link to such a device or instructions how to do this? Thanks all!

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

(clicky)

Yup. Good clean first.

you can sort of do it without a freehub buddy. remove the freehub from the hub and lift out the rubber seal on the back, then dribble in a load of oil, engine ol works well, with the hub stood up with the missing seal to the top spin the freehub. Pretty quickly the oil will work through and come out the bottom looking mucky. add more oil, spin some more until bored or oil getting cleaner as it emerges, then pack some grease in the same place and spin, pack more grease and spin, replace seal.
You won't get loads of grease in but the thickish oil stays in fairly well and lubes the freehub for ages anyway.

My XT freehub started making a louder noise and then got a bit stiff. I took it off the hub and poked out the seal. Underneath were the brown bearings (I think I should have done this sooner).
I filled an aerosol cap with oil and immersed the freehub and spun it round until it was full of oil. Then took it out and spun it until most of the dirty oil had drained out. then repeated this process a few times until the oil was coming out clean, popped the seal back in and put it back on the bike. It now runs smoothly. I don't think grease would be a good idea because it could make the ratchet pawls move more slowly and not engage reliably. The freehub soup in the clicky would be better than oil or better still a new freehub.

Ok… lets just assume that I am willing to have a go at bodging before replacing… what kind/weight of oil would be best? 3 in 1? 😳

when i used shimano i used what ever i had, chain oil, gt85, anything fairly thin that won't make the mechanism sticky

Has anyone got a buddy or soup from that site? I only ask, I was thinking of ordering, but it says it's not been updated since 2004!

They are not really user-serviceable. I have a friend who owns a garage and he's solvent-cleaned then re-lubed one for me. However, its not long before the pawls start to mis-engage which will cause a nasty knee/stem interface.

I used to buy a complete rear hub from CRC for less than the cost of a freehub then change all the bits over (axle, bearings etc) and I'd have a free skewer and paperweight!

Looks like a lot of hassle
http://www.5min.com/Video/How-to-Overhaul-a-Shimano-Hub-and-Free-hub-66770627

I had a go at this after advice from the forum a few weeks ago, muck, crap, oil and grease everywhere – get a new one and save the hassle!