took my rear wheel out the other day and the cassete block has a little movement up and down (as in,when its in the bike it would be up and down)
the hubs are bottom of the range deore and cassete is a hg40 8 sp.
the cassete is in need of replacement as its worn but as im no expert in these things can any one guess if its just the inner part of the cassete or the fre hub thingy bit? if its the free hub would that be easily repairable
ps its not the cones, i know that much, it is the cassette assy area.
cheers

is it a shimano hub?

sounds to me like the freehub has come loose.
cant see how the sprockets could move on the freehub body.
it involves stripping the wheel, taking out the axel and bearings, and tightening the fitting that holds the freehub unit onto the hub.

down the hole where the axel comes from (if you see what i mean) you should see its actually hexagonal inside.
14mm i think?

did you know you can add allen keys together?
stick a 10mm key down, and a 4mm key next to it, and it will be fine to tighten up the bolt.

this is the bit to tighten, holds the freehub onto the hubshell

ok. it is only a tiny bit of movement. i was guessing it was wear someplace??
bottom of the range shimano deore hubs.
if i get the tool to remove the star shaped lock nut jobbie that hold the cassete on, doe the cassete come off easily or will it need to be pulled off somehow (ie with another tool?)

I have had this before on an XT hub. I whipped off the cassette with a chainwhip and and cassette tool, removed the cones and axel, and my freehub body was losse, I tightened it up with a 10mm allen put it back together. Sorted. A little tip when removing the axel, its worth getting the vernier and measuring how far the thread is proud of the axel – saved me a lot of fannying about then re-building the hub.

it should just slide off, but be aware, that youll need to hold the casette still to be able to get the lockring off.

you could buy a chainwhip like a normal person, or you could shred your hands by fashioning a chainwhip from an old chain, a piece of towel and some gardening gloves like me.
i would reccomend the chain whip.

once the casettes off, see if you can waggle the free hub body

see how theres only 2 sets of bearings, if the union in the middle, between the hub shell, and the freehub, isnt tight, there can be what isessentially a "bending" in between the two.
if that makes any sense.

Could just be worn splines on the cassette. You won't know without removing it. You need a chain whip to hold the cassette while you undo the lock nut. Once the lock nut is off the cassette will fall off.
Check parktool.com for detailed info.

(edit: looks like we were all typing at the same time!)

ok i will investigate this in more detail after work and post later.
cheers all.