Is it possible to rebuild an 8 speed freewheel

[Slimtim]

I have a Sachs Maillard LY91 8 speed block. I don't have the tool to remove it from the wheel (but am looking for one if you have one!) but it feels like the bearings have become worn as there is some play. The block still spins but is noisy and 'wobbly'.

Is it possible to rebuild such a unit and if so how difficult? Would I need lots of special fit tools?

I would like to rebuild as it would be interesting and i like the ratios.

If it's not possible, does anyone have a suitable replacement (ideal ratio 12 straight up but open to offers)?

[thirdcrank]

SB has advice on how to do it (after he first points out it's a waste of time.)

http://www.sheldonbrown.com/freewheels.html

scroll down

[Brucey]

this is a fair amount of work for not much gain in most people's view. Having said this, all such freewheels are designed to be maintained and adjusted if necessary.

The looseness is wear in the bearings; the roughness means the bearing surfaces are no longer smooth. You can get rid of the play but the bearings will always be a bit rough if they are rough now.

You need a hammer, punch, (and maybe bench vice).

With the freewheel on the wheel still, use the hammer and punch to loosen the lockring (it is on a left hand thread NB) and remove one or more shims from under the lockring. Experiment with fewer shims until the bearing has just a tiny bit of play in it when the lockring is fully tight.

Obviously one false move during this process and balls will fall all over the place.... one tip is that it is often a bad idea to remove the base shim, since this can let balls fall into the pawl slots (very bad).

If you can't re-shim it to make it work, or you find that the pawls are bad, or w.h.y. then maybe you will have to bin it. If your new freewheel will have a different fitting and/or you don't want to buy the correct tool to remove the old one, once disassembled you can simply hold the centre of the old one in the bench vice and unscrew it. This might wreck the centre but this is of no consequence if the freewheel is scrap anyway.

cheers

[Mick F]

I'm not familiar with your FW block, but I would say you could refurb it.

Sheldon Brown was someone who is/was held in great esteem, but I must say I disagree with him about this subject - among others!

Firstly, you'll need to take off the cogs. You will need a pair of chainwhips. Then, you'll need a freewheel block remover that fits properly. A big spanner isn't usually enough, so the tool should be mounted in a vice and the wheel turned to undo the unit off the hub.

Look at the link above, and read thoroughly. Basically, a ring will need to be unscrewed (LH thread) and usually there are thin shims under the ring. There are balls - loads of them - in two races. No doubt they are worn, especially the inboard ones. You need to buy new balls.

When you reassemble, gently tighten the outer ring with all the shims in place. If there's some play, remove a shim or two. You may find the shims are of different thickness. Eventually, you should end up with a freewheel that is ok.

Possibly, you may have a double ring system. ie a lockring and a cone system. This system doesn't have shims and the adjustment is done like you would do a cup and cone wheel hub.

Make sure it's all very clean and use a decent grease. Take care not to loose the ratchet pawls and springs. Reassembly is a delicate operation and some cotton thread may be needed to hold in the ratchet pawls as you put it all together. Pull out the cotton as the inner unit goes in.

I used to do this operation every year, and by doing it, I kept my freewheels running sweetly.

[Brucey]

Mick is quite right; I was forgetting it is an 8-speed straight up block; most likely the end sprockets will have to be unscrewed using chain whips to allow good access to the lockring. This could be rather difficult, as the sprockets are sometimes extraordinarily tight.

IIRC all Maillard freewheels have a lockring/shim system BTW, not a cone/locknut arrangement.

You may find that you can fit the 8speed cogs to a 7speed maillard freewheel body BTW; worth checking this as 7speed freewheels are easier to come by.

cheers

[Slimtim]

Thank you all for the swift response. I will have another look at the freewheel this evening and borrow my neighbour's chainwhip.

Should the lockring undo anti-clockwise? I am assuming so.

[Mick F]

No, the lockring is a LH thread.
Turn it clockwise to undo, just crack it open so you can turn it with your fingers, but make sure you do this before taking it off the hub.

When it's off, you can unscrew completely. Do it over a dish/bowl to catch the bits.

[gaz]

.

[thirdcrank]

gaz

I think that shows how the multiple speed freewheel was a sort of evolutionary dead end. The original freewheel was a single speed so it was fastened on in pretty much the same as a cog, but without the lock ring. As the number of sprockets increased, so did the daft ways of hanging them on a freewheel body.

At some stage, somebody thought it through pretty much from scratch and came up with the freehub arrangement. I suspect that if freewheels had been multiple from the start, then the screw-on system would never have been used.

[gaz]

.

[Mick F]

I always used to worry about the alu threads on the hub being stripped. Those FW blocks screwed on damned tight, what they must've been like on a tandem, goodness only knows.

I bent my two-dog tool unscrewing one once, and damaged the FW unit, I had to dress it up with a file eventually but I ended up buying another - plus a new tool. Later, I went to a four-dog system, much better.

The trick was always to screw the wheel-nut on to hold the tool in place, but it was still a devil to undo. I used to worry about overstraining the wheel as well!

[Brucey]

and the freehub was invented by......

Sun Tour, some say.....

Back in the 60's.

Thats if you don't count the SA hub gear as being a kind of freehub, that is....

cheers

[Mick F]

PS.
I used Suntour Ultra 6 for years, then went to Ultra 7.

The 6 and 7 FW units were identical. The 7cog screwed onto a 6cog - a special 6cog at that, it had threads on the outside. Minimum teeth of the 7cog was 13t.

I still have the 14/13 screwed together - for the life of me I cannot unscrew them apart.

[BigG]

Don't forget that the only time a freewheel mechanism operate is when you are freewheeling. All of the rest of the time, all its parts including the bearing are stationary. A little roughness while freewheeling is not much of a problem. Unlike with a freehub, the wheel bearings are not involved.

[Mick F]

Couldn't resist this:
Unlike a SHIMANO freehub, the wheel bearings are not involved.

Unless the FW unit is free and smooth running, you will get poor shifting and the chain smacking the chainstay. Rain and muck gets in through the inboard bearings. I used to lie the bike down on its right and drizzle oil into the bearings whilst turning the wheel backwards. Messy job!

Eventually, I bought a sealed unit - Mailard I think. It had different splines to the Suntour Ultra. I sold the whole unit a few years ago on these very pages.