hukapits

Hi All,

Does anyone know or have information/link on how to dismantle shimano's freehub body ?
I'd really like to know

Regards,
Huka

FBinNY 

If you're talking about removing the freehub body from the hub, it's held on with a hex nut accessible when the axle is removed. This is covered in Shimano's tech docs, and in tutorials easily found on the net.

As for taking the freehub module apart, to my knowledge, nobody bothers. They either replace them as needed, or pull them back from death with a long soak in a can of solvent, flush out dirt/rust with more solvent, shake them dry, and let some heavy oil soak in. It's sort of the same way we used to keep out freewheels going. Both with freewheels or freehub bodies, there's little or nothing to be gained by actually taking them apart.

Kimmo 

I bother.

Actually, many of them have a little free play, so often a slight improvement in shifting can be realised by removing a shim.

fietsbob

I'll just Watch :

dabac

https://happymtb.org/forum/read.php/1/144572
It's in Swedish, I'm afraid, so you'll probably have to rely heavily on the pictures.

But the key points are that the Drive side(DS) wheel bearing cup that gets exposed after removing the DS dust shield is threaded left, and also compressed by the hollow bolt holding the body to the hub.
Loosen (don't remove) the hollow bolt by 1/4 of a turn or so,
then break free the bearing cup,
then undo the hollow bolt the rest of the way.
Pluck body from hub, put on terry cloth(those tiny balls go everywhere!) and remove the bearing cup.

You should be able to take it from there. If not - ask.

While readily doable, there are some pointers. The bearing cup can be real tight(and it's a leftie, remember) so you need to pay attention to what you use as a tool.
I've never had any luck with general construction steel - too soft. I had a bit of luck using a file. But it eventually met its match and snapped into really nasty shards one day.
My current tool of choice is a much thicker file, where I actually had to grind it down a little to fit into the notches of the bearing cup.
The guy in the pic is using a ground down cone wrench, which is obviously working for him.

Apart from that, the biggest thing is that there seems to be a really tiny window between running rough enough to notice, and worn beyond saving. I've had good success in salvaging freehubs that's gone sticky in cold, but not much with those that's begun to run ragged. Bearing surfaces and bearing balls are small, they trash easily when contaminated.

hukapits

I think FB got a point but Kimmo you really get me going. Do you have an info regarding this overhauling shimano freehhub body kimmo ? kind of DIY step by step

hukapits

thx Dabac

Kimmo 

Did you click the link in my post above? I made it a link in my tag as well.

That's pretty much all you need to know.

Actually, the hollow bolt doesn't compress the cup; the cup goes around the central bit of the cassette body, but not over it. So, I say crack the cup loose then remove the hollow bolt in one go before continuing with the cup.

dprayvd

Is this what OP's thinking?

Everyone else, enjoy.

And the race/cup tool for me is diy flatbar, cuz I had to do it on the day....

edit: of course, this is to reiterate Kimmo's goods.

hukapits

I found this tool in my LBS, it's said for Suntour 2 Notch freewheel. Does it also work shimano freewheel ?

dabac

Freewheels and freehubs are two entirely different animals. All Shimano freewheels I've come across have needed a splined tool to be removed from the hub, and carefully applied violence to be opened.
Don't know if a freewheel tool meant for another purpose entirely would just happen to be useful for cracking open a shimano freehub.
IME, the world of mechanics usually isn't that benign. But, stranger things have happened.

cs1

According to the Guru:

cs1

SunTour used the 2 prong version and Shimano the 4. But that's for a freewheel not cassette hub.

MichaelW

There is a useful discussion of Shimano Freehub servicing over at the Cyclists Touring Club, inc one guy who built a special tool, an improvement over the TL FH 40

ksisler

OP Huck; Simple answer is; not even close. Recommend going to the Park Tools site and look through the ones they sell. Should be enough data there on the "this tool fits that brand/line/models" for you to figure them out. Most indicate what other regular tool you need to turn it with, such as the one from a splined Shimano cassette requires either a 3/8" socket handle or breaker bar or a 1" wrench. Once you have the Park item number identified, compare the price there with what you can get it for off amazon and roll your dice. If you need to pick up an affortable set of sockets or a breaker bar handle, you can find a ton of them on Amazon or at a Harbor Frieght store if you have one nearby. Might want to check to ensure you have a chain whip also...you will need it to hold the cogs while you wrench on with the remover tool. Smart if you were to get 2 chain whips as you will need 2 for some cassettes or freewheels. They are about $10-14 each on Amazon...

Hope that helps
/K

400trix

Morningstar Tools has a device called a Freehub Buddy that allows you to change the lubrication inside the (Shimano) freehub without completely dismantling it.

hukapits

Forgive me if I made it unclear since what I meant was whether this tool (i pic above) could be a substitute for Shimano TL-FH-40 ?

Jeff Wills

No it does not.

If you want to disassemble a Shimano freehub body, a friend of mine makes a tool to do this: https://efficientvelo.com/tools/wheel-hub.html#cass
Note that the tool costs as much or more than an entire replacement freehub body. I would only rebuild one if there was prize money involved.

dabac

I have no idea if it would fit or not, but why not try an improvised tool first? Yours may come apart by nothing more than a piece of flat metal stock. If you have a bench grinder, you could take a suitably sized socket and grind it down until you're left with two pegs. Or some other option. Plenty of things that'll fit into two notches.

davidad

If you are trying to make one, the diameter of the shimano tool is 27.5mm. I use mine to add a heavier pawl spring so that I can pump grease through the freehub body with the Morningstar Freehub Buddy. https://morningstartools.com/Pages/FreehubBuddy.aspx

DannoXYZ 

Also note that the bearing-preload is not adjustable. If you find that after disassembly and putting it back together there's more or less play than before, there's a stack of thin shims that's used for adjusting the bearing-clearance. Add or remove as necessary.

Ranger63

So; soaking in a solvent ,shaking out and then soaking in something like 30wt. will do the trick without damaging the freehubs innards?
I've got a 8-9 NOS tiagra/mavic cxp wheelset and the freehub is dragging -probvably from the fact that the lube in the body is...old.
I was simply going to pick up a new 8-9-10 freehub from the LBS but if this will work it can save me some bucks.

HillRider

Usually it will free up a sticky or dragging freehub quite nicely. It certainly costs almost nothing to try. If it works, you are home (nearly) free and if it doesn't, little is lost.

dddd

Once I've pulled the axle out, I hold the wheel upright, with the hub horizontal (as it is while riding).

Then, I add a dozen drops of motor oil into the open end of the freehub body, just behind the dust shield (which I never remove).

After 30 seconds or so, I tilt the wheel/hub slowly to the left, so that the oil slowly creeps in behind the bearing cup in the freehub body.

Unless the hub has previously been over-greased, the oil runs right in, and there's no dirt there for the oil to wash into the bearings.

Then I spin the body, and turn the wheel to different positions to distribute the oil.

It helps to heat up the freehub body with a hair drier before adding the oil, it will penetrate faster, but is usually not necessary unless the temperature is low or the oil is a thicker grade.

I also have an oil squeeze bottle with oil that has been diluted with solvent, and this stuff penetrates fast without the benefit of any warming.

Count me in as one who hasn't felt the need to ever take a Shimano freehub apart.

Ranger63

Gave it a go over the weekend.
Sence I had several 7spd freehubs with the same bearing seal at the hub end, I flushed the hub in a jar of lighter fluid, shook off the excess, removed the seal and placed the hub -bearings side down-on a clean cloth to drain.
turning the hub bearings side up I soaked it in some warm 40wt. for about 10 minutes, removed, wiped off,replaced seal and installed the hub and an old cassette onto a hub and spun the cassette.
HUGE difference,