Shimano freehub body internals

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nsew
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Joined: 14 Dec 2017, 12:38pm

Re: Shimano freehub body internals

Post by nsew »

I don’t need to try that method because it is clearly half-assed. The objective is to lubricate the freehub mechanism not flood the entire hub, circulating whatever contaminates have found there way in there. But I get it, loosen off the nds and push the ds out and fill with Hillman Imp grease. Sorry, Land Rover.
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Last edited by nsew on 10 Mar 2021, 12:21pm, edited 1 time in total.
Brucey
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Re: Shimano freehub body internals

Post by Brucey »

nsew wrote:I don’t need to try that method because it is clearly half-assed....


wrong twice over. Try again.
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nsew
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Joined: 14 Dec 2017, 12:38pm

Re: Shimano freehub body internals

Post by nsew »

My method, one that lubricates the freehub mechanism with OEM freehub grease and seats the hub bearings in top spec grease that doesn’t migrate to the driveway.
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slowster
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Re: Shimano freehub body internals

Post by slowster »

I have a new rear wheel with a Deore hub which, having run it in for a couple of hundred miles, I am now ready to set up and lubricate. I am keeping my fingers crossed that the freehub has not developed any play which would require removing shims, and that apart from lubrication all I will need do is use Loctite 243 on the right hand cone and locknut.

With regard to lubrication I am going to replace the factory applied Shimano grease with Britpart Landrover swivel housing grease. Brucey, would you still recommend lubricating the freehub with (synthetic) gear oil as per your comments below in this thread, or would you just rely on the SFG in the hub bearings?

Brucey wrote:I think it isn't a bad idea to add a little gear oil to the freewheel mechanism if you have the axle out. Just add the oil where the RH hub bearings go, hold the freehub body in the left hand, and spin the wheel clockwise for a couple of minutes. You can hear when the oil has penetrated the workings by the change in the sound of the pawls. The rate at which the oil then comes out of the freehub body in service is very telling regarding the condition of the freehub body seal (in the LH end of the freehub body). If the RH bearing is then lubed with SFG, the SFG gradually replaces the oil in the freewheel mechanism, and whilst there is enough lube present, the pawls never become (as) noisy again, like they are in a new freehub with bone-dry pawls.
Brucey
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Re: Shimano freehub body internals

Post by Brucey »

I would recommend oil first because unless you do this you can't be certain that the LH seal in the freehub body isn't already running dry and tearing itself to bits; SFG takes a few miles to get into the freehub body and as far as that seal. In the meantime you will see if the seal is in good shape or not by how much oil seeps out.

There is of course no need to dismantle anything (other than the axle itself) unless the freehub body needs reshimming. If you do need to reshim the only parts you need to remove are the dust seal from the freehub body and the cup/lockring from the freehub body. Then you can lift shims using two 'paddle tools' which can be made from pieces of old spoke.

The factory grease is complete rubbish (I have seen countless hubs where it got overwhelmed in just a few weeks and the insides of the hub went rusty) but there is no need to clean it out of the freehub body; there is usually barely enough in there to worry about it. After an oil treatment you won't know there was factory grease there in the first place.

cheers
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hoogerbooger
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Location: In Wales

Re: Shimano freehub body internals

Post by hoogerbooger »

Can I double check Brucie that both the gear oil or SGG can be added by dripping (presumably slowly with the aid of spinning the wheel) to the edge of the cone/recess that the cone & bearings sit?

0_16153878409880.jpg


So no dismantling just a bit of patience and spinning.

And the RH seals will let the oil in.
old fangled
Brucey
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Re: Shimano freehub body internals

Post by Brucey »

not quite, you need to at least pull the axle out on the RHS far enough that the axle seal clears the freehub dustcap. But if you are just adding lube, that is all you need to do.

cheers
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nsew
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Re: Shimano freehub body internals

Post by nsew »

The only way to accurately supply semi fluid grease or oil into the actual freehub mechanism from that side is to fully remove the axle and the dust cap. There simply isn’t enough space as the top edge of the bearing cone sits just below the underside of the dust cap. The only way to achieve it is by overfilling the cavity with SFG or oil and rotating the mechanism to draw it in. That’s messy, liable to draw contaminates into the freehub and you’re stuck with whatever you’ve used to lubricate and protect the main hub bearings on both sides.

After removing the axle (two 15mm hub cone spanners) the plastic dust cap can be gently pushed down with the thumb on one side into the shell. This slightly pops up the opposite side and it can then be pulled out with forefinger and thumb. To re-seat the dust cap, place in the shell and tap down on a flat surface. The cap is properly seated when it sits just below the shell and is able to freely rotate in the threads.

There’s no urgency with that hub (which looks like a 7sp 105) as it’s not built up. Once built the method is to remove the freehub, pop the rear seal and feed the sfg/oil into the mechanism while rotating the mechanism. Park Tool recommend lubricating from both sides following a purge (freehub failure). https://www.parktool.com/blog/repair-he ... ub-service

Why are people so afraid of dismantling, cleaning and lubricating a hub? It’s maintain a bike 101.
Brucey
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Re: Shimano freehub body internals

Post by Brucey »

there is plenty of room for oil to penetrate the freehub mechanism without removing the freehub dustcap. Removing the freehub dustcap is a waste of time unless you intend to reshim the bearings. As I mentioned previously it just takes a bit longer for SFG to penetrate the mechanism, and 'oil first' is the best way. If the oil mixes with a little of the original grease it is no big deal.

If you add oil to the RHS a hub which has standard grease in it and run it for a few hundred miles it will sort itself out such that a second visit will require the addition of SFG only and that will be all that is required for the next year or so.

FWIW in service, any lube which is mobile enough is centrifuged outwards from the hub bearing through the freehub body. As I mentioned previously if there is no seal on the LHS of the freehub body and if the lube is thin/plentiful enough then it can come out and make a bit of a mess, but in so doing it flushes crud out too, so it is not all bad. With SFG and/or a seal on the LHS of the freehub body the rate of loss can be low enough that it doesn't worry most folk; a drop in an ocean of chain lube, more or less.

Some rough calculations suggest that at normal speeds the lube sees a centrifugal effect that is between 1.5G and 2G. During downhill runs at about double normal speed, these forces are x4 so up to ~8G

IIRC CJ has long used a grease gun on his freehubs (via a drilled hole in the hubshell) and ISTR he has mentioned that he hasn't had to take one apart in several decades. When I have done this the hub has ended up overfilled and in subsequent use excess grease usually emerges and needs to be cleaned up. CJ reported no pawl problems even with #2 grease which may indicate that grease takes the path of least resistance, i.e. when the grease gun is used, the grease blows out of the hub end seal before it is pushed through the freehub body wholesale. Many greases, in quantity, will separate (especially if they see 8G from time to time) and I have always supposed it is quite possible that CJ's freehub bodies are in effect lubed with oil which has bled out of the grease.

The same thing won't happen with 'normal' greasing, simply because the quantity of grease is much smaller so there is simply less oil present to bleed out. Nonetheless it is noticeable that the grease in the RHS of conventionally maintained freehubs is often a fair bit drier than the grease in the LHS of the same hub, so some 'bleeding' and consequent loss (via the freehub body) has presumably occurred.

cheers
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nsew
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Joined: 14 Dec 2017, 12:38pm

Re: Shimano freehub body internals

Post by nsew »

Brucey wrote:there is plenty of room for oil to penetrate the freehub mechanism without removing the freehub dustcap. Removing the freehub dustcap is a waste of time unless you intend to reshim the bearings. As I mentioned previously it just takes a bit longer for SFG to penetrate the mechanism, and 'oil first' is the best way. If the oil mixes with a little of the original grease it is no big deal.

If you add oil to the RHS a hub which has standard grease in it and run it for a few hundred miles it will sort itself out such that a second visit will require the addition of SFG only and that will be all that is required for the next year or so.

FWIW in service, any lube which is mobile enough is centrifuged outwards from the hub bearing through the freehub body. As I mentioned previously if there is no seal on the LHS of the freehub body and if the lube is thin/plentiful enough then it can come out and make a bit of a mess, but in so doing it flushes crud out too, so it is not all bad. With SFG and/or a seal on the LHS of the freehub body the rate of loss can be low enough that it doesn't worry most folk; a drop in an ocean of chain lube, more or less.

Some rough calculations suggest that at normal speeds the lube sees a centrifugal effect that is between 1.5G and 2G. During downhill runs at about double normal speed, these forces are x4 so up to ~8G

IIRC CJ has long used a grease gun on his freehubs (via a drilled hole in the hubshell) and ISTR he has mentioned that he hasn't had to take one apart in several decades. When I have done this the hub has ended up overfilled and in subsequent use excess grease usually emerges and needs to be cleaned up. CJ reported no pawl problems even with #2 grease which may indicate that grease takes the path of least resistance, i.e. when the grease gun is used, the grease blows out of the hub end seal before it is pushed through the freehub body wholesale. Many greases, in quantity, will separate (especially if they see 8G from time to time) and I have always supposed it is quite possible that CJ's freehub bodies are in effect lubed with oil which has bled out of the grease.

The same thing won't happen with 'normal' greasing, simply because the quantity of grease is much smaller so there is simply less oil present to bleed out. Nonetheless it is noticeable that the grease in the RHS of conventionally maintained freehubs is often a fair bit drier than the grease in the LHS of the same hub, so some 'bleeding' and consequent loss (via the freehub body) has presumably occurred.

cheers


There isn’t “plenty of room”, in fact there’s no room. Your method acknowledges there’s no room because in order to lubricate the mechanism the hub has to be flooded with oil to lubricate a separate mechanism. That much is bleeding obvious.
nsew
Posts: 1006
Joined: 14 Dec 2017, 12:38pm

Re: Shimano freehub body internals

Post by nsew »

How to remove clean grease install a freehub body. I find his methods a bit agricultural but they can be refined.

https://youtu.be/f19BGYc5ysA
bgnukem
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Re: Shimano freehub body internals

Post by bgnukem »

For the time it takes to remove it (seconds) I always take the freehub body off the hub shell and introduce the grease through the rear seal. It means I can clean up the seal and remove any excess grease from the rear of the freehub body and the hub shell before it starts running along the spokes towards the rim.

Everyone's got their preferred method though I guess.

Might try some SFG in future as I can agree with Brucey that NLGI No. 2 grease is a bit thick for the pawls and does cause some slippage initially after re-greasing, until the grease is 'worked' a bit inside the freehub body and thins out a bit.
nsew
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Joined: 14 Dec 2017, 12:38pm

Re: Shimano freehub body internals

Post by nsew »

Yes that whatever it was grease should be purged as it’s not formulated for a freehub. It will gunk under and around the pawls and springs in times of inactivity or when the temps drop/fluctuate. If spending £10 on a tub of freehub grease that lasts 15 years and services two bikes is too much then that person may be beyond help. Same applies for a top quality bearing grease that remains in situ longer than all others and that costs £5 and lasts 8 years liberally used across two bikes. 50p a year is too much for some people and they pat themselves on the back for spending the equivalent amount on 1kilo of stuff that they won’t use 1/100th of that was formulated for a tractor.
Brucey
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Re: Shimano freehub body internals

Post by Brucey »

nsew wrote:

There isn’t “plenty of room”, in fact there’s no room. Your method acknowledges there’s no room because in order to lubricate the mechanism the hub has to be flooded with oil to lubricate a separate mechanism. That much is bleeding obvious.


wrong again.

Look: I have been lubricating freehubs this kind of way for over thirty years. You are busy telling me I am wrong when you have not even tried it.... :roll:
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nsew
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Joined: 14 Dec 2017, 12:38pm

Re: Shimano freehub body internals

Post by nsew »

Brucey wrote:
nsew wrote:

There isn’t “plenty of room”, in fact there’s no room. Your method acknowledges there’s no room because in order to lubricate the mechanism the hub has to be flooded with oil to lubricate a separate mechanism. That much is bleeding obvious.


wrong again.

Look: I have been lubricating freehubs this kind of way for over thirty years. You are busy telling me I am wrong when you have not even tried it.... :roll:


I won’t be joining yourself and your followers at the hidden retreat to partake of the tractor grease.
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