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Is there any way to do a home-made sealing on my freewheel?

Is there any material recommended to do it?

Anyone can find some previous try documented?

Will I fail miserably if I try to source a sealed component with the same diameter and reuse the seal? What exactly is the seal?

Just a little of background: After fixing my freewheel, it does not spin with grease. So I used chain lube. It works, but for a little more than 2 weeks only.

UPDATE 1: more info.

The focus of the question is: wheel hubs and other parts with MUCH more stress are sealed alright. Why freewheels can't?

It's a 5 speed Shimano freewheel. I was considering replacing it with a 6 speed since my shifter and RD works fine with it. but looking at the options, i refuse to give money to freewheel manufacturers! It's all crappy. even the high end models. Also, the gears are like new yet. bearings has no imperfections. it's just a matter of lubing.

So, I did open and serviced that freewheel (didn't take pics as I did it overnight alone and was aiming for speed so i could get some sleep).

At first I greased the hell out of it and closed. It spinned as bad as when it was dry and dirty (it has 12yr)

Then I reopened, cleaned it all again with 90% oil. Applied just enough grease to barely hold the bearings in place for assembly (an invisible film) and right after closing it up again dropped a bunch of 20w-50 engine oil and a bunch of chain-L oil (the snake oil of bike chain lube.)

It's spinning like new. but after 2-3 weeks, i often get one or another small chain drag when backspinning the pedal very slowly. No issue at all, but a sign that it's not perfectly lubed again. and will only get worse.

Tip

If the gears are not worn but the freewheel does not spin:

  1. remove wheel
  2. let if lay down with the freewheel cogs on top
  3. use a spanner tool to remove the cap on the freewheel
  4. drop oil in there
  5. close it

As you can see, it's pretty easy to oil the freewheel. and all bike shops I ask about sealed freewheel and freewheel maintenance say that, 1. there's no sealed model. 2. you HAVE to do this oiling twice a year. 3. There are no consensus to which kind of oil.

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It's not quite clear what you want to do. Where do you want the seal to go? Generally the places that could be sealed on a freewheel are pretty well protected anyway, so they shouldn't need sealing. –  Daniel R Hicks Aug 9 '11 at 2:43
    
Is this a multispeed freewheel? Singlespeed? BMX? –  zenbike Aug 9 '11 at 4:23
    
@daniel i want to prevent oil from going out. –  gcb Aug 9 '11 at 18:16
    
@zenbike i put more info there. It's a BMX 5speed freewheel shimano MF-Z012. Btw, i'm still waiting for the slick honey oil you suggest on another question when i was still trying to remove said freewheel :) –  gcb Aug 9 '11 at 18:17
    
If you use the Slick honey, it will last longer, but quite honestly, if you have 12 years use on the freewheel, as soon as the grease thins out even a little, then the pits and chips on the bearings and races will cause immediate issues. That sounds more like the issue you're having, and it won't be fixed without simple replacement if that's the case. –  zenbike Aug 9 '11 at 19:31
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5 Answers

As far as the increase in drag after a few weeks, I reckon the Chain-L oil is to blame for that. As far as oils go, it's not all that heavy, and over a few weeks can migrate out from where it needs to be inside the freewheel.

One of my favorite things to do with an old free wheel is to soak it in degreaser/solvent/parts washer overnight. Then, use rags and compressed air (or opening it up, if you like tiny bearings in abundance) and clean out the degreaser. Once the freewheel is bone dry, slowly dribble in some Phil's Tenacious Oil while spinning it. Ill often set the freewheel onto a freewheel tool in a vice and spin it with one hand while holding the Phil's bottle in the other.

The dry freewheel will ratchet very loudly, but you'll hear it quiet down as the very thick oil begins to penetrate. Once you start to see some oil come out the other side you know you're done.

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everyone recommends this oil, even on the older answers right here... but for $15-20 each 4oz bottle i'm considering stocking freewheels. but the topic here is for a wacky try at sealing the freewheels :) –  gcb Oct 18 '11 at 9:05
    
@gcb: if you have a $15 freewheel, it's probably worth replacing. I ride a $100-ish White Industries freewheel that's sealed and easy to take apart to re-lube if desired. And once it's apart, you only need a tiny amount of oil to keep everything going. –  jrockway Oct 18 '11 at 15:43
    
@jrockway i looked into white industries but they only make one speed stuff that does not help for long distances and/or mountain. And that's a very valid point, why there's no $50 sealed freewheel? only $12 disposable ones. My sealed hubs on that bike are 13yr old and run great. –  gcb Oct 20 '11 at 22:05
    
@gcb: my apologies for not noticing that you wanted a multi-speed freewheel. i guess most people with $50 to spend upgraded to a freehub (though those aren't sealed either, oddly enough) –  jrockway Oct 27 '11 at 20:51
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I understand what you're trying to do but why is it important? You're concerned about the amount of drag you get from the freewheel when you're coasting, this can't be very much.

If the drag is so bad that when you push the bike by hand the pedals turn then I'd say something is very wrong.

But if you're just feeling some small amount of drag that's OK. Why? because when you're coasting, you probably don't care if you have little bit of drag in the hub and you're probably going downhill anyway. The freewheel does its job when the pawls inside are locked with the hub, when the pawls are disengaged and you're coasting, you just have some slight friction from metal-oil-metal with no significant loading.

This is why Sheldon Brown says it is not worth it to service the freewheel.

Just buy a new or a NOS (new old stock) freewheel. Loosescrews is a good source for basic stuff. You might also be able to find a high-quality NOS Regina from the 70's or 80's (that might be worth servicing).

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Amount of drag, even if minimal, drags the chain on the frame. also i have a 5sp 13-30 that i'm very found of :) –  gcb Aug 22 '11 at 3:13
    
Even if i buy a new one, the manufacturer recomends i lube it every 6months or less (BMX forums everyone lube the nonsealed free[wheels/hubs] everytime they lube the chain) so i'm trying to think on a long term solution. i don't want to replace a very good working piece just because it's missing oil every year. –  gcb Aug 22 '11 at 3:15
    
Just read what Sheldon Brown says. BMX riders might be more interested drag whilst coasting for very specific reasons that would mean nothing to a road rider. Freewheel lubrication is simply never a problem under normal circumstances. If in doubt, squirt some oil in there. If you're concerned about the "long term", note that the cogs will wear out MUCH SOONER the freewheel pawl mechanism. –  Angelo Aug 22 '11 at 3:40
    
the pawls are fine even on my old one. the cogs too. The issue is the lack of 'freewheeling' when coasting or backpedaling. If there's not much momentum it will sometimes slightly drag the chain forward just enough to keep hiting my frame. I do add oil every now and then (3-4wk). I tried adding grease, but it generates even more drag. –  gcb Aug 22 '11 at 5:35
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Multi-speed freewheels do not work if packed with grease. To assemble it so that it works trouble free you will need a space cleaner than an integrated circuit factory as even the smallest speck of dirt can ruin the job. Because you have to use oil rather than grease there is no way (with many models) to put the balls in place whilst you assemble it. Maybe consider booking a flight on whatever replaces the Space Shuttle so that you can do it it zero gravity. That will probably work out easiest.

As for adding an after-market seal, the slightest bit of drag, i.e. that introduced by the seal, will cause the freewheel to not spin freely and you will end up with your chain wrapped around your tyre and chainstay the minute you ease off the pedals.

If you have got a single-speed freewheel then the outlook is a bit more optimistic. You can clean it out and put it together again using oil instead of grease. If you don't over-tension the pre-load for it then it should work fine to give many years of trouble free operation. If you are on multi-speed though, just give up. Admit to being merely mortal. Bow to those Japanese factory workers and feel humbled by their engineering genius.

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Sheldon Brown describes how to reassemble a freewheel: sheldonbrown.com/freewheels.html#disassembly –  Daniel R Hicks Aug 9 '11 at 11:11
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And I have rebuilt 7 speed freewheels. They are tricky, but serviceable. –  zenbike Aug 9 '11 at 12:38
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"...end of" what exactly? Your opinion on the matter? I agree as it happens, that it is a waste of time to do it, especially on a part that is typically that cheap to replace. But you are incorrect in saying that you should use oil rather than grease. Rather say that you should use the correct grease. And you didn't say you had done them but would recommend against it. You said it wasn't feasible to do it. I happen to think the idea of making a sealed freewheel homemade is a bit silly, as SS versions at least are available, after all. But that isn't what was asked by the OP. –  zenbike Aug 9 '11 at 14:29
    
@ʍǝɥʇɐɯ there's only one model shimano makes for my system. and it's awful. the high end models ($50 are no better). and redoing my freewheel twice (used grease the 1st time) took me around 3-4hours. but the question is about home-made oil seal. –  gcb Aug 9 '11 at 18:11
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@gcb Shimano only make low-end freewheels and those are for low end bikes, e.g. with pressed steel hubs. Maybe in the NOS eBay market you could get an early 6 speed HyperGlide for your bike - that might be a better start. Seals existed in the era of the freewheel on the b/b etc but never on freewheels. They only came along with the freehub. 3-4 hours is a long time to miss-assemble something b.t.w. –  ʍǝɥʇɐɯ Aug 9 '11 at 21:54
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up vote 0 down vote accepted

No ready-made product. No previous try to make one.

Easier, cheaper to buy a new one every couple years.

possible solution can be the white industries' one-speed and somehow convert it to hold a cassete.

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As far as sealing a freewheel, I've always used a rubber "o" ring fitted to the outter recess of the freewheel. It keeps dirt from collecting in the groove.

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how do you prevent the o'ring from braking the freewheel rotation? –  gcb Jan 20 '12 at 18:20
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