Home-made sealed freewheel? 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:


remove wheel
let if lay down with the freewheel cogs on top
use a spanner tool to remove the cap on the freewheel
drop oil in there
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.
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.