Broken feewheel again

naked_draughtsman said:

I put a Shimano megarange freewheel on my cheap MTB and the 'freeness'
of it has been reducing over the last few months. Someone on this NG
suggested soaking it in sunflower oil which did the trick, but only
for about 6 weeks.
I've since done the same again which revived it but only for 2 weeks
this time and it's now got to the point where freewheeling down a hill
pulls the chain over the top, stretching the springs on the deraileur
so when I try and pedal again I have to take up considerable slack in
the chain.

How about first soaking and flushing in solvent, then soaking in light
oil? ...An oil that's intended for mechanical things rather than
cooking!!! Sunflower oil is bound to become too gunky after a while.

Ignore advice from chefs in future ;-)

There could be more of a fault than mere stickiness, though. I normally
associate sticking pawls with lack of drive (freewheel mode all the time)
rather than the other way round.

Quoted message said:

I'm swapping it for the original freewheel as soon as it stops
raining. I've not exactly looked after the megarange one as if it
were offspring, but should it have failed so quickly? (only 7-8
months ~ 600 miles use)

Definitely not.

~PB

naked_draughtsman said:

I put a Shimano megarange freewheel on my cheap MTB and the 'freeness'
of it has been reducing over the last few months. Someone on this NG
suggested soaking it in sunflower oil which did the trick, but only for
about 6 weeks.
I've since done the same again which revived it but only for 2 weeks
this time and it's now got to the point where freewheeling down a hill
pulls the chain over the top, stretching the springs on the deraileur
so when I try and pedal again I have to take up considerable slack in
the chain.

I'm swapping it for the original freewheel as soon as it stops raining.
I've not exactly looked after the megarange one as if it were
offspring, but should it have failed so quickly? (only 7-8 months ~ 600
miles use)

Is has had a tough life. If you had used it regularely it would have had
an easier life! Now it has been rusting away, with sporadic bouts of
getting wet again. There is a URC rule about bringing bikes in kitchens,
but using sunflower oil without any anti-corrosion dopes is going to far 😉

You might try this, but you need a steady hand.

Clean the freewheel and put the wheel freeheelside up.
loosen the bearingcone of the freewheel with punch and a hammer. The
bearingcone is the ring with two small holes (to set your punch against)
and the Shimano stamp. Is has LH threads so it will have to turn in the
CW direction. Once it moves unscrew it further, while keeping the
freewheel firmly pushed on the wheel (you DONT want 50 odd bearings
jumping out)
Remove the cone
Fill the freewheel with lots of engine-oil (you can carefully turn the
freewheel backwards which helps the flushing).
Replace the cone and knock it tight

--
---
Marten Gerritsen

INFOapestaartjeM-GINEERINGpuntNL
www.m-gineering.nl

"naked_draughtsman" <[email hidden]> wrote in message
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Quoted message said:

I put a Shimano megarange freewheel on my cheap MTB and the 'freeness'
of it has been reducing over the last few months. Someone on this NG
suggested soaking it in sunflower oil which did the trick, but only for
about 6 weeks.
I've since done the same again which revived it but only for 2 weeks
this time and it's now got to the point where freewheeling down a hill
pulls the chain over the top, stretching the springs on the deraileur
so when I try and pedal again I have to take up considerable slack in
the chain.

I'm swapping it for the original freewheel as soon as it stops raining.
I've not exactly looked after the megarange one as if it were
offspring, but should it have failed so quickly? (only 7-8 months ~ 600
miles use)

The freewheel on my bike is bloody ancient (I suspect original) and it still
works fine even though the bearings are noisy (the bearings only work when
they're under no load, so don't worry about it). I'd get the wheel off, get
some brake cleaner or thinners (basically the same stuff), pour or spray it
down the centre of the freewheel and wash out all the sunflower oil. Leave
it to dry out, then put 3 in 1 or motor oil in it. Or use spray grease. I
wouldn't bother stripping the freewheel down as they're pretty cheap items
to buy. Sunflower oil *does* dry up and go gummy, so the pawls are probably
sticking.