Rear cassttee slipping - advice needed

Hiya

I checked the search but couldn't see anything suitable, please direct me to the correct thread if this has been asked before.

My daughter has a lightly used Gary Fisher mountain bike and the rear cassette is slipping. You pedal forward and the cassette spins but doesn't "drive" its as if you are pedaling backwards with a free wheel. Sometimes it engages and works as it should but most often it doesn't - there is no obvious point where it engages, it either does or it doesn't.

I've removed the cassette to investigate but can't see anything obvious. The splined cassette holder is fine with all teeth intact. When rotating the cassette holder by hand it will move forward or backwards when it should only move forwards. As above, it'll engage sometimes but not often and when it does its not in a set point.

I've removed the axle but this doesn't let me get to anything else, I want to remove the splined carrier as the problem seems to be with this. I can't see how to remove the carrier, there aren't any bolts or screws to undo - how does it come off?

Has anyone else experienced anything like this? Is the wheel fubarded?

Any tips, hints or ideas are very welcome.

Hub is a low end Shimano - FH RM-30.

Thanks in advance!

Sounds like the freewheel pawls aren't engaging. You could always try spraying some GT-85 or something similar into any small openings you can find on the freewheel body, and seeing if that'll get the pawls moving consistently again. Otherwise new freewheel body needed (typically remove the old one by undoing a 10mm allen bolt (you'd need to remove the axle to access it); or hub/rebuild; or wheel...

Heres the Shimano tech doc for that hub, the 10mm allen key fits into part 11 on the exploded view.

http://techdocs.shimano.com/media/techdocs/content/cycle/EV/bikecomponents/FH/EV-FH-RM30-8S-2388B_v1_m56577569830800934.pdf

New freewheel is pretty cheap if it does turn out to be borked.

http://www.petracycles.co.uk/shimano-spares-fh-rm30-speed-complete-freehub-body-p-6017.html

Thanks both!!

I have taken it apart and rebuilt and it seems to be working fine. It was the 10mm allen key to get the free wheel body that I couldn't see (and didn't know about). Once you'd pointed it out I was able to take it off and re-seat it.

Thanks very much for your help, it really is appreciated.

Cheers

Good news!