jowilson

I took apart my cassette yesterday because I was hearing a slight scraping noise during a back pedal and when coasting. I took out the axle and bearings, took off the cassette and cleaned out the old grease. I read that you can use a 10mm allen wrench to take off the freehub body but the wrench was too small, and my shop didn't have any size larger. I just left it alone and poured a bit of oil in the pawl area and spun it around. It sounded clean so I repacked the bearings and put it all back together, put the wheel on the bike and took it for a spin. When I started pedaling, I heard a grinding noise coming from the cassette, worse than what I heard before. I shifted gears and noticed that it quiets down when I go into the larger cogs, it quiets down and nearly goes away.

I have checked the following:

Chain (for dirt and possible frame contact points)
Wheel Bearings(for dirt and maladjustment)
Derailleur pulleys and adjustment screws
Bottom Bracket (for dirt)
Cassette (for dirt and wear)
Wheel (for trueness)

And they all turned out to be OK so my only guess is that its the pawls are still dirty, but I can't get the freehub off.
This is a SRAM PG850 11-32 cassette on a matching freehub.

Anymore info can be given if required.

TIA,

Josh

samg07094

What does it sound like when you flip it over ?

jowilson

Exactly the same.

tomacropod

Chain routed incorrectly through derailleur cage.

- Joel

jowilson

^^^ Nope. It's correct. I checked that too.

byrd48

You may get the required wrench and remove the freehub body and possibly blow it out with compressed air and re-lube the pawls. You might also check the price on a replacement freehub. Make sure when you take it off that you still hear that grinding noise, something probably worked it's way in there.

Andrew R Stewart 

Perhaps there is grit or rust inside the freehub body. Adding lube, especially if thin, can soften up the factory lube and increase the sound levels. ( This is why a clean but worn chain can sound louder then a dirty and worn chain). If any grit or rust was still inside the freehub body then the rough or noisy results will be more readily heard. A more thorough cleaning (light oil/solvent with air blasting until no more dirt can be seen coming out) then re lubing with a thicker lube (Phil oil) is the best you can do without replacing the freehub body. Andy.

jowilson

I know there is probably grit inside of it, but don't know how to get inside of it. I can't find how to remove it anywhere and I was wondering if anyone on here knew how to remove it.

This is what the inside of it looks like, with the notches inside.

But the 10mm allen wrench that everyone says works is too small for this freehub. Does anyone know how to remove it?

tomacropod

11mm! Looks like you didn't quite get the internals clean there either. Plenty of crud in the cup there still.

- joel

Kimmo

Dunno about 11mm, I'd say 12mm.

There's a dust cover pressed into the front of the cassette body; pop that out and you should see two slots in the edge of the axle bearing cup. That's how you get this puppy apart.

There's a link in my tag to more info. I guess it's not a Shimano hub because it's not a 10mm fitting, but it should be similar enough.

Andrew R Stewart 

Removing allen wrench size is most likely an 11mm. There's an adapter for an 8mm wrench that is common but try to source a real 11mm as it will be stronger. Don't worry about the dust cap on the outer end of the freehub. It doesn't cover the Fh bearings, just the axle bearings. There's a lot of space behind it to flush, soak, blow out the FH with. As I said before you need to soak, flush and blow then repeate until the solvent coming out is clean and the Fh spins withoput any catching or roughness. Only then will lube be the next step. Andy.

J.C. Koto

What make/model of hub is that?