[filly]

Just bought a set of BWW DA/OP wheels. The rear hub is the FH-7850. Immediately noticed it makes an odd "ratcheting" noise when freewheeling only. Not your standard clicking of the pawls, but an oscillating ratcheting noise. Sorry, no better way to describe it. I emailed BWW, and they said it's normal...BS. I took the freehub body off, and I can't see a way to get some lube in the actual mechanisms in there. It seems sealed. Of course, I don't have experience with other freehub shells, so I have no frame of reference.

Also, I've repacked the bearings and such, so that's not the issue. Again, it's only when freewheeling. I've dug up similar issues online, and one guy said he was given a new freehub body to mount on the hub. He seemed to think they were not serviceable...remove/replace.

 

[Mike T.]

Just bought a set of BWW DA/OP wheels. The rear hub is the FH-7850. Immediately noticed it makes an odd "ratcheting" noise when freewheeling only. Not your standard clicking of the pawls, but an oscillating ratcheting noise. Sorry, no better way to describe it. I emailed BWW, and they said it's normal...BS. I took the freehub body off, and I can't see a way to get some lube in the actual mechanisms in there. It seems sealed. Of course, I don't have experience with other freehub shells, so I have no frame of reference.

Also, I've repacked the bearings and such, so that's not the issue. Again, it's only when freewheeling. I've dug up similar issues online, and one guy said he was given a new freehub body to mount on the hub. He seemed to think they were not serviceable...remove/replace.

Paul Morningstar has invented the perfect tool to inject new stuff into the FH and to positively purge the old stuff - the Morningstar Freehub Buddy He has also developed his own lubes for this application. I've used one for years and also on my 7850 DA hubs plus Ultegra.

 

[filly]

in a nutshell, how does this thing work?

 

[filly]

also, do you know if the 7850 is the only shimano FH that uses a 14mm hex bolt to fasten the FH body to the hub? aren't the rest of them 10mm?

 

[Mike T.]

also, do you know if the 7850 is the only shimano FH that uses a 14mm hex bolt to fasten the FH body to the hub? aren't the rest of them 10mm?

You are correct.

 

[Mike T.]

in a nutshell, how does this thing work?

I remove the cassette and axle (really easy on the 7850) and remove the drive unit (14mm allen wrench on the 7850). Paul's unit plugs into the outer end of the drive unit and I use the lube syringe to inject the new lube. This forces out the old stuff and leaves behind the new stuff.

So you need - cassette tool, chain whip, cone wrenches, Freehub buddy, bearing grease, a few spare bearings (for when you lose one). But you should have this stuff anyway.

 

[filly]

yep, got all this stuff already. do i need a morningstar seal, or do you not pry off the original during this process? i guess i need to get the syringe, too, unless i use a tube of gear oil?

 

[Mike T.]

do i need a morningstar seal, or do you not pry off the original during this process?

You don't need the MS seal but the one he sells is a nice aluminum one with an o-ring edge that makes R&R really easy. The original one will pry out with a screwdriver and if you don't go ape and ruin it, it can be tapped back in. The MS one is much nicer though. Just make sure you get the right one as there are different versions.

i guess i need to get the syringe, too, unless i use a tube of gear oil?

Before I got the fancy MS lube (in a plastic syringe) I used a pump style oilcan and injected gear oil. It just needs something with a nozzle on it.

 

[filly]

ok, thanks for the firsthand knowledge.

 

[MarshallH1987]

i've only serviced a 7700 series freehub, but i disassembled it as far as possible and then stuck it in an ultrasonic cleaner to get all the gunk out. I then just kind of shot lube inside spun it a bit to make sure it felt nice and lubed up. Haven't had any issues with it since.