Bicycle Mechanics - Disassembly of Shimano Ultegra Freehub?

Ok after 5000mi this year, my Ultegra 6600 freehub is making noise and I want to open it up, clean & lube it. Anyone have any experience with this? Is it a nightmare waiting to happen or not so bad? I'm very mechanical but any tips would be appreciated.

Thanks!!

Tiny bearings and thin shims....

It is pretty hard but possible, question is why?

Instead you can pull it off of the hub with a 10mm allen and remove the rubber seal from the inboard side.
Soak that sucker and flush, then blow out any solvent spinning the freehub to clean the pawls.
You may need to repeat.
The body should feel kinda loose and sloppy at this point and spin very freely.
Here i usually take a small bead of Triflow grease(not lube, although i know a guy that uses Phil's Tenacious Oil for this) applied to the gap just above the bearing race and blow it in with the compressor and repeat on the other side, wrapping the thing in a rag so i don't blast myself with the blowback.
Very little grease is required and too much will prevent the pawls from engaging.
This can also make the hub silent, which is kinda nice actually.

Of course best solution is that the new ones are pretty reasonably priced for the peace of mind they provide.

I do pretty much what Hawaiiwrench described but I don't solvent wash the freehub body and I do use oil (Tri-Flow to be specific), not grease, to lube it.

My Shimano freehubs are very quiet with this treatment and I have one Dura Ace freehub with 50,000 miles that still works perfectly.

They are a pain to get apart and back together, although not nearly as much of a pain as an old freewheel. Flushing it out then putting oil (cold weather) or grease is far easier than actually disassembling them.

If you want to do it, check this article. It's about winterizing but the disassembly/reassmbly is the same. Instead of grinding down a freewheel tool, I filed a piece of flat bar for the toprace tool.
http://www.icebike.org/Equipment/freehub.htm

I do like Hillrider says, and I do use Phil's Tenacious Oil, and the other thing I would add is to only work the oil in from one direction. That way, any grit gets flushed out the opposite side. If you put in oil/lube from both sides, you are driving all the grit into the mechanism. Instead, go from from one side and keep working the oil until it starts coming through to the other side.

Take it to a shop that has the tool whose sole purpose is to pump lube through freehub bodies. It forces grease through from the wheelward side, pushing out all of the gunk, and negating the need for solvent (which causes trouble if you don't get it all out). If you remove the freehub and bring it in, they shouldn't charge you more than $10, this process only takes a few minutes. Also, Phil Wood Tenacious is perfect for this job.

Lay the wheel at a 45 degree angle and work in alot of NON-wax based chain lube as you spin the freehub unit backwards. Keep adding lub unitl the sound changes. Let it sit for awhile and drain out the back. You may want to stuff something into the spokes to absorb the lub as it drains out.

Repeat until the drainage looks clean. If you have a freehub with the rubber seal you'll have to lean the freehub in such a way that the lub drains out the front side.

Ok after 5000mi this year, my Ultegra 6600 freehub is making noise and I want to open it up, clean & lube it.

A worthy intention.


Anyone have any experience with this?

Yes.


Is it a nightmare waiting to happen or not so bad?

Not a nightmare, a tad more difficult than servicing a wheel bearing. Somewhat fiddly, and bodies aren't that pricey, but very doable.


I'm very mechanical but any tips would be appreciated.

Here's (http://happymtb.org/forum/read.php/1/144572) a photoguide on how to do it. The language is Swedish, but there are plenty of pics.

Key points translated:
it's recommended to replace the ball bearings, you need 50 balls in size 1/8".

Removing the dustcap w/o warping it too badly is often the hardest step. Gentle prying with wide screwdriver is the suggested method.

Loosen the Allen bolt holding the body to the hub just a little before you hit the bearing cup. Once the cup has broken loose you can then remove the Allen bolt all the way.

You need a "special" tool measuring 29 mm wide and 2 mm thick to loosen the bearing cup that holds it all together.
I used a file that I thinned out a little at the corners with a bench grinder, the guy who wrote the guide used a cone wrench with the prongs cut off. Aluminum won't cut it, but otherwise it's not that picky. Removal is clockwise!

Sticky grease is recommended to hold the ball bearings in place during reassembly, while something more fluid is recommended for the pawls.

Let me know if you need anything more translated.

Well, Thanks everyone! I think I'll begin with the flush and lube method and see how that works 1st before I go for the total disassembly, no need in tempting the Fates!

7 months later and the flush and lube worked until about a week ago... Time to do it again - I thought anyone who is reading this might want to know. The flush and lube is isn't foolproof and it takes a couple of tries but it does work.

I can't believe no-one mentioned a Morningstar Freehub Buddy (http://www.morningstartools.com/freehub_buddy1.html) - a perfect tool for purging out the old crud and injecting in the new stuff.

I use a light degreaser from one side only, not submersion, and then I use a freewheel injector with Phil Wood grease. After greasing, I add a light lube to make a slurry. The freehub is nearly silent and works great. When you start to hear the pauls again, it's time to clean and lube.

7 months later and the flush and lube worked until about a week ago... Time to do it again - I thought anyone who is reading this might want to know. The flush and lube is isn't foolproof and it takes a couple of tries but it does work.

Serrotta Steve, what type of lube did you use? I kept a Bontrager freehub alive with Phil Wood Tenacious Oil, but found that the I had to relube at a frequency that I deemed "not fun anymore" and just replaced it.

In case you don't want to have any more fun by removing & lubing the freehub, you can get a new
Shimano Ultegra 6600 body for under $40.

http://www.bikesonline.com/Ultegra-6600-10-Speed-freehub-body.htm

I can't believe no-one mentioned a Morningstar Freehub Buddy (http://www.morningstartools.com/freehub_buddy1.html) - a perfect tool for purging out the old crud and injecting in the new stuff.

I can. I emailed them once. Never heard from them. If they ever get real and take PayPal, I might check it out. As is - they don't trust me. But I should send them my money?? No return email??

FAIL.

I can. I emailed them once. Never heard from them. If they ever get real and take PayPal, I might check it out. As is - they don't trust me. But I should send them my money?? No return email??
FAIL.
You judge Paul from ONE e-mail that might never have arrived at his place? I've dealt with him for years and have never had an issue.