Dura Ace 7700 Freehub service...possible?

[teamgomez]

After finding a thread describing the freehub removal, I'm trying to figure out how to completely disassemble a 7700 freehub. I've removed the rubber gasket that mates the hub to the axle body and can see the 30 or so small bearings, but just how does one get at the pawls/break down the freehub?

One of my freehubs (very low miles) gives me a faint 'metal on metal' feel during freewheel...and every other 'pawl' detent isn't a click...it is a distinctly different feel/sound. Would really like to get in there to see whassup. I put about 6 drops of light oil on the bearings/reassembled and the suspect feel is still present.

Appreciate the help!

~John

 

[tafi]

Once you have undone one of the cones and found the supporting bearings, you need to take the bearings and the axle out. Behind them on the drive side is a stumpy looking hollow bolt which holds the freewheel/cassette carrier onto the hub body. Not certain but I think it takes a 10mm Alen key.

Importantly, I can't remember whether it is left or right handed.

The exploded diagrams are available on the shimano site, it is the "body fixing bolt":

http://techdocs.shimano.com/media/techdocs/content/cycle/EV/bikecomponents/FH/EV-FH-7700-1654_v1_m56577569830610236.pdf

It can be a ***** to undo. Often it's easier when the hub is built into a wheel, then you just put the allen key in a vice, put the wheel on top and twist.

As far as rubbing noise is concerned, you will find out if anything is wrong shortly...

 

[alfeng]

Once you have undone one of the cones and found the supporting bearings, you need to take the bearings and the axle out. Behind them on the drive side is a stumpy looking hollow bolt which holds the freewheel/cassette carrier onto the hub body. Not certain but I think it takes a 10mm Alen key.

Importantly, I can't remember whether it is left or right handed.

Yes, you will need a 10mm Allen Wrench to remove the hollow bolt ... PLUS, a lot of leverage. The bolt has standard, "right hand" threading.

It is a lot easier to cannibalize a Freehub body from another Shimano rear hub than to service a Shimano Freehub body -- I believe that special tools are required. A canniblized Freehub won't be Titanium, but it won't weigh that much more AND it will be a lot less expensive.

If a cannibalized hub is the source for the replacement Freehub body, then it must be partially laced otherwise you'll never achieve sufficient counter-leverage.

 

[teamgomez]

Already used the 10mm to get the freehub off...thx for that note, tho. It was a bit of a challenge to find that bit of info but I was able to locate that tidbit in order to get the freehub off and I'm stumped on freehub itself.

Concur on the special tools...but I can't help but wonder why nobody has posted a rebuild DIY yet. I've been into my Mavic freehub more times than I'd like to mention b/f I got it dialed in to perfection and I gotta believe that the pawls in the DA freehub need some TLC at some point. Are folks simply using the freehub as a consumeable???

 

[alfeng]

Concur on the special tools...but I can't help but wonder why nobody has posted a rebuild DIY yet. I've been into my Mavic freehub more times than I'd like to mention b/f I got it dialed in to perfection and I gotta believe that the pawls in the DA freehub need some TLC at some point. Are folks simply using the freehub as a consumeable???

Well, the modular, non-user serviciable Freehub seems to be an extension of Shimano's general design philosphy ...

Undoubtedly, to facilitate assembly ... and, by my reckoning, the general design philosophy is reason that Shimano came to dominate the OEM market.

Non-servicable modules also facilitate maintenance for race mechanics because the mechanic just substitutes components rather than spending time rebuilding stuff.

If you think about it, the Shimano Freehub design isn't really that different from the philosophy behind Freewheel design where disassembly-and-reassembly was rarely a worthwhile endeavor.

Regardless, now you know ... if you want a high-zoot hub that can be user-serviced, then you should look at either CAMPAGNOLO (when applicable) or DT (DT hubs are available with either Campagnolo or Shimano compatible splines), first.

 

[Peter@vecchios]

Already used the 10mm to get the freehub off...thx for that note, tho. It was a bit of a challenge to find that bit of info but I was able to locate that tidbit in order to get the freehub off and I'm stumped on freehub itself.

Concur on the special tools...but I can't help but wonder why nobody has posted a rebuild DIY yet. I've been into my Mavic freehub more times than I'd like to mention b/f I got it dialed in to perfection and I gotta believe that the pawls in the DA freehub need some TLC at some point. Are folks simply using the freehub as a consumeable???

You can remove the very top plate and expose the freehub guts(left threaded, BTW), including the really antiquated 2 pawl system but DON'T DO IT. Almost impossible to get the 1/8 inch bearings to stay in place, in order to get the thing back together.

 

[teamgomez]

Almost impossible to get the 1/8 inch bearings to stay in place, in order to get the thing back together.

That about wraps it up....searching for 1/8" bearings that have rolled off the back of the workbench would likely induce a tirade unsuitable for the tender young ears of my neighbor's children.

Case closed!