Hub Dilemma

[Richard]

My kid's friend used a drill to tighten the disc retaining bolts on an XT hub. The threads are in the condition you would expect. Should I:

1. Look for longer retaining bolts assuming that the threading goes deeper than the length of the OE? If so, what is the size and thread pitch I should buy? or;

2. Buy a tap and see if I can chase OE threads and use the OE bolts? or;

3. Buy a tap and use a larger diameter bolt? If so, what size for this operation? or;

4. Another idea?

Any help would be appreciated.

[.RJ]

chase them with a tap, first, but you may be buying a new hub.

[Mikej]

I would worry about removing the bolts first. How jagged up are the hex inserts? The disc mounting hardware holes generally tap through.

[Richard]

He used a torx bit, so my tools will still get purchase. Mikej, are you saying that a longer bolt should work? The OE looks to only go about 1/2 into the hub.

[Peter P.]

Deleted duplicate post.

[Peter P.]

They're M5 bolts. Replace them.

Re-tap the original threads.

First use a TAPERED tap, which will give you the best chance of restoring the initial threads.

Follow that with a PLUG tap, because presumably you'll be able to catch the tapered tap threads.

End with a BOTTOMING tap, which will tap as far into the hole as possible.

Use Loctite 242 on the full length of the threads. It will help fill any gaps in the munged-up threads if the taps don't fully restore the threads.

Finally, take away the drill from your son's friend.

[robt57]

Did he strip the heads driver portion of the bolts, or spin out the bolts in the alloy hub striping those threads?

[Richard]

Thanks Peter P. Should I look for longer M5 bolts to take advantage of un-munged threads? Mikej...he stripped out the threads. Heads are ok. Too bad. I the heads were bad, that I could deal with.

As for the drill, I'll have my son melt the plastic casing.

[Peter P.]

Originally Posted by Richard

Thanks Peter P. Should I look for longer M5 bolts to take advantage of un-munged threads?

Wouldn't hurt. If they're too long, you could always hacksaw off the excess and restore the threaded end with a file. Get a couple M5 nuts to help hold the bolt in a vise.

McMaster.com should have the bolts you need if your local shop doesn't stock longer bolts.

[Richard]

Peter P.

Thanks for the detailed methodology. Followed it and used M5 14mm bolts to replace the M5 10. Fit with no cutting. All is well with the world (well maybe not), but all is well with the hub. Again, thanks.

[dddd]

This is a good place to use blue retaining compound.

Some hubs will allow adding a nut to the far end of the bolt, using a longer bolt of course.

I've used 5.5mm (and equivalent-size SAE#12) bolts to repair assemblies with stripped 5mm threading. Bottle cage bosses and front derailer arms come to mind.

The disc brake application requires use of high-quality steel bolts.

I would hesitate to go oversize where so little redundant metal often (doesn't) exist on the hub shell.