Rethreading rear axle, replacing nut

[hypophthalmus]

My rear fork is stuck to the rear axle shaft. I tried lightly hammering the shaft to loosen it, but I think I just bent the end of the threads. And messed up the threads of the axle nut while I was at it.

Does anybody know what size die I'd need to fix the threads on the axle? And if I can use a non-oem nut?

And possibly how to loosen the fork, which is still stuck.

[hypophthalmus]

I'll answer some of my own questions. It appears to be 16mm. Using a caliper, it looks like a 1.25mm pitch. But it's hard to be sure, since that's so close to 1.0 and 1.5.

I've tried letting spray lubricant sit, but I'm not sure it's doing much good. I have a map torch, but that would burn up the bearing dust seal.

[hypophthalmus]

Still not sure if just a regular m16 flange nut would work though.

[hypophthalmus]

I ordered this, http://www.ebay.com/itm/252512932201 , honda part 90305-ME5-003 . It starts with the same five digits as the kymco part, and looks identical I think.

There's the possibility that the pitch and length are different I suppose. I'm hoping not.

[hypophthalmus]

Aaaand, to reply to myself for the last time today, there isn't a dust seal after all. Somehow I didn't realize I was looking at the bearing, which needs to be replaced anyways. So I'll try torching it.

[mrbios]

My rear fork is stuck to the rear axle shaft. ...

Don't feel bad.  I ran into the same problem with my 2005 Grandvista 250 around 8K miles or so and it was my first time removing the rear wheel on a scooter vs all the motorcycles I had owned that had a removable shaft.  From the factory the spline is not packed with grease probably just machine oil.  Overtime it rusts slightly.  The secret is to lean the scoot on the left side - you could lean it against a wall and put a rug or blanket in between to prevent scratching. Then shoot WD-40 or any light penetrating spray.  After letting it soak for a few minutes put the nut back on and tap it very lightly then attempt to work the wheel off.  You could also reassemble and drive it for a day or two.  Then the wheel should come right off.  After getting it off and discovering I bent the threads slightly I lubed the spline with loctite brand antiseize and grease and also greased the nut and threads and was able to get the new tire /wheel back on.  I came close to stripping the threads.  After that I removed the wheel 4x - two flats, and two new tires each time with no problems.

TIP: Any time you use a die to re-cut the threads the size will be smaller and the next closest size will be SAE or English threads.  If SAE then metric so you can use an SAE die instead and purchase a nut to match that thread pitch.  If the threads just need reshaping then you could try the same metric size and thread pitch.  Using the nut you could go to a machine shop or Grainger to get help determining the thread pitch and exact size of the nut.

[hypophthalmus]

I guess it's probably a good idea to put a light coat of lithium grease like you would with the front axle?

I'm not sure I understand what you're saying with recutting the threads, which makes me nervous. I think the only part that needs cutting/reshaping is the very end where it got bent by hitting it with the hammer. It doesn't look like anything else got damaged by trying to thread the nut back on, although the nut threads are messed up. So I was hoping that using the same size/pitch die would straighten out or cut the end and then just follow the rest of the threads.

[hypophthalmus]

Success getting it off.

Yesterday I used liquid wrench lubricating oil to no effect. This morning I took a torch to it, stopping when the part of the fork around the rubber bushing became too hot to touch (didn't want to risk damaging the bushing). Still stuck. Tried WD-40, still stuck.

I was reluctant to try the hammering with the nut on trick, but decided that it was my only option. It took a good deal of pounding with a 5lb sledge hammer, but I got it off. It didn't actually loosen and and come free, but rather was hammered off tiny bit by tiny bit. Thankfully the threads don't seem any worse for it.

It looks surprisingly not corroded. I wonder if the inner race of the bearing deformed a bit because the bearing was going. Although it's not at all obvious that the bearing is bad now (besides being burnt), there seemed to be a good deal of play when it was installed.

[mrbios]

Success getting it off.

Yesterday I used liquid wrench lubricating oil to no effect. This morning I took a torch to it, stopping when the part of the fork around the rubber bushing became too hot to touch (didn't want to risk damaging the bushing). Still stuck. Tried WD-40, still stuck.

...It took a good deal of pounding with a 5lb sledge hammer, but I got it off. ...

Congratulations - what a great feeling to have that wheel off!

When I read 5lb hammer - I said OMG out loud lol.  I have a 4 pound hammer so I know how hard that hits.

Great info thanks for sharing.  If you have an angle grinder with a flat wire brush you might want to wipe an polish up the splines.  I'm really surprised at the effort it took.  The torch is another tool that can be very helpful if used with care.  Btw, home depot sells a small black "Flame cloth" for $15 in plumbing dept that can withstand being hit with the torch flame it will actually turn red without burning.

When installing the new bearing you can put the new bearing in the freezer lightly head the wheel and grease the outside of the bearing and then drive it in with a block of wood.

Can you post some pictures - I would be great to see.

I found that the spline shaft & wheel is a very close fit.  I would also use a small wire brush inside the wheel as an debris can jam the spline threads.

[hypophthalmus]

It is a great feeling, especially without having damaged anything further... I hope. Well, actually the wheel's still on since I still need to take the shock off, and the plastic. Since I need to wait for parts anyways, I guess it's a good time to do general maintenance anyways though.

Actually it was a four pound hammer. But yes, I was also surprised that it was so difficult. Even more so after seeing how the surfaces were so smooth.

Here's the rear fork with the bearing:
http://earthwoodjoinery.com/random/photo/scooter/rearwheelstuck/bearing.jpg
I think the dark stuff on the inside of the bearing is burnt spray oil from torching it.

And here's the rear axle:
http://earthwoodjoinery.com/random/photo/scooter/rearwheelstuck/axle.jpg
Past the obvious corrosion on the shaft is where the bearing was sitting, on the clean looking spot. You can see on the end of the threads where I hit it.

And here's the axle nut with the damaged threads:
http://earthwoodjoinery.com/random/photo/scooter/rearwheelstuck/nut.jpg
It was cleaner than that when I tried to install it.

[mrbios]

Cool pics.  Threads look good.

[Redk]

WoW !

That reminded me of the olde days when my 2400 baud modem stepped down to 1200 baud because line quality was so bad.

Definitely could use some lubricant in there.

The threads on the axle do look coarse. I would use the silver kind of anti-seize on it to prevent it getting worse.

That nut can be re-purposed as a fishing weight, if you are a thrifty kinda person.
If you have somehow re-used it, purchase a replacement axle and nut in advance.
redk

[hypophthalmus]

What sort of lubricant should I use for the axle? Lithium grease? Should I use anything on the splines?

I'm definitely not planning on reusing the nut. Why are you suggesting replacing the axle though? I was planning on repairing the dinged threads and keep using it. It's pretty expensive I think (possibly around $60), and complicated to replace.

I might try using a dry teflon spray to protect the threads, since I have it on hand and it claims to be good for corrosion resistance.

[hypophthalmus]

I'm noticing now that with the wheel pushed in all the way, there's play in every direction. That's probably not normal, right? I'm wondering now if maybe the fork bearing didn't get messed up because the wheel was tightened at a slight angle.

[mrbios]

I'm noticing now that with the wheel pushed in all the way, there's play in every direction. That's probably not normal, right? I'm wondering now if maybe the fork bearing didn't get messed up because the wheel was tightened at a slight angle.

It is ok to reuse the nut as long as you lube the threads.  I reused mine with no problem.  I would replace the bearing on the bracket (the part you call the rear fork).  Wipe it off and write down the numbers - any place that sells bearings can get you one based on those numbers.  Use antiseize on the spline shaft (silver looking oil & graphite paste) available at any auto store.  You can also apply any silicone based grease which repels water on the spline.  The wheel needs to be tight once the nut is on with no side to side play.  Once you tighten everything up the play will go away.