Modern Vespa

Hey folks,

So earlier this week I heard some strange sounds coming from the rear axle of my gts--imagine a big, heavy metal door creaking on its hinges and you've got the idea. I had some people at a fairly reputable shop take a look at it, and the mechanic said that the axle/drive shaft will probably need to be replaced. His evidence: after taking off the rear axle nut and removing the base plate, the bronze/gold-looking nut would not slide off the axle, which he explained was due to there being a ridge on the axle. He thought that the main nut may not have been tightened all the way the last time it was put on, which would have somehow caused there to be too much horizontal play in the wheel, thus damaging the axle. The scoot's been riding fine for the last couple of weeks, but he encouraged me not to ride it around, just to be safe.

Has anyone else ever had problems like this with the axle or nuts? I searched and found some threads of similar problems, but couldn't find any that offered good explanations for the damage. Any ideas as to what may have caused it?

Thanks,
Scott

P.S. Just out of morbid curiosity, does anyone know how much the drive shaft will cost to replace?

It sounds like the axle was reassembled at some point with the spacer and washer reversed--the damage described is consistent with that.

Don't know how much for the axle, but make sure the spacer, washer and nut get replaced as well to avoid damaging your shiny new axle.

P.

Get a second opinion.

The internal transmission bits are very robust. Look more closely at the 'swingarm' bearing and all those bits before undergoing more expensive surgery. But - he may well be right, so start saving.

I too have discovered a ridge on the axle.

I had some BAD noises coming out of that area, I thought it was something in the final drive box.

It turned out to be the bearing in the 'baseplate', as you have called it, had failed.

I believe it has been on the way out for some time.

I noticed at Amerivespa that my rear wheel would not spin freely, some folk suggested my rear rotor was warped.

After replacing the bearing (and ignoring the ridge and just putting it back together) my rear wheel spins like a spinning thing.

I believe the failing bearing wore the ridge in the axle.

I'm not sure what you mean by the bronze/gold-looking nut.

On mine there is the nut cap (that the split pin works with) , the nut, a spacer, the baseplate.

Then when the wheel is removed there is another conical shaped spacer.

Mine all went back together fine, I was thinking I'd file the ridge flat but everything seemed to fit just fine so I left it.

If that was the right thing to do or not, I'm not sure.

I have mentally prepared myself to replace the axle, from the manual it looks like something I could do with basic tools.

In the meantime I'm just riding it.

marc-

By "bronze nut" I indeed meant the conical spacer past the base plate, or whatever that thing is called. I was the last one to put all of the parts back together, but I'm 99% sure that they were replaced in order.

Anyway, the mechanic did notice that the wheel had trouble spinning and thought that the bearing in the base plate had failed, so maybe I'll suggest just replacing that for now. I don't really have the money to do major work on it, and as of now it seems to be running fine, although probably not as smoothly as it did way back when.

Thanks for the info!

Scott

I found a shop (a bearing supply house) that sells the identical bearing for about 14 bucks. I preemptively replaced at 8000 miles on one of our scooters, and am prepared to replace the other at the next rear tire....12,000 ish.

It IS a standard bearing size/configuration/manufacture...and can be done at home. Mine required some heating to remove the old one (and some "gentle" persuasion) and some freezer-time to shrink the new one to simply drop into place.

Check your local\ bearing suppliers, or Vespa parts-counter.....but there WILL be a price difference. In any event, it's probably cheap insurance and worth doing every so often.

Bearing #6303 double sealed (not double shielded)

http://www.mcmaster.com/#6303-ball-bearings/=3u270m

47mm outer x 17mm inner x 14mm width.

There are a couple types.

There's the standard (about $10) and one that allows a little lateral movement of the inner race (about $20).

I got the latter, I don't know if it was necessary or prudent.

Last rear tired replacement I had a hard time getting the spacer off the axle. A little force and it came off, but there was a very slight ridge on the axle, which I sanded off. I'm ready to replace my rear tire again soon, so will see if the problem is still there. Not sure what would cause the ridge. I'm the only one that removes the rear tire. I just thought it was the miles on the scooter or the 2-up riding we do, generally over loaded on a trip.

I think you're talking about the swingarm plate. Can we see a picture?

The conical spacer sits inside the bearing there in the swingarm plate.

It was that bearing (#6303 double sealed) that was shot on mine.

Yep! That's what I was talking about. I think I'm just going to ask the guys to sand down the ridge and replace the main bearing. Hopefully that'll fix it for now.

About free-spinning the rear wheel--mine and my wife's GTS both have a rear wheel that spins freely for about half the rotation and then has friction on something, for the other half. When I pointed that out to a mechanic early on, he said that's normal. I assume it comes from the brake disc. My GTS still displays that behavior, after over 26K miles, and my wife's GTS has it with over 5K on it.

Is it really normal? Do your GTSs display that same behavior? Put it on the center stand and rotate it to find out. Please report here.

Back to the OP's problem. Just to be sure we talk about the same things, here are three views of that rear axle, in different stages of assembly:



Nut and spacer still on the axle




Nut and spacer removed. The bearing in the plate is visible





The conical centering spacer is visible.

When you reassemble the parts, make sure you add either anti-seize or an installation oil to the axle, under the bearing, so it won't stick the next time you need to remove the plate.

If you do a DIY replacement of the bearing, make sure you get the correct version. Obviously, there are several that fit, but I'd say only one that is right.

Edit: somebody beat me to it, with my own pictures

Mine only ever used to spin halfway, some thought I had a warped rotor.

It has been that way for a long time, years even.

With the bearing change it spins four or five revolutions with the same force exerted.

There seems to be two types of #6303 double sealed, standard and precision plus.

Both have the same load rating and rpm rating (11,000 rpm)

I installed the precision plus as that's what they gave my wife when she went out to the bearing store (via the liquor store and the firewood yard... )

To paraphrase McMaster Carr:

'While designated as ABEC-1, these bearings are actually made to higher-precision ABEC-3 standards. They handle radial loads, small amounts of angular misalignment'

I borrowed your pic from my thread about the ridge in my axle, to answer jess's query, thanks!

windbreaker: I'm not sure what this means--you and your wife's scoots are probably in better shape than mine--but with a good, strong push I can get about 1.5 to 2 revolutions out of the wheel. However, it does not spin on its own while the engine is idling, so I think something's up.

I'm going to buy a replacement bearing sometime today and install it myself. I think, like Turkman, that the ridge may have developed as a result of riding two-up (my pillions are always rather...large). Anyway, is there a special technique I should use to get the old bearing out? Just tap with a hammer? And do I need to lube anything up with grease/anti-seize when putting it back together?

Thanks guys!

Scott

I think all the info you need has been already written in this thread.

Thanks, Jim--you're right. One more question, though? What kind of grease should I use for the axle? I have a tube of silvery-gray anti-seize--is that the right stuff, or do I need something different?

That sounds like Optimol, as used by BMW. Very expensive, but a little goes a long way. I use that on items that'll get very hot (exhaust nuts etc) - otherwise I tend just to use a copper-based grease (Coppa-slip or equivalent).

So after taking apart the wheel-bits and replacing the axle bearing, I realized that the spacer between the axle nut and the metal plate is missing--like, entirely. I don't want to point fingers, but I wasn't the last one to take those pieces apart, so someone else forgot to put it back on when reassembling the wheel.

The wheel spins a bit easier now that the bearing is replaced, but it still sticks. Would the missing spacer having something to do with this?

Most likely yes. The nut is of a wider diameter than the spacer, meaning, it may interfere with the side of the bearing.

Get that spacer from your Vespa dealer, install it, and then check if there is still abnormal friction.

What's more important, without the spacer, you might not have enough threads under the nut to hold it in place safely. This is serious.

PS: looking at this picture...


...it looks like the nut can't even reach the bearing, unless you flatten the threads with the cylindrical part of the axle.

It really needs that spacer!

Called every shop in the area, and none of them had the spacer in stock, so i ordered one from Motosport Scooters. I think you're right that the nut would interfere with the bearing without the spacer--I'm imagining all those little bearing balls smushed against the inside edge of the rubber seal by the pressure. Awesome.

Once when a shop was putting on a new rear tire for me, put the spacer and other bits on incorrectly caused damage to my bearings. Missing the spacer could definitely be the problem.

I hope that's all it is. I'm bummed, though, because the axle is already damaged. I'll do my best to sand it down, but like...ugh. Oh well.

I don't think so anymore. The nut would not reach the bearing, the cylindrical part of the axle is as thick as the threads, so the nut won't be able to carve into it to reach the bearing.

I think what's happening is that the plate and the bearing are sliding along the axle, because the nut can't stop them. This would result in a less than stable conduct of the rear wheel/rear end of the scooter, but not necessarily for noises (unless the sliding around on the axle and hitting the conical spacer caused the noise).

I would have a very serious talk with the mechanic who forgot to install the spacer.

I just re-read your OP and found this: That's exactly what I was now suspecting: the nut started to cut into the axle, damaged its threads, why it would not slide off the axle later. Lateral play of the bearing caused the noises somehow. Whoever forgot to install the spacer has to pick up this bill!

Well, I got the new spacer in the mail today from Motorsport and put it on. Turns out, the old one was there, but it had been installed behind the muffler support plate, instead of in front of it.

But anyway, I sanded the ridge out of the axle and put everything back together. The wheel spins a little easier now than before, but there's still some friction so that it doesn't spin freely when on the center stand and the engine's idling. Oh well. I guess it's something with the brake.

Thanks for the help!