Modern Vespa

In the midst of changing my tires I discovered one of my rear wheel bolts had snapped off and is now stuck in the hub.

Even better, when installing the new front tire I had another bolt snap off as I was tightening it (no torque wrench but I was not going crazy on it).

So now I am missing 1 bolt each from front and rear. Wonderful.

I'd like to ask 2 questions:

1) I assume both the wheel rim and bolts are both aluminum?

2) Is there a perhaps an alternative (stronger, galvanized/plated steel or stainless steel?) bolt replacement that might not snap so easily?

I see Scooterwest sells a "Chrome" bolt set, but I assume this is the same aluminum bolt just with a chrome finish.

Thanks

The bolts are steel.
You may be able to get the old one out of the rear by soaking with penetrating oil and tapping lightly with a hammer axially. That is, if only the head popped off. If the bolt broke off inside the wheel hub, it gets a lot less simple. But penetrating oil and a prick punch to try to get it to start turning is where I'd start in this case.

You could use grade 10 bolts but if it was mine I'd just pop on by a dealer and get 3-4 replacements, with appropriate washers and spacers.

Stainless steel is NOT stronger, in any way other than corrosion resistance. Same deal with chrome really; it's just for looks.

The bolts are not aluminum.
The correct bolt should be automotive strength.

You haven't been bitten by any strange spiders recently have you?

Now that you mention it.... No I'm not sure what the deal was but it really was the icing on the cake.

I'll have my local shop tackle it since both are broken off in the hub.

The standard bolts are more than strong enough to cope with a lifetime of being undone & done up again! Someone has way over torqued those bolts, because they just won't normally break even if tightened a bit too much. Your dealer has a number of ways to get them out but worst case scenario is a new hub required. Hopefully, won't come to that.

Since 2 bolts broke, likely all the wheel bolts are in the same shape. Consider replacing all the front and rear wheel bolts with new OEM ones. Discard the old ones. They are not very expensive.

Bill

☝️What he said.

Agree 100% with Bill on the assumption that who ever over tightened those two bolts also did the same to all the other bolts!

I'm not a big fan of Harbor Freight torque wenches, but even if they are not perfect they have to be much better that just guessing how tight you are tightening things.

There's a good chance someone used an air driven impact wrench like all the car tire shops have.

I don't doubt it, but darn!
It's a, what, 6mm allen key?

To all you HF nay-sayers - the torque wrenches I've had from them have all been just fine thank-you.

OK, some HF stuff is sub-par - but these are AOK in my book.

Not disagreeing with you, BUT....
One day, years ago, I was looking for a breaker bar.
Super simple tool, so I figured, go to Harbor Freight.
The Harbor Freight here had about a dozen of them on the shelf.
Every one of them, and I mean Every. One. Of. Them. was broken.
Most with the working end sheared off, some with bent handles, etc.
I was all sorts of unimpressed not only by those tools, but also by the tools putting broken tools on the shelf.

I really like the H-F motorcycle lift I bought used for $100 though....

Years ago you said - then I'd agree with you whole-heartedly!

But I stand by my review of the torque-wrenches. I've not read one finding of them being more than 5% out, usually much less.

If I didn't already have three Snap-on torque wrenches I would probably go for one of the Harbor Freight ones then maybe use a good fishing scale to double check it to be sure it was at least close.

I mean we are not talking Lunar landing craft here so it it was less than 10% off one could learn to live with that and just adjust the setting to get it even closer.

Say if you wanted to torque a bolt to 100 inch/pounds and you knew the torque wrench was off 10% on the low side just set it 10% higher than spec's."Bob's your uncle!"

And if anyone needs to know how to check the calibration I'm sure someone here can explain a simple way to do it with a good fish scale. Just a little basic math is all that is needed.

I just broke one trying to remove it from a new-to-me MP3. Same bolt part number. Way too tight. Dry. Threads from the hub were galled and partially stripped. No way it was coming out. The hubs are very soft and quite expensive (new). I ended up carefully drilling with cobalt bits and putting in a heli-coil. Not ideal but I know it's there and can be gentle with it. The hole is quite deep so it was necessary to double stack two coils to fill it. The torque spec is only 20nM / 14ftlb that's not a lot. An average person can do double that with a 3/8 ratchet.

I'll buy into the theory that a rattle gun was previously used on the bolts. I had this issue once with my GTS when a local Vespa dealer's mechanic installed the front wheel with a battery operated impact gun. I questioned it at the time, but was told the impact gun had a pre-set torque setting. A year later I found this wasn't true. After two broken bolts were removed, the others were badly stretched. Should have trusted my instincts and re-torqued the bolts when I got home. Or, better yet, just do it myself with a torque wrench to begin with.

The pic is one of the removed bolts...

how be it you know it was maybe 5% off? did you send it to a lab for calibration?

so is your fish scale a calibrate one?

the only way to check the calibration PROPERLY is to have a certified lab in weights and measures check it and adjust if possible.

About a year ago I asked a question about When and when not to use antiseize. I asked it because I just replaced my tires and about to reinstall the hubs and had seen recommendations on using antisieze to ensure you could easily remove the bolts in the future. So the time was right for me to ask. After many post by highly respected (at least by me) MV members, I decided to use antiseize on the hub bolts and I got a calibrated mechanical (not electronic) torque wrench. I've not had any problems and my wheels are still on (tho I think I'll check them tomorrow - thanks for the reminder 8)).

Best
Miguel

You put the square business end in a vice, with the handle horizontal, and hang a weight from it. Pretty simple really...

And when you finish with it each time set it to zero. Have been told that by repeated mechanics and had it reinforced by contractors building a high tension power line across the North Island countryside. I was at a meeting where they were all getting their monthly calibration, and not all passed.

That is one way and if you want to use the fish scale you can use a known weight to test the accuracy of the fish scale. Need to find a weight to test the scale? Take the weight you want to use to a grocery store and have them weigh it on their scale.

ARP makes stainless bolts with a tensile strength of 170,000 PSI. This is roughly equal to a class 12.9 bolt.

Good point. I was basing my own on the typical stainless steel fasteners one would find at a Home Depot or similar hardware store.

Over 30 years ago I wandered in to the local auto parts store looking for a clicky torque wrench. Old Louie Cramer behind the parts counter in his greasy blue shirt with the name tag on front and chewing on the butt of a cigar, gave me the classic fish eye. "Here" he said, handing me a traditional beam type torque wrench. "You don't want one of those clicky things. They don't hold up and can't be trusted. This you can run over and it will still work."

Good old Louie. I'm still using that wrench. Miss that place.

On another point: Here in the rust belt northeast, I put anti-seize on everything. If you get a bolt loose the first time you count yourself lucky and hedge your bets for the future.