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Trev

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Joined: 15/07/2006
Location: Australia
Posts: 640

Posted: 10:26pm 23 Oct 2023

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That's true Phil. They should be in alignment. See the locator. This locator fits the rim. Both motors have this locator. and keeps the 2 motors in line.
Another picture from some time ago.

Trev @ drivebynature.com

Godoh
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Joined: 26/09/2020
Location: Australia
Posts: 458

Posted: 04:41am 24 Oct 2023

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Hi Trev. The stainless steel bolt may not be strong enough for the job.
They are not as high in tensile strength as High Tensile bolts.
I would suggest using 10.9 grade high tensile bolts instead.
Stainless bolts can also gall up and sieze in the thread section if they are not installed with anti sieze too.

pete

Murphy's friend

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Joined: 04/10/2019
Location: Australia
Posts: 651

Posted: 08:17am 24 Oct 2023

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Agree with Godoh, 316 stainless is not the best choice for this application. You can get crevice corrosion inside the hole the bolt goes through, I had bolts break on my boat for that reason.
If you must use stainless then 304 grade is a stronger choice but High tensile bolts would be best.

Trev

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Joined: 15/07/2006
Location: Australia
Posts: 640

Posted: 09:23am 24 Oct 2023

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Pete, I had found that chart a few days ago. And I did some calculations. But here I will type it out. My scrawl on the paper will be hard to follow.

There is 18 of those little M5 bolts. 316 Stainless steel. That's the factory bolts.
Cross section area of all 18 of them, 353mm2
353mm2 x 700N/mm2 = 247450Nm

The 5 stud bolts they have are M12, 10.9 high tensile.
Cross section area of all 5, 565mm2
565mm2 x 1035N/mm2 = 585355Nm

So you can see straight away that the small M5 bolt strength is not matched. However they do have leverage (greater circle diameter) compared to the the 5 stud bolts.

But with all the possibilities, still the question arises, why the left motor and not the right motor?

Wheel nuts are tapered. This helps to align but also stops the rim from slop on the stud bolts. I thought maybe if my Brake and auto friend and Pete suggested, hardened dowel pegs, maybe the bolts should be tapered. Countersink.

I have drilled and tapped to M6
calculating....
18 x M6 bolts cross section area, 509mm2. 316 stainless steel
509mm2 x 700mm = 2356303Nm
That is still not up to the 5 x M12 strength, but better than is was. I don't think I have enough room to drill and tap 8mm. And I am hoping that the extra leverage will make it enough not to break them.

Anti seize is not a good idea. I can't have them coming loose.

I have assembled the motor with the M6 countersink 316 stainless steel bolts and the suggested Locktite 515, as a sealing gasket and on the threads. I sure hope I can get it apart if need be, some time later. I have also added 3 threaded holes to use with jacking bolts to separate this plate off which should make future dismantle easier.

Thanks everyone for your ideas.

Trev @ drivebynature.com

Godoh
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Joined: 26/09/2020
Location: Australia
Posts: 458

Posted: 08:07pm 24 Oct 2023

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Good to hear that you are onto it Trev, I hope that it works out and there are no more failures. Happy travels
Pete

Trev

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Joined: 15/07/2006
Location: Australia
Posts: 640

Posted: 11:05pm 29 Oct 2023

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I checked all surfaces with dial indicator (as I have done before).

And lined up. To give some perspective, I see on the dial indicator differences the thickness of masking tape.

So.... . .... the only real change is the M6 Countersink bolts and the Locktite 515.
We will see if that fixes the problem.

T-Rev is all back together again and drove it to town (Mackay). All seems ok.

Trev @ drivebynature.com

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