Author Topic: Rear wheels wont turn!  (Read 6026 times)

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Offline jjbunn

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Re: Rear wheels wont turn!
« Reply #15 on: Saturday,April 01, 2017, 12:38:33 PM »
The orange ring is an oli seal and I aasume that the steel ring inside it is the inner ring of the hub bearing. The spacer is the same OD as that bearing inner ring.
It looks to me as though your stub axle is too far inside that bearing, because I think the plain portion of the stub axle, i.e. inboard of the splines, should protrude from the bearing. The spacer sits between the hub and the bearing inner. I'm not sure of the dimensions, but it is usually recommended that they be hardened and since you can buy them from regular suppliers I don't know why you'd make them.
I mentioned earlier about using Loctite 35 or modern equivalent on the splines. I see that's only mentioned in the TC manual, but I'm pretty sure it's recommended for earlier cars too. Maybe someone could comment?

I think they are $30 a piece from Dent, so making them seems an economical alternative. But if they need to be hardened steel, that might be a problem.

Yes, I was using the correct Loctite on the splines, but didn't need any heat to break them free with the three prong puller.

If the stub axle is too far inside the bearing, why might that be? And how can I fix it? Somehow by pushing the bearing assembly towards the gearbox?

Thanks again!

Offline jjbunn

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Re: Rear wheels wont turn!
« Reply #16 on: Saturday,April 01, 2017, 02:55:56 PM »
This is from Tim Engels in the knowledgebase regarding the spacers:

Quote

X046D0148Z
2.125" +/- .010 long.
All models from the S1 up to but excluding the Twin Cam Special.

X074D0215Z
2.000" +/- .005 long
Twin Cam Special only.

The outer spacer is
0.375" long

All three OEM spacers are basically 1.5 OD / 1.25" ID steel tube parted off
to length and used as is... no heat treating.
1.500" OD (can be much larger
0.125" Wall
1.250" ID
It's a sloppy fit over the shaft and a more snug slip fit would be better.
(Shaft Journal OD = 30mm = 1.181 inch)

The ends of all spacers must be parted square and true

The inner spacers would be easier to center if they had a smaller ID that
was more of a slip fit on the shaft journal. The stock ID is just a
function of using common, off the shelf, thick wall tubing and parting it
off, and not a critical "right" fit. If I were making my own spacers,
I'd be inclined to spend a bit more on materials and machining and go for a
smaller ID and better fit on the shaft.

And the OD could be larger since there's nothing surrounding it. But
anything larger than the contact face of the bearing's inner race would just
be dead weight.

To keep the spacer from crushing under load and relaxing the clamp force
created by torquing the hub nut, the stress in the spacer must be kept
below it's compressive strength limits. That can be done by hardening the
spacer to raise it's limits, going to a higher strength alloy to raise the
limits, or thickening the wall to increase the cross-sectional area to
reduce the stress. Of course, thicker is heavier and not in keeping with
Chapman philosophy..Chapman philosophy..<WBR>. but not a

OEM spacers were nothing fancy and did have a tendancy to crush under load.
They could benefit from hardening. A better alloy steel would also help.
4130 or 4140 hardened would be an improvement. The best material would be
the same as used in the bearing race, but that would be overkill for the
job.

Later,
Tim

Offline jbcollier

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Re: Rear wheels wont turn!
« Reply #17 on: Saturday,April 01, 2017, 05:49:13 PM »
Strip the rear axle down and make sure the missing spacer isn't inside.

Offline Roger

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Re: Rear wheels wont turn!
« Reply #18 on: Saturday,April 01, 2017, 07:13:14 PM »
Well, Tim knows his stuff so you can make the spacers if you like.
The amount by which the stub axle protrudes from the upright is determined by how far it's pushed in. The inner bearing is relatively free to float in the upright, until the assembly of hub, spacer, outer bearing, spacer and inner bearing is tightened up. Even then, it's not located along the axis of the stub axle, that is done by the outer bearing.
If you have a bit of tube long enough to slip over the splines, try tightening with the hub nut and see if you can pull the stub axle out a bit.

Offline Certified Lotus

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Re: Rear wheels wont turn!
« Reply #19 on: Sunday,April 02, 2017, 06:07:30 AM »
Here are some photos of my tear down on my 72 TC. You can clearly see the spacer.

Offline jjbunn

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Re: Rear wheels wont turn!
« Reply #20 on: Sunday,April 02, 2017, 12:18:51 PM »
The photos are really helpful - thanks! Do you have a photo with the outer bearing removed, by chance?

I'm coming to the conclusion that I have the outer spacer, but it's pushed into the upright.

Offline BDA

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Re: Rear wheels wont turn!
« Reply #21 on: Sunday,April 02, 2017, 01:35:12 PM »
If I understand you, I don't think that could happen. There is a spacer between the two bearings in the housing and the outer spacer is running on the inner race of the outer bearing. If the outer spacer was pushed into the upright, it would have to do serious damage to the outer bearing.

Offline Certified Lotus

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Re: Rear wheels wont turn!
« Reply #22 on: Sunday,April 02, 2017, 02:06:52 PM »
I was just thinking the same as BDA. It's not possible for the spacer to get pushed past the bearing unless the bearing is destroyed. And then you have the larger spacer between the two bearings. There is no way for the spacer to move into the bearing carrier.

Offline jjbunn

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Re: Rear wheels wont turn!
« Reply #23 on: Sunday,April 02, 2017, 04:31:10 PM »
OK, yes that makes sense. The inescapable conclusion is that I'm missing the outer bearing  :-\

I've ordered some steel 1.5" OD 1.25" ID stock tubing, so will try to first make a sleeve with that to go over the splines and allow me to tighten with the hub nut against the bearing, as Roger suggested. I'm hoping that this will push the stub axle out a little, giving more room for the outer bearing, which I can also fabricate from the stock tubing.

That's the plan, anyway!

Offline andy harwood

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Re: Rear wheels wont turn!
« Reply #24 on: Sunday,April 02, 2017, 05:35:35 PM »
FWIW, VW Beetle spacers can be used, already hardened. A lathe or careful grinding gets them to size. (On a TCS)
« Last Edit: Sunday,April 02, 2017, 05:48:33 PM by andy harwood »

Offline BDA

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Re: Rear wheels wont turn!
« Reply #25 on: Sunday,April 02, 2017, 05:42:33 PM »
I would stick with a hardened spacer rather than plain steel tubing.

Offline Roger

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Re: Rear wheels wont turn!
« Reply #26 on: Monday,April 03, 2017, 05:11:14 AM »
I would stick with a hardened spacer rather than plain steel tubing.

I agree! And I think you need to review your use of Loctite. The stuff you put on the splines when you finally assemble the whole is type 650 from memory, and you certainly need heat to get the hub off after it's set.

Offline jbcollier

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Re: Rear wheels wont turn!
« Reply #27 on: Monday,April 03, 2017, 06:30:51 AM »
1/8" wall tubing is not going to make a spacer that can hold up under 150 ft/lbs of torque.

I would again recommend taking the upright completely apart to make sure nothing else is amiss.

The proper loctite to use is 635.  It is slow setting so you have ample time to assemble things before it sets.


Offline Roger

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Re: Rear wheels wont turn!
« Reply #28 on: Monday,April 03, 2017, 07:29:06 AM »
635, that's  what I  meant. Thanks jb.

Offline jjbunn

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Re: Rear wheels wont turn!
« Reply #29 on: Monday,April 03, 2017, 03:50:51 PM »
1/8" wall tubing is not going to make a spacer that can hold up under 150 ft/lbs of torque.

I would again recommend taking the upright completely apart to make sure nothing else is amiss.

The proper loctite to use is 635.  It is slow setting so you have ample time to assemble things before it sets.

But 1/8" wall tubing is what the factory used, no?