Rear Hubs

[carrierdave]

I have recently replaced one of my rear wheel hubs with a new (old) output shaft. I installed it with new bearings etc and a new Nyloc nut.
The problem I have is that the nut is relatively deep and the screw thread on the shaft does not take up in the end of the Nyloc.
When you look inside after removing the nut and washer there is about 2-3mm difference between the end /start of the thread on the shaft and the washer landing surface in the hub (if that makes sense).
I have read a couple of articles that state you need to 1). Bed it in with grinding paste, and 2). Heat the hub up to ? temperature and then bolt it up.

1. Will heating the hub up overcome this difference?
2. Do I need to get the shaft machined to suit the hub?

Any comment would be appreciated.

Dave

[alaric]

So, are you saying that you can't tighten the nut up because the shaft doesn't poke through the hub flange enough?

If so, that does sound similar to my rear hub in which I fitted a new shaft recently. I didn't have a nyloc nut - I think there were a couple of cuts in the end of the nut, that would cause it to lock onto the thread - it was a new nut with the shaft from Paul Matty's. The nut wasn't 'deep'.

I was able to tighten up the nut, but the wheel flange is still a few mm away from the hub - further than on the other side of the car. I haven't yet lapped the taper onto the output shaft - other priorities to get on with - and have assumed that this difference will close up when I do so.

I can't think of any other reason than that the wheel flange needs to be lapped to the new outboard drive shaft - sounds like there's a lot to take off in both cases if that's the cause. I was a bit concerned about making sure it was centred properly - one of the reasons I haven't touched it again yet.

I hadn't heard of the idea of using heat to help put the flange on again - I know people do that for removal. Maybe this will close up the gap. Don't want to make it too tight though - can they break - I don't know on this.

If anyone has any ideas on ensuring that the lapping process centres the wheel flange properly I'd be interested.

Is there a tolerance on the gap between the hub rim and the taper fit wheel flange?

Sean.

[brassringfarm]

I had a similar problem. Purchased half-height nylock nuts from Dave Bean. But I was nervous about there not being enough thread. I ran them for a year and all is fine so far. No racing though.
Paul Zimmerman
65 S2

[Emma-Knight]

Will they be fitted dry or slihgtly oiled?


I was about to fit k/o hubs on my S2 (to replace bolt on's).
Looking at one of the (original) k/o hubs, I found a shrinkhole
right at the driveshaft entry in the key cut-out, about 3mm long
and 1mm deep. Any opinions/experiences if this might cause it to crack?
Should I replace it?

Will I have managed before snow?

Anna

[carrierdave]

Sounds exactly like the same problem. You need to be very careful when doing up the nut; last one that was on there I over tightened and stripped the thread on the shaft ? hence the change over.

Has anyone drilled through the shaft to locate a small split pin? Obviously this would have to be marked with the hub on and then drilled with it off.

I?m not sure about the bedding/grinding in process and who much it will improve the situation. Also heating and expanding the hub to get it on will only increase the ultimate loading on the nut.

I?m sure there is someone out there who can help.

Dave

[marcfuller]

I would fit it dry and use locktite on the shaft taper.

Dave Bean's catalog has very good directions on fitting the rear hubs. It includes directions on where to grind/smooth to eliminate stress risers.

Keith also provided a detailed discussion in this forum on fitting rear hubs and fully covered the fretting and stress problems.

Lapping the hub to the driveshaft with valve grinding paste should be self centering. It helps to remove fretting from the shaft and and hub. This provides a sound base for locktite which will prevent future fretting, make for a better assembly and ease future disassembly.

[M100]

There are two (or is it three?) heights of nylocs. I'm reasonably sure the nuts used are the "thin" ones. Are you sure the keyway is not fouling the assembly? As mentioned above lap it to a good fit. Mine have survived without loctite. No desperate need to use it on the nut but it won't do any harm but definitely don't cross drill it!

Would someone like to scan and post the hub fitting recommendations in the Dave Bean catalogue? Previous requests have fallen on deaf ears. Better still scan the lot (I can assemble it into a pdf if required)

[marcfuller]

Previous requests have fallen on deaf ears.

Martin,

It is probably not so much a hearing disability, as it is respect for Dave Bean and the fact that the 150+ page DBE Elan Performance Manual and its related price list is in print and only $6.00. http://davebean.com/catalog.htm

To illustrate the value of that $6.00, here is a link to a pdf of the DBE Manual's instructions for the "Care & Feeding of Elan Stub Axles and Bearings". It includes the diagram for removing the stress risers. This is a good example of the type of unique information that makes DBE's Manual and Catalog so helpful.

[alaric]

Thanks for that sneaky look. I'll pay their website another visit.

Sean.

[marcfuller]

Move along now ... these are not the droids you are looking for.

[reb53]

Know exactly what you mean Dave.
The several times I've done mine over the years I've had to reduce the length of the Nyloc nut slightly to enable the nylon ring to do some actual locking. I wasn't aware there were different lengths which would be the answer. In my case I machined some off the end and I haven't had a wheel fall off yet!
In fact, seeing how hard it is to get the b**gers off when you want to, I'm not sure the nut is necessary!

Ralph.

[triumphelan]

It`s worth getting some "engineer's blue " this is spread very sparingly on one surface and then the mating surface inserted and gently rotated this will show where the mating surfaces are and how much contact area there is .From my apprentices days I think "8 spots per Square inch " was the rule of thumb

[fasterbyelan]

The earlier post regarding the cost of the David Bean Manual reminded me of the request I recently made to them for the price of it sent to the UK. I quote their reply-

Yes we can send them to the UK. The cost is $6.00 for the catalog and around $20.00 to $30.00 to ship it.

-Ouch!

Is the manual available in a PDF?

[rgh0]

Dave

The Lotus standard nut was a half height Nyloc. Apart from all the other advice given about lapping, blueing, removing stress raisers and using loctite when assembling one thing to be careful of is that the hub does not go on so far that the washer under the nut bottoms out on the shaft.

I normally back off the nut once I have first torqued it up to check how far the hub has gone on when it was torqued as the hub moves in a signficant distance and you cant judge how far this will be until it is properly torqued. If the washer bottoms out you can end up with the taper not properly locked and the hub can spin on the shaft.

Over time the orginal hubs tapers tend to grow and the hubs go on further and further with each fitting especially if you lap them in each time also. If you get to that point you can make up a stepped washer to still keep using the hub and shaft.

If you can get a full height nyloc on the end of the thread then you will be close to bottoming out on the shaft.

regards
Rohan

[M100]

It is probably not so much a hearing disability, as it is respect for Dave Bean and the fact that the 150+ page DBE Elan Performance Manual and its related price list is in print and only $6.00.

It always was the exhorbitant cost of postage, and the cost of the phone call that stopped me getting one. The simple task of putting their catalogue online might actually help their sales while reducing the environmental impact of printing and sending the catalogues. The "profit" in a $6 catalogue must be close to irrelevant in the grand scheme of things, it's hardly worth the administration costs. If they genuinely had something I really wanted and it wasn't available over here I wouldn't flinch at the extra cost of $6 for a catalogue on a delivery of parts, but $30 for postage (as I too was quoted only a few months ago) even for 150 pages is just taking the piss.

Don't forget that over this side of the pond someone scanned Mick Millers catalogue full of Elan "gems" and the early Lotus parts book with all the oem parts numbers is also available online (and shortly so will the early workshop manual that is no longer available from Lotus)