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ROTOFLEX HUB NUT


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You may recall from previous posts that last summer removed rear hubs to fit longer /stronger wheels studs. 

To cut a long story short  now we are getting about a bit , offside hub nut keeps  coming loose within 100 miles. Always thought nyloc engagement was poor / non existent but is same on both sides .

Nuts were replaced new from Paddocks and tightened to 145 nm . Have now tried to get 'genuine ' nuts from Mick dolphin but he sold last ones recently.

I marked nut and shaft when rebuilt last summer and its returning to original position so don't think anything has collapsed / moved and there was no indication of a loose nut when hub remover last summer . 

Thin nylocs are available but with high tightening torque not sure sufficient threads engaged. Also cannot find a UNF stake nut either

Anybody know correct nut spec and who sells em 

In absence of anything else will try Loctite threadlocker .

any thoughts o wise ones ?

Paul

 

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All the usual suspects list nyloc nut against oe p no 510618. but is it the correct part . it is an engineering issued number as opposed to a standard generic hardware part number from the Triumph hardware catalogue.

Grimmers show  510618A , where A suffix indicates alternative as far as I know. I only buy from them if I really really have to. Too many bad experiences I'm afraid.

Canleys are usually very helpful I,ll ring them for a height dimension and compare that with what I have got.

145 Nm is mid tol torque 112.5 lbft

 

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I always thought the correct spec nylon was not particularly well located as the threads aren't fully formed to the end of the shaft. Couple that with 50 yrs old shafts and worn threads is not ideal. I've got a vague memory that Jaguar spec the same spec nut for one of the classic Jags - XK120 ?

Gav

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Before I changed to CV shafts on my GT6 I bought a spare nyloc just in case I needed it after a job I was planning to do. It came from either Canley or Paddocks and was a much deeper nut than the original. If I'd used it, I don't believe the nylon section would have engaged with the thread sufficiently to lock it, which sounds as if it could be the issue you are encountering.

My CV shafts with the original bearing design use a shaped nut that is peened into a channel to achieve locking.

Gully 

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Thanks Nick , interesting. Important to understand why something is happening before attempting to fix it. Initial investigation centred on suspect parts.

Could this have been compounded by the fact that the two times I have had the hub off I did not mark the splines and replaced in a diferent orientation.

 

Pete found stake nuts online but no evidence to say they are unf . Thanks for looking anyway , 

CDD CV shafts use a stake nut but do not advertise spares.

 

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29 minutes ago, griffipaul said:

Thanks Nick , interesting. Important to understand why something is happening before attempting to fix it. Initial investigation centred on suspect parts.

Could this have been compounded by the fact that the two times I have had the hub off I did not mark the splines and replaced in a diferent orientation.

 

Pete found stake nuts online but no evidence to say they are unf . Thanks for looking anyway , 

CDD CV shafts use a stake nut but do not advertise spares.

 

I have the CV shafts conversion. The staked hub nuts are different size and, I think, metric thread to fit CV shaft, so not compatible.

Gav

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5 hours ago, griffipaul said:

Could this have been compounded by the fact that the two times I have had the hub off I did not mark the splines and replaced in a diferent orientation.

Don't think so.  It's quite difficult to tell if there is play as with the hub fully home, it's inner end is (or should be) an interference fit on the unsplined shoulder section of the shaft, so you won't feel any backlash, though you may get a pronounced click or clack from the offending corner when going from forward to reverse and vice versa.  To confuse matters they sometimes click without undoing your hub nut!  You can check the backlash with hub removed just enough to get it off the shoulder - use a bar across the stubs to get a bit more leverage, I don't think hand pressure on the hub diameter alone is enough.

The other thing to check which I should have mentioned before is that you have the correct thick, hardened washer under the nut?

 

Nick

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Washers were replaced new when I first did the roto couplings a few yrs back , will check paperwork to see where they came from , probably Paddocks , suspect they are ok but will check them out just to be sure. Hopefully will get some nut dimensions from Canleys when they open Tuesday and go from there either with new nuts or Loctite . Have a good run scheduled for next Sunday so that will test it . Will keep torque wrench handy and check regularly.

When i did the wheel studs this hub came off comparatively easy compared to the nearside , so perhaps splines are worn . New hubs are availlable but shafts are a bit more problematic in more ways than one.

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No sign of thread engagement with nyloc ring

thread length is approx 11.25 giving approx 8 threads ,

washer does not look to be hardened and can be filed shows  nut witness on one side and hub on other

have taken a punt on Canley nuts and washers.

P1040074.thumb.JPG.2c4f5e577da9f32e475dcc2d89ccac65.JPGP1040073.thumb.JPG.5b2e6b17d748da9ff178e5a1a38ef1b9.JPG

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Hmm. That nyloc looks to be the correct size with Mk 1 eyeball. Not good if nylon is not engaging with shaft threads at all! How do the threads look on the shaft ? On my old shafts the last two threads weren't fully formed - poss damaged by a BL chimp many years ago, before I got the car, during a donut / wheel bearing replacement!

Gav

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50 minutes ago, trigolf said:

Hmm. That nyloc looks to be the correct size with Mk 1 eyeball. Not good if nylon is not engaging with shaft threads at all! How do the threads look on the shaft ? On my old shafts the last two threads weren't fully formed - poss damaged by a BL chimp many years ago, before I got the car, during a donut / wheel bearing replacement!

Gav

As above, that nut appears correct to me also. It's essential that the nylon locking ring engages fully, and I'm puzzled why it wouldn't.

Nigel

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New nuts and washers arrived from Canley's , usual excellent service .

comparison photo below  , but detail is interesting.

washer thickness  existing = 4.98 , new Canleys = 3.8 , difference = 1.18

nut height existing = 14.47, new Canleys =14.0., difference = 0.47

but significant difference in nyloc position and depth by approx 1.5 mm

so with canley set up i have additional  3.15 thread protrusion into the nyloc.

as per my previous post I had considered really thin nylocs , but not sure that they would withstand torque applied

P1040075.thumb.JPG.9389e640e491e3c1accbba8ec59af5da.JPG

With existing I can screw nut all the way with no prevailing torque , but with new set up I can feel nyloc resistance well before grounding.

So I have torqued up new set up and see how we go Sunday.

But I suspect  the real issue is the shaft threads

, Can someone confirm that shafts should be threaded to the end because both of mine are not . So I did not suspect anything wrong. I always wondered why the WSM said to protect the threads when removing hub , cos i dont have any on the end to damage 

I therefore suspect that over the yrs previous work has resulted in thread damage and they have  been cleaned up to allow nut fitment and compromised the thread engagement.

Can anybody confirm my suspicions

below is previous photo I have of other side which is in similar condition but holds torque and as best I can get on the problem side without taking wheel off

20200806_131006.thumb.jpg.481ae84989f1bf8e479746b45ccee598.jpg20210505_113846.thumb.jpg.38ce7f1c30265d2e46ef8364ebcd8ff4.jpg

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2 hours ago, Gully said:

They do thin form nuts which may be appropriate.

Gully

Sorry, but thin form nuts are unlikely to withstand the torque required on the out axle shaft. It would be potentially dangerous to fit anything of a lesser speciation than the original part.

Nigel

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The short unthreaded section is normal for the rotoflex shafts.

Although the hubs are not as tight to remove off the outer driveshaft as the Swing axle shafts, I still had to use a proper hub puller when I rebuilt the rear suspension on my Mk2 Vitesse

The threaded section tends to get stripped or damaged if you use the nut to pull the hub onto the shaft, a mate who helped me rebuild mine used a suitable brass shaft to drift the hub on before we tighten up the nut?

It was a faff setting up the end-float of the bearings if I remember correctly too, you need the slightest 1 to 1.5 Thou max play or you will ruin the bearings, anymore and chances are the M.O.T. Tester will fail the car too.

Gary

  

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3 hours ago, Nigel Clark said:

Sorry, but thin form nuts are unlikely to withstand the torque required on the out axle shaft. It would be potentially dangerous to fit anything of a lesser speciation than the original part.

Nigel

Fair enough - was looking for a solution to an odd problem, but looks like the issue should be solved using the smaller Canley nut, with the problem being caused by the original nut (and washer) being oversize. The Spalding site does recommend talking to them about performance requirements and specifications before ordering, which is sound advice and a good service.

Gully

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