Copper grease on wheel stud threads

[jagnut66]

Hi,
Whilst renovating the rear end of the MG I took the rear wheels off to re-black the drums (they show through the Rostyles), the first thing that worried me was the fact that the wheel nuts were a bit loose, then to my horror I discovered they had all been smeared with copper grease by the previous owner!
Now I'm a big fan of the generous use of copper grease on threads but I was always told that wheel studs should be clean / clear of oils and grease, for precisely this reason, that it causes the nuts to work loose under load.
So, I'm posting this as a warning to any newer members on here that may be tempted to grease their wheels studs or wheel nuts, don't do it.
I always wipe Abby's wheel stud threads off before I replace the wheels and if there's any sign of oil etc. I give them a clean with thinners.
Simply from a safety point it's not worth it.
I hope there's no Moggies out there with grease on their studs.......
Best wishes,
Mike.

[alanworland]

Sorry to about your wheelnuts working loose!
My experience of lubed threads is the opposite, I have always have lubed threads! (never used coppaslip though). Usually give the male threads a stroke of my waxoyl brush, not every time, but frequent enough to prevent the threads from being dry.
This I have done all my motoring life (45 years!) on all the vehicles we have owned during this time and can honestly say I have never known wheelnuts come loose.
Strange!

Alan

[MikeNash]

Well, Mr Jagnut, I'm astonished.
I've greased my wheel nuts on all my bikes and cars for the last 56 years and had no trouble - except for a VW Touran which specifically stated that they should not be greased. And in recent years, probably the last 25, I've used a copper loaded grease. I did once have a wheel come off but then found that all wheel nuts had very bad threads, and then I remembered that the previous owner, my old uncle, had tyres replaced at a local garage who - guess what - had used air driven tools to tighten them. A change of wheel nuts cured that!
I'll be very interested in other owners views and any good engineering guidance in this matter. Regards, MikeN.

[les]

Well I don't believe threads should be bone dry, maybe not covered in grease etc but certainly to give a degree of lube, a dry thread can pick up and seize. I tend to dab the studs here and there with a bit of grease. In fact on my modern, well its hardly that really, the manufacturer specify a particular grease. I'd call it good engineering to keep threads running smoothly.

[bmcecosse]

I wouldn't use the copper slip - but yes a wipe with oil and also round the hub centre if it positions/locates the wheel. And then torque the nuts up correctly and all should be well. You not interested in my uprated rear dampers for your MGB ??? See Sales section - bargain price !!

[Trickydicky]

Hi Mike, do you know if they were torqued up previously before you removed them? That may explain why they were loose?

[beero]

I have always use a smear of copper grease for years ever since having series 2 Landys whose wheel nuts would seize and pull the studs out of the hub if not oiled. I have never had a problem with any vehicle.

[MikeNash]

Well, Mr Tricky,

I don't think the nuts on my wheels have ever been torqued correctly, certainly not by professional tyre changers. I suspect they just drove the nuts on until they were "right and tight". Fortunately the original the threads on the nuts were softer than those on the studs so I only needed to replace the nuts. However, can anyone give me the correct wheel nut torque? And the figure's provenance? To date I've just pulled them up till they seemed "right" - and its worked!

A quick trawl on the interweb shows this discussion is an old one and that the world is divided on the matter. But its important, if only on the great difficulty one can have in getting wheels undone on modern cars (and then off even when they're undone) at the roadside. I've always done it first in my yard where its sometimes required me to jump, not just stand, on a long bar and then use a heavy mallet to drive the wheel off. And then on assembly I've used grease on the threads (except on Tourans!) and between the wheel and the flange it butts up against.

On Moggies its simple - and I'd like to keep it that way! MikeN.

[LouiseM]

However, can anyone give me the correct wheel nut torque? And the figure's provenance?

The workshop manual states: Torque spanner readings - Road wheel nuts 37 to 39 lb.ft

[Trickydicky]

Well Mr Mike, the reason I asked regarding torquing up the wheel nuts is because it's as easy to forget to tighten up your nuts as it is to over tighten them plus not everyone does use a torque wrench as you say.
We can offer our opinions regarding should I shouldn't I grease the studs but if there not tight in the first place then they will come loose.
I am sure everyone has senior moments once in a while

[jagnut66]

Hi Mike, do you know if they were torqued up previously before you removed them? That may explain why they were loose?

Hi,
They were last torqued up by the garage that fitted new tyres on my wheels soon after I bought it. However, as I was watching them, I know they didn't put any grease on the studs.
This has provoked an interesting discussion with far more responses than I expected, as I said, I was always told to keep them clean and free of grease, so to see you all stating the opposite is quite a surprise.
I have to say I would still fight shy of greasing them but I can understand your point about the possibility of them seizing, so I will take all this into consideration.
The rears are now re-torqued and tight, something I check every time I replace a wheel.
Though I may slacken the rears off at some point again soon, just to check they are not seizing, though I've not had a wheel stud / nut seize yet, I suppose there is always a first time......
Best wishes,
Mike.

[The vast minority]

Going into the very basics.........I could talk for hours about torque

I can explain a bit about this as I was until very recently working as applications engineer in the field of automotive fastener design and specification to OEM's. I designed joints in everything from engines to rear view mirrors for virtually every tier 1 manufacturer and automotive constructor in business. Almost all joints that get specified are specified dry, in wet areas where the joint will see oil ingress on re-assembly a reduced torque figure is used and a lubrication would be specified.

What everyone overlooks is this, torque is simply your mechanism for generating clamp-load, don't get wrapped up in torque alone. People do so because they can measure and apply a given torque but this is a very small part of what's actually going on in a threaded joint and by no means the most important factor. It is in fact, the least important, it's specified because at the specified level, it generates a known clamp-load. You cannot measure this, and so you must measure torque, I'll try to make this simple........

the relationship between torque and clamp-load is drastically altered by lubrication.
If you torque a nut or bolt, dry to a given figure it will apply a known clamp-load depending on materials of construction and any surface coatings present.

If you the lubricate that same joint and apply the same torque you can actually double the clamp-load, this can be destructive in things like soft aluminium alloys for example and is the primary reason for threads to be stripped from hole and or stud. This of course applies to steels, plastics, anything in fact that bears a thread.

Why? Because by lubricating you are dramatically reducing surface friction, this surface friction was taken into consideration at the design stage and by eliminating/reducing, you cannot expect to be able to use the given torque figure and expect the joint to perform as intended.the clamp-load will be far higher than required which will cause its own problems.

It is acceptable to grease a nut or bolt that was designed for dry assembly but once you do this, you may as well throw away your torque wrench because you are applying massively more clamp-load than the designer intended. You are also, in the case of vibrating nuts or bolts increasing the possibility of dynamic load losses, this Is because a threaded joint is much more mechanically stable dry. If it's lubricated it will work loose at the designed clamp-load, by applying the designed torque to a lubricated nut/bolt you reduce the posibillity of the joint working loose through dynamic loading by putting way too much stress on the thread flank to overcome the lubrication and finish up at the designed torque.

Basically, lubricate if you want but if you do, you must not use the advised torque figures for assembly as you are creating yourself potentially very dangerous clamp-loads on threads not designed to take it.


Al

[johngrigg]

Al
Thanks for that very clear and useful explanation which bears out what I was told by an ancient mechanic many years ago, that is if the thread is working in oil like a main bearing bolt lubricate it. If not, like a head stud or a wheel stud don't.
JohnG

[MikeNash]

Thank you Louise.
So with lubricated studs I must use a figure well below 37-39 lb.ft. I'll go see with my torque spanner what I've put on! Anyone going to give a guess of what to use for a lubricated stud? What about two-thirds of that, say, 25 lb.ft?
Regards, MikeN.

[les]

There's always something to worry about isn't there!

[smithskids]

I have always used copperslip on the wheel studs or bolts but not on the contact faces, no problems so far in the last 50 or so years

[MikeNash]

A quick check with my old fashioned "bending beam" torque wrench shows 20 to 25 lb.ft to start the nuts undoing and about 30 to do them up again. Of course the scale is close and not easy to read but that seems about right to me based more on "feel" and the principle of pull 'em up with short spanner and undo 'em with a large one. Am I about right with my figures? Anyway, the wheels don't fall off! MikeN.

[sid]

as a lorry driver,we've been plagued over the years with our wheel nuts coming loose.nowadays most trucks have the yellow markers on the studs,so you can keep a check on any loose nuts..though i don't think they'd look very attractive on a classic car!

[drivewasher]

I have a newsletter from VOSA somewhere in our garage. We used to get regular bulletins from them as we operate PSV busses.

The letter say to remember that wheel stud or bolt threads MUST NOT BE greased or lubricated. The only exception is if nuts/bolts are very dry rusty/squeaky just a matchstick head sized drop of OIL NOT GREASE should be applied to..... I can't recall, but think it was to the nut/female thread. Just to aid fitting. The reason given was you can't apply the correct clamping torque when threads are lubed.

They say that they have found in 95% of attendance to a lost wheel was found to have recently had the threads lubricated.

In our tyre bay we try and remove grease etc with brake cleaner before putting wheel back on a customers car. We always add an advisory to the invoice that wheel nuts had been greased previously

[philthehill]

How did we survive in the days when common sense was all we had to go on.
I have worked on plenty of commercial vehicles and engineering plant over the years and some big stuff at that and all we had to use was a great big wheel wrench or at best a 1" drive socket and 'T' bar with a piece of scaffolding pipe to get the b--g-rs undone.
I cannot remember ever seeing or being given a torque figure for commercial wheel nuts and I never had one come undone or adrift.
Wheel nuts should be checked regularly for tightness - In fact the Morris Minor workshop manual states that the wheel nuts should be checked for tightness every 1000 miles. Does any one do that?
And yes I do use a slight smear of 'Copper Ease' on the wheel nut/studs threads of my moderns and trailers and I have never had a problem with loose nuts because they are regularly checked for tightness/torque.
So if I present my modern for MOT and there is grease on the threads of the wheel nuts/stud threads will it fail?