I think Ian should indicate that it is his personal opinion not to use an EP oil in the rear axle. There has been considerable discussion on this topic in the past (search EP140 and see the blogs in August 2010)
It would appear that in the early days the presence of sulphur in these oils was a concern re attack on bronze etc, but not by the late 30's. No one has yet offered pictures of seriously corroded bushes in recent times. Anyone out there with a sad story to tell?
In the later Austin handbooks, and "most recently" in their publication 2230 I, dated September 1950, Austins specify an EP140 oil for the rear axle of The Seven.
This is what I have used for over forty years with no adverse effects.
Ron

Location: Thornbury South Glos

Opinions also differ on the steering box. Some say that grease gets away from the working surfaces and, unlike oil, doesn't get brought back by gravity. Grease can also work its way up the steering column to land in your lap, although that's never happened to me. On the other hand oil will tend to leak out of the box, so needs reasonably regular attention. So I go for the worst of both worlds and create a "groil" out of grease and thick oil. Hasn't caused me any problems thus far.

Currently I use EP140 in the back axle. When I run out I may well change to the older type of 140 grade - can't do any harm I guess?

Geoffrey

Penrite do a "steering box lube SBL00045" which is a fluid grease. I have just installed it so no experience so far except to say careful when loading the grease gun! It slops unexpectantly. I'm allways careful with grease guns and I allways get sh*t all over the place! cheers Russell

Location: OZ

Ron,

I beg to differ that-

"I think Ian should indicate that it is his personal opinion not to use an EP oil in the rear axle. There has been considerable discussion on this topic in the past (search EP140 and see the blogs in August 2010)"

Many writers on the subject still indicate that most EP oils are not needed or even suggested for early vehicles, including Austin 7 rear axles.

I won't go through the story again lest Bill points out that we do this regularly, but anyone who really wants to understand the story of lubricating Austin 7's (as well as others) should get a copy of 'Which Oil' by Richard Michell. This explains exactly why you should use a GL3 gear oil in the differential of an Austin 7 and also notes that when the Austin 7 gearbox specifies engine oil this does not mean use multigrade engine oil.

Where you say -

"In the later Austin handbooks, and "most recently" in their publication 2230 I, dated September 1950, Austins specify an EP140 oil for the rear axle of The Seven."

when this was written I think that the EP referred to was to GL3 antiwear specification for spiral bevels with rolling contact - the Austin 7 differential. GL4 was developed for the early hypoid gears with sliding contact, leading to GL5 and so on.

"This is what I have used for over forty years with no adverse effects."

You would have originally been using EP gear oil to GL3 - are you still?

Please read the book 'Which Oil'

Tony.

Location: Malvern, Melbourne, Australia.

If you go to Millers Oils web site and ask a technical questions you will get an emailed reply that says 'UNDER NO CIRCUMSTANCES' (their capitals) should their EP oils be used in axles (and gearboxes) that have any bronze components.

Been there, done that in a different context.

Steve

Location: Nr. Selby, North Yorkshire

Oh dear.

I've used EP140 in the axle and general purpose grease in the steering box for 40 years and at least a quarter of a million miles.

Must have b*ggered it completely by now.

Location: Herefordshire (with an "E", not a "T"!)

Me Too.

EP140 Hypress , however ,NOT EP 140 Hypoid.

Location: Wessex

Well, it may be boring but, I tend to follow oil company's advice. If they say that they DON'T recommend one of their products for a particular application that carries more weight with me than when they DO recommend a particular product.

There may well be people, somewhere in the world, who have used nothing but margarine in the diff. for the last 60 years without ill effects but, I think I'll just keep on following the supposed experts in the industry's advice. After all, why would they lie?? They end up selling me one of their products anyway and the price difference is insignificant.

Ian Mc.

Location: Shropshire

I think the snag with margarine,Ruairidh, at least in the western world, it hasn't been available for human consumption for some years.
When butter was in very short supply in WW2, margarine was produced as a healthier (and more available) option. Today, however, it has been seen fit to ban it!! Cela vie.

Ian Mc.

Location: Shropshire

Ian,

In the Principality of Glasgow we eat many things the rest of the world sees unfit for human consumption...

I again hesitate to insert any technical information into a discussion centered around always using the same oil for 40 years but-

EP 140 Hypress is a high viscosity SAE 140 (Society of Automotive Engineers) API (American Petroleum Institite) GL4 gear oil which has about 50% of the additive (including Sulphur) of a GL5 gear oil. GL4 rating is for spiral bevels (Austin 7's) and hypoid gears in moderate service.

Now this lower level of additive may not cause any great damage to the bushes in the Austin 7 differential but the GL4 rating is not needed for the Austin 7 gears - GL3 (which still includes a mild EP additive) is adequate.

At the low sulphur level it would probably take some time to damage the bushes anyway.

I don't know the GL rating of margerine

Tony.

Location: Malvern, Melbourne, Australia.

Back in 1923, the official spec was probably on the lines of "fill it with something thick and slimy"!

Location: Herefordshire (with an "E", not a "T"!)

Pretty much- a mixture of half and half engine oil and Stauffer (later yellow) grease, no quantity specified but it was suggested add more every 1,200-1,500 miles or monthly.

A less likely lubricant would be hard to find and the excess probably stopped the rear brake drums from rusting

Tony.

Location: Malvern, Melbourne, Australia.

Thanks Tony for your input and thanks also to Frank. I have been prompted to have another good look at the August 2010 discussion and dig out some of my old company handouts - a useful re-cap.
I can confirm that for years I have used Castrol Hypress gear oil which is one of the ones specified in the 1950 Austin Handbook I referred to earlier. This is an EP SAE 140 oil and, as Tony suggests would have been a GL-3 spec. There is a suggestion that it is now to a GL-4 spec and it would be good to have this confirmed, if this is the case. I have an un-opened small container of Castrol Classic and this is marked EP GL-4. I shall probably use this next unless someone can tell me where I can get a GL-3 oil.
Extreme Pressure additives are there to ensure that lubrication is maintained even if the oil film momentarily breaks down. My handbook by Dr Summers Smith summarise with ......."Most industrial gears run perfectly satisfactorily with straight mineral oils, though e.p. oils may give some benefit with gears subject to shock loading".
So there you have it! Use a straight oil if you don't think there will be any serious shock loading; but... I rather think that with A7 clutches, and the general way we treat our cars, shock loadings are pretty plentiful! Add to that the impact between the gears on a "noisy" axle and I'm for an EP oil.
The point has been well made that it must not be a Hypoid (GL-5)oil due to the serious effect this much higher concentration of additive will have on any "yellow metal".
Taking on board the comment from Miller Oils, perhaps the strength of the additives in the EP oil they offer puts it in the category of a GL-5 spec.
Ron

Location: Thornbury South Glos

Ron,

The sulphur phosphorous EP additive in GL 5 and even GL 4 lubricants only becomes active under extreme sliding conditions such as in hypoid gears - with rolling tooth contact in the Austin 7 spiral gears there is no need for anything other than viscosity - straight SAE 140 does the trick and is highly unlikely to 'break down' in the Austin 7 diff.

If the early cars survived on a 50/50 mix of engine oil and yellow grease they should last forever on 140 gear oil

Tony.

Location: Malvern, Melbourne, Australia.

Tony,
Whereas EP oils are essential for hypoid gears, they also have an important duty in other situations where the gears are in contact under extreme pressure - hence the oil's description.
There is a contrast between the steady state rolling tooth contact within a gearbox in an industrial application and the complex dynamic loading that goes on in a rear axle. Any axial movement of the pinion plus flexing within the carrier bearings will produce small amounts of shear; but the big unknown, in terms of pressure, is the effect of impact. Even in a correctly set up axle, vibration through the driving train "finishes up" at the axle (the wheels are big dampers!) where it can add an impact load to the driven load. Wear, poor assembly, nearly running out of oil and a harsh clutch add considerably to the need for something better than a straight oil - and then there's the way we treat our cars/specials.
I think these are some of the underlying reasons why Austins specified Hypress EP 140, or equivalent. This is what I shall continue to use, and I shan't lose any sleep over attacks on yellow metal.
Ron

Location: Thornbury South Glos

Ron,

At the risk of boring everyone - Industrial applications notwithstanding- the GL4 EP sulpher phosphorous additives give minimal advantage in spiral bevels where there is no continuous sliding contact under pressure, just, as you, indicate shock loads which need high viscosity - hence SAE 140.

Obviously you can of course do as you say.

Before someone else says - I will stop pontificating and shut up.

Tony.

Location: Malvern, Melbourne, Australia.