Thread: Semi Liquid grease or oil in a Series swivel hub ?

Great post Gromit. I'll be very interested in any discussion. I'm continually battling swivel leaks on my 86".

I don't think that the change to liquid grease had anything to do with CV joints. After all, the change was some time in the 90s. By that time, Rover had been filling Rangerover swivels with oil for their CVs for over twenty years. CVs were introduced on Series Landrovers with the Stage 1 in 1979, and continued to use oil in the swivels of 90/110 well after the Defender name change.

My 110, with over 600,000km and at 32 years, still has the original CVs, and they have always lived on oil.

As far as I can work out, the change was purely to prevent leaks and reduce warranty costs as customers and authorities started to be more concerned about leaks.

Most CV joints on other vehicles I've worked on in the past have been smothered in a molybdenum disulphide grease.
So....... did Land Rover change to grease with molybdenum disulphide to extend the life of the CV's but had to use semi-fluid type to get the top bearing lubricated ? Or did they use it to stop leaks under the warranty period ? As none of mine leak I'm not 100% sure about that idea
My defender had it added at some point in it's life. It's a 1995 model, there are no leaks (original seals) and as it's transferred into the diff I've just topped up with EP75W90.

The question is......does the semi-liquid grease lubricate the UJ's in a Series front axle because there seems to be a trend towards using it in Series Land Rovers nowadays.

Put together properly with a good swivel surface and a new seal there's no reason it should leak so should you just add molybdenum disulphide to the oil for a vehicle equipped with CV's and just oil for a Series vehicle (except Stage 1)



Colin

As I pointed out earlier, the MoS2 is quite clearly not needed for CVs, as shown by both Rover's use of oil with CVs for more than twenty years, and my own experience over 600,000km.

It is used in packed CVs simply to try and overcome the shortcoming of grease - grease pushes out of the way, and stays where it is pushed. Adding MoS2 to the grease means that a tougher lubricating film is left on the working surfaces.

While I have no experience with the use of the liquid grease in Series swivels, I can see no good reason why it would not be just as good for lubricating the universals as it is for lubricating CVs. While the universal probably clears a space for itself in the grease while travelling at speed, when the vehicle is stopped or moving slowly the liquid grease will flow back over the universal and refill at least half the bearing cups with lubricant. And when spinning, the centrifugal force keeps the lubricant in the cups. The only dow side I can see is if free wheel hubs are fitted and left unlocked for long periods, the cup at the top could eventually drain of all lubricant.

Originally Posted by JDNSW

As I pointed out earlier, the MoS2 is quite clearly not needed for CVs, as shown by both Rover's use of oil with CVs for more than twenty years, and my own experience over 600,000km.

It is used in packed CVs simply to try and overcome the shortcoming of grease - grease pushes out of the way, and stays where it is pushed. Adding MoS2 to the grease means that a tougher lubricating film is left on the working surfaces.
So I wonder why the LR semi liquid grease has MoS2 in it ?

While I have no experience with the use of the liquid grease in Series swivels, I can see no good reason why it would not be just as good for lubricating the universals as it is for lubricating CVs. While the universal probably clears a space for itself in the grease while travelling at speed, when the vehicle is stopped or moving slowly the liquid grease will flow back over the universal and refill at least half the bearing cups with lubricant. And when spinning, the centrifugal force keeps the lubricant in the cups. The only dow side I can see is if free wheel hubs are fitted and left unlocked for long periods, the cup at the top could eventually drain of all lubricant.
There is still the problem of using a UJ designed for a tailshaft where the seals stop lubricant getting in, the only access is via the grease nipple hole. I suppose it will rely on the grease already installed as it does in a tailshaft. I'll have to drop into Spicers at some point and see if you can get one without the seals, removing the seals let the needles float as mentioned before.

Personally I'll stick with oil it was just interesting note the trend towards semi-liquid grease for all applications and the comments in the link in the first post.


Colin

The MoS2 is probably added to provide temporary lubrication for the top half of the CV when the vehicle has been standing long enough for the semi-liquid grease to drain off, and when it starts driving it will take a while to get into that top half, especially in cold weather. Possibly also to provide the equivalent of EP lubricant - the additives used in EP oils may not be stable in a grease. From memory, a grease is effectively oil plus a thickener, usually something close to a soap. I'm not sure what is used as a thickener in this so-called liquid grease.

The problem of U-joints with seals versus unsealed ones is a separate issue, and I don't think is related to oil vs liquid grease. You used to be able to get the ones without the seals, but I don't think I have seen a new one for many years. Whether removing the seals is an issue will depend on the detail construction of the joint, and I have seen several different arrangements, not that I have ever needed to replace one. I think that if you installed one of the ones that are "permanently" lubricated, I would expect it to last indefinitely in a swivel. After all, the only reason they fail on tailshafts is if the seals are damaged or they get water in them because the seal leaked. Neither are likely to happen inside a swivel, as long as the oil (or liquid grease) is properly maintained.

Originally Posted by JDNSW

From memory, a grease is effectively oil plus a thickener, usually something close to a soap. I'm not sure what is used as a thickener in this so-called liquid grease.

Spoke with a colleague who works for an oil blender and he claimed you could just buy MoS2 grease, add oil slowly & stir and eventually you will get semi liquid grease.

Just read an article from Penrite and their semi-liquid grease has a shelf life of 2 years. I wonder how that impacts on its long term use......... Greases - What is an average shelf life of Grease? | Penrite Oil

Anyway, interesting discussion but as mentioned before I'll stick with EP75W90.



Colin

Having done quite a bit of research on Moly now - the advantage of moly is inherit in its chemical structure - in a nut shell, its attracted to metal, and its structure reduces friction between moving metal parts - and this reduces wear on the metal parts as a result. It is also superior to most metals and oils in high pressure / high temp situations - it is used to replace tungsten in tooling, used as armour plate, used in cannon barrels and as a coating on precision ammunition.

In ww2, it was used by the germans as an engine oil additive in their fighter planes - if the engine lost oil, it would continue to operate thanks to the moly coating on the moving parts.

What this means to the average landy is subjective I suppose - but the science on Moly - which is still evolving today - is quite compelling.