RP Steering Box Oil Level

[JonE]

I note Penrite Transoil 250 blurb suggests it's a 600W Steam Cylinder oil, which is a lot cheaper... any comments from old steamers?

C Bennis replied: "it is known for some to use steam oil as it is a non EP oil (compounded steam oil contains tallow this would act similar to an EP additive). The closest you would get in steam oil to an SAE 250 is the 220 steam oil; the 460 is slightly thicker"

Elsewhere the tallow or rapeseed additive is said to make it similar to a gearoil. Does tallow addition make it bad for steering box internals?

[Hedd_Jones]

I've always used the table below as a useful reference in viscosity terms. I'm not so sure about the equivalents you quote Jon

I use the bearing oil that I use on my steamers, which is a ISO460 compounded with tallow in my Austin rear axles. 

Similarly I am happy to use straight (or up to GL4 - Non EP) SAE 140 gear oil in my bearings. These bearings are plain bronze. Rape compounding is also common, rape has a tendency to leave a residue on paint, and steamers run a total loss system, so it is less preferred by some (i.e me), but perfectly fine on yellow metals. 

The compounding in simple terms makes the oil 'sticky', so for a lub oil it stays in the bearing or on the shaft or face longer. Those who know more about oils than I do tell me this is desirable in a gear oil also. 

Obviously SAE220 gear oil is less viscous, i.e thinner. I wouldn't consider ISO460 or ISO220 a 'steam oil'. They are just lubricating oils.

Going more viscous to 'steam oil' so to ISO680 and ISO1000 gives you some real gloop. I use ISO1000 as cylinder lubricant on one of my steamers, ISO680 on the other. Again both compounded with Tallow. 

I use the 1000 in the clutch release bearing on the 3 speed cars, and having read the comments on here, I believe would be perfectly suitable for the steering box, as I guess would the ISO680, its just not as gloopy. But the ISO680 would probably be broadly equivalent to the SAE250 Penrite product quoted here.

In cost terms, I buy in 25l drums (remember - total loss system). But I'm paying broadly £7/litre delivered. I hold 460. 680 and 1000 generally in my Oil stores, plus Classic 20/50 engine oil.....  

A very clever man once gave me some very good advice. This is summarised thus - Any oil is better than no oil. The difference between the best oil for the application and a suitable oil for the application is so small its not worth worrying about.

My view is all the oil discussed here is suitable for steering boxes. I use grease!


  Oil viscosity chart.jpg (Size: 55.34 KB / Downloads: 158)

[Dave Mann]

After I rebuilt all my steering boxes they were filled with Castrol D140 with some molyslip after which one car decided to eject the stuff onto my trousers a problem I'd never experienced with grease lubrication in the previous 50 years. Before I could investigate further the steering box was replaced after an encounter with a BMW. Someone did say this was caused by excessive clearance between the worm shaft and the bush above the worm. I didn't investigate further because I scrapped the worm, worm wheel and drop arm so it didn't find it's way onto another car.

[Reckless Rat]

I use black graphite grease in the RP steering box on assembly. Not a lot, just enough to coat the worm and the gear wheel and the cover bush. Given the mileage I do, it never needs attention.

[David Stepney]

Still using SAE 140. A couple more blobs of grease appeared, and then nothing from the top of the column after that. I suspect that the worm in the box acts like an Archimedes screw, winding the grease up the column on the one lock but doesn't drag it back on the other. Result: the grease fills the column and is forced out at the top.