Bishop Steering Box Oil Chage

[SpqrEddie]

Hello!
no drain plug on the bishop steering biox, right? it has to be taken apart to drain it, correct?
Anybody would know how much oil (or "Kamoil" lubricant as reccomended by the manual), to use?
Thanks!
Eddie

[nicksonsticks]

Hi Eddie, you might be able to empty out most of the old oil by using a syringe and some screen washer tube via the filler plug, or if you have access to a vacuum pump even better. Also slackening the brass stator tube nut might allow some of the oil to drain out. You might have to warm the oil up a bit to make it easier to extract.  I don't know exact quantity but I'm guessing it would be to the bottom of the filler hole, other members might have more info on this.
I've used a steering box lubricant on previous projects with steering boxes which is like a blend of oil and grease and seems less prone to leaking around the oil seal, I'll post some info which may be of help.
Kind regards Nick

[nicksonsticks]

https://www.ahspares.co.uk/austin-healey/big-healey/oils-lubricants/steering-box-lube.aspx

[SpqrEddie]

Thank you Nick for sharing your experience.
The instruction manual is confusing, in the text they suggest special steering box lubricant, in the summary lubricaiton table 90W oil is indicated.
But i would think the special lubricant is better.
I belive, the Austin Healey had similar steering box as i have seen some Austin Healey sockists carry some spares for it.
Best,
Edmondo

[SpqrEddie]

Hello,
in addition to the Penrite, that seems more a grease then oil, i see that Millers produce a specific worm steering box oil.

https://www.millersoils.co.uk/wp-content/uploads/2019/11/Vintage-Worm-Steering-Box-Oil.pdf

I will go for this one i think.

Eddie

[Michael Trotter]

Good evening Eddie

I see no reason to change the lubricant in the steering box. Nor, apparently, did Bishop or they would have provided a drain plug. The steering box lubricant is not subject to contamination as is the engine oil. Nor is it subject to high temperatures as are the gearbox and rear axle oils.  AC specified Kamoil which is trade name which seems to have vanished. When I Googled it I got into stuff about coconut oil which didn't seem relevant. I think the Penrite and Miller stuff is probably what in the old days we called semi-liquid grease. We used to put it in the rear axle of a Model T Ford because oil walked past the felt seals and soaked the brake linings. 

I think either semi-liquid grease or a heavy oil, say 90 or 140, would be fine but I would avoid mixing them. Not clear to me whether the level is low because of leakage or whether you simply want to change it. Level should be up to the base of the filler plug. If you have significant leakage you will need to replace the oil seal on the rocker shaft but you can come back to that later. Can you dip a slim screwdriver into what is in the box and identify it as semi-liquid grease or oil?  If you can my advice is to top up with what's already in there and keep an eye on level/leakage.

On another subject elsewhere you queried tyre pressures. AC's recommendation for standard Michelin X on 16" wheels was F22/R24.These are fine for normal road use. Bear in mind that that the Aceca weighs well under a ton and the tyre sections are quite high for this weight. Tyre pressures are a 'trade off' - if you are a 'boy racer' you will increase ultimate cornering power with higher pressures but at the expense of ride comfort. We have got used to our modern cars which run on 32/35 but they weigh over a ton and a half. Look at Longstone Tyres who quote something like 30/32. When I queried this they said they regarded that as maximum pressures and customers could reduce them for more ride comfort. My advice is to settle for 22/24 and increase only if you are prepared to sacrifice ride comfort.

Michael

[SpqrEddie]

Thank you Michael,
I belive Kamoil was a very thick oil, as in the Instruction book they says 90 EP can be used.
I think Penrite is semi liqid-grease, but i belive the Miller is thick oil. As i wanted to stick to factory reccomandation i have ordered the Miller in the end. As soon as here i will be able to report on it.
I want to change it as i am changing all the fluids and greasing and oiling all the car.
I agree with you that the steering box lubricant is not something that has to be changed regularly, but even if what is in the car looks fine and clean is probably in the car since 60 years!
i could top it up, but i dont know what is in there, this is why i was planning on changing it all.
I dont want to mess with the steering box either, so my plan was to siringe out what is in there from the filler hole, and replace with what i think is the most similar to this phantomatic Kamoil!
The steering box is not leaking, but is exuding a bit. It is mid way if i gauge it. Probably not bad for a 60 years old box and seals!
i belive what is currently inside is the Kamoil, it is very thick and smell like transmission oil (see photos).

Thank you for the advice on the tyre pressure!

[SpqrEddie]

Hello,
i did replaced the steering box oil with the Miller Vintage Worm Steering Box Oil.
https://www.millersoils.co.uk/wp-content/uploads/2019/11/Vintage-Worm-Steering-Box-Oil.pdf
It is a very very thick oil. that seemed thicker than the oil that was in the box. May be still the original Kamoil? who knows...
I have siringed out all the oil that i could (the box was half filled, so it has leaked some through the years, and filled the box to the filling hole with the Millers.
The box took approximately 150cc. Not sure how much of the old oil was still in, but i belive very little.
Best,
Eddie