Gearbox oil

[benwall101]

Hello

I recently purchaced my moggy and relised she was leaking gear oil a bit.
I just changed my gearbox oil as i knew it was leaking small drops in the garage. i measured the amount that came out of the gear box and it was just under 500ml, but it the manual it says the gearbox should have 1.3l of gearbox oil in it. So i have toped up my gearbox oil to 1.3l and can no see it through the bit were you top it up.
Have i done the right thing?

Also noticed that the gearbox drain bolt that is were it leaks and a good amount of the threads are still not in the gear box they are exposed (found it like this so refited it like this)

Thanks Ben

[chickenjohn]

Hello Ben,
No the drain plug doesn't have to do all the way up to the threads, just hand tight with a spanner or ratchet, be careful not to cross thread, so put the plug in by hand at first.

The gearbox is filled from the hole in the left hand side of the transmission tunnel, after lifting the carpet and removing the bung. I presume this is where you are referring to.

20W50 engine oil must be used in the Minor gearbox (assuming your car is an "A" series engined Minor and not a very early side valve series MM) and you pour in 20W50 to the bottom of the threads in the hole then screw the filler plug back on.

I use an old EP90 bottle (emptied of EP90, with 20W50 written on the side) to add the 20W50 to the gearbox.

Congrats on the purchase of your new Moggie!

[mogbob]

Ben
Just keep an eye on the " Leak " as you have only recently acquired your Moggie.If it still persists, you may have to drain the gearbox to remedy the situation.When replacing the drain plug wrap some PTFE/ plumbers tape around the thread and refit.As chickenjohn suggests don't employ gorilla tactics to tighten it up, otherwise you will have a permanent leak with stripped threads.Refill and away you go.

If you have a willing assistant / mate available you could be a " little Dutch boy / finger in the dyke variety " and seal the hole
with your finger, whilst your mate wraps the drain plug with PTFE tape for you to replace.This would save draining the gearbox oil.

If you are jacking up the car, the usual safety precautions apply, use decent jack and axle stands and chock the rear wheels.Plenty of newspaper under the area and have rags/ paper towels to hand to mop up.
You've done the right thing so far.Keep the questions coming to the Forum if you are not sure of anything.

Safe motoring.
Bob

[benwall101]

Thanks guys for the help its realy helpful!

So to check the level just see if its visable through the top up hole?

[mogbob]

Ben
You've got it...I fill until it "just " dribbles over the edgeof the hole on the side of the gearbox, as chickenjohn expalined.if you can visibly see it, that's near enough.
Bob

[bmcecosse]

The Manual instructs to use SAE 30 engine oil..............

[JOWETTJAVELIN]

The Manual instructs to use SAE 30 engine oil..............

But that was 50 years ago when straight grades were all the rage and multigrades not yet invented.

[bmcecosse]

Ahhh - but some are only too keen to quote the Manual to me in other matters.........

[chickenjohn]

Ahhh - but some are only too keen to quote the Manual to me in other matters.........

Yes, where there is a big difference is materials and where materials have moved on with development over time. I suppose BMC would advocate filling the gearbox with grease....

EP90 oil in the rear axle and steering rack, ben and Grease in the suspennsion, propshaft and handbrake cable nipples.

[bmcecosse]

Ahh - but the 'understanding' moves on as well as the materials....... hence the universal move to putting grease in steering racks - rather than runny oil that hides in the boots.........

[autolycus]

I'm concerned at the change in formulation of engine oils over the last 50 years. Back then, didn't they use sensible quantities of ZDDP and other additives for protection under boundary lubrication conditions? The need to protect these wretched cats they now fit means that ZDDP levels are now much reduced in most oils. That's why I use oils sold for diesel engines in classic petrol engines, and gear oil, which these days has far less aggressive EP additives than of yore, in gearboxes. I do realise that synchromesh needs friction, but Real Men don't need synchro, do they?

Kevin

[les]

The reason the drain and filler plugs have some threads exposed Ben, is because they have tapered threads, the further they are screwed in the tighter they get. There comes a point where the last part of the plug is of too large a diameter to screw in any more, hence the exposed threads.

[bmcecosse]

And if overtightened can crack the casing.........

[chickenjohn]

Ahh - but the 'understanding' moves on as well as the materials....... hence the universal move to putting grease in steering racks - rather than runny oil that hides in the boots.........

Universal to who?? EP90 for the rack and it doesn't run out if the gaiters/ cable ties are in good condition.

[chickenjohn]

I'm concerned at the change in formulation of engine oils over the last 50 years. Back then, didn't they use sensible quantities of ZDDP and other additives for protection under boundary lubrication conditions? The need to protect these wretched cats they now fit means that ZDDP levels are now much reduced in most oils. That's why I use oils sold for diesel engines in classic petrol engines, and gear oil, which these days has far less aggressive EP additives than of yore, in gearboxes. I do realise that synchromesh needs friction, but Real Men don't need synchro, do they?

Kevin

Good point! old style SAE30 could actually be better for our engines due to the ZDDP additives.

[bmcecosse]

I don't suggest it runs OUT of the boots - it runs and hides IN the boots.. Later racks of similar design are all greased.

[chickenjohn]

Good! the boots keep the oil there and as the steering rack is turned the rack receives splash lubrication!

[JOWETTJAVELIN]

The answer to the ZDDP and modern oil worries is to buy an oil specially blended for classics, such as Morris Lubricants or Halford's greenbase classic oil (which I use and find it to be a real quality oil).

BUT I've argued this point before and it seems some people are content to run on supermarket filth.

[liammonty]

Hi JOWETT,

Not wanting to sound mean, but you have managed to kill 2 (admittedly weak) engines in a short space of time, even using super-duper high quality oil!! Imagine how quickly they would have blown if you hadn't used that premium quality stuff! ;) The Halfords Classic oil is basically overpriced Comma oil in a tin can. Like you, I try to use something half-way decent, but to be honest, if you change it frequently, pretty much any rubbish you can buy is ging to be superior to what was available in the 40's, 50's and 60's.

[JOWETTJAVELIN]

That's fair enough but I only 'killed' 1 engine.... the other was faulty before I put it in (unseen ebay buy). What do you expect when the bearings are made from white metal?

The bores and rings were in top condition for a unit nearing 90k... just a shame the crank was already 060 thou under. It ran on Duckhams all its life and (probably as a result of this) will only need a bottom end overhaul.

Anyone can use whatever oil they like - it's a personal choice. But I suppose those who buy cheap oil also fill up with supermarket petrol, because "all the tankers come out of the same refinery" and Shell V-Power is no different...

The cheapest is the dearest in the long run.