Morris Minor Owners Club

Hi all, very quick question, what size socket to undo the gearbox oil nut please?

Thanks

Matt

i think the filler is 11/16 or 17 or 18 mm i cant remember off hand i just find a socket to fit , and i use a imperial / metric adjustiable spanner to do the gearbox sump plug . both are on a taper so dont go mad doing them back up sorry i cant be more help , hope you liked the little joke .

3/8 whitworth according to the chart at the head of the mechanical forum.

did not know there was a chart on here

Chart, list whatever you want to call it is at the top of the mechanical forum headed spanner sizes Very useful it is too.

It's the starting handle size (ie same as the wheel nuts) - and it's a bolt, not a nut if you are thinking of the filler.

ah, same as the wheel nuts, good to know, thanks bmc, and everyone else too.

Any thanks for the 'bolt' 'nut' clarification too, good to know.

Matt

PS: Rear axle oil.....same as engine/gearbox (20w50)?
(I know steering rack is different)

No, rear axle should be hypoid gear oil - EP 90. Do not use engine oil.....

Rear axle and rack are EP90/80. NOT engine oil ! Ideally the gearbox is SAE 30 - the '20' in the 20/50 is a bit low, and it doesn't get hot enough to reach the '50' grade which would be too high anyway.

Matt,

All the threads on a Minor (apart from the MM) were originally 'Imperial' - generally UNF/UNC for mechanical parts, and BSF/BSW for body fittings. It you are going to do anything remotely 'serious', you do need to get a set of both spanner series, plus sockets too!

Just a note about BSF/BSW spanner sizes. Originally a BSW nut and bolt had a hexagon head 'one size bigger' than BSF, and also used a spanner size 'one size bigger' than BSF. It can be a bit confusing to understand the actual nut/bolt thread diameter, for example the wing fixing bolts use a 1/4" BSW / 5/16" BSF spanner, but are a 5/16" diameter thread (BSF). On a Minor I would always think in BSF sizes, as that will give the correct nut/bolt thread diameter as well.

The gearbox filler plug is a lovely combination - the plug head size is 3/8" BSW / 7/16" BSF and the thread itself is 1/2" BSPT!

BSPT (British Standard Pipe Taper).

I note that some of the BSP taps I have are marked up BSPF (British Standard Pipe Fitting) which was the original calling.

Great, thanks for you help everyone.

Matt