Crank case drain plug seal

[EddieDay]

While changing the oil in my 1958 M18S, when I removed the crank case drain plug I found it was sealed with a fibre washer and a steel washer. That looked wrong to me as it seems that the steel washer would allow leakage if it was on the Crank case side of the joint or the plug side of the joint. The fibre washer alone is not thick ènough to allow for the unthreaded part of the plug so I fitted a second fibre washer. I am sure one of you experienced guys knows what the correct arrangement is.

[MikeM.]

Both the singles and twins drain plugs were originally fitted with steel washers

[Duncan]

My preference is to fit copper washers on the drain plug, the ones I have seen are usually undercut between the hex and the thread so the thickness of the washer is not an issue. I was interested to read in the parts book that 022538 is called "Filter, Magnetic" !

[EddieDay]

Thanks Mike and Duncan. I'll probably put the steel washer back in.